NAG Fortran Library for Win32 Applications, Mark 22

FLDLL224ML - License Managed

Windows XP/Vista/7 DLL, Intel Visual Fortran

Users' Note



Contents


1. Introduction

This document is essential reading for every user of the NAG Fortran Library implementation specified in the title. It provides implementation-specific detail that augments the information provided in the NAG Mark 22 Library Manual (which we will refer to as the Library Manual). Wherever that manual refers to the "Users' Note for your implementation", you should consult this note.

In addition, NAG recommends that before calling any Library routine you should read the following reference material (see Section 6):

(a) Essential Introduction
(b) Chapter Introduction
(c) Routine Document

The libraries supplied with this implementation have been compiled in a manner that facilitates the use of multiple threads.

2. Post Release Information

Please check the following URL:

http://www.nag.co.uk/doc/inun/fl22/dll4ml/postrelease.html

for details of any new information related to the applicability or usage of this implementation.

3. Restrictions

As with the Mark 20 and Mark 21 NAG Fortran Library DLLs, the Compaq Visual Fortran calling convention is used (ifort /iface:cvf). In essence this means that parameters are accessed by reference. Character strings are passed as address/length pairs (i.e. /iface:mixed_str_len_arg, which is automatically turned on if /iface:cvf is specified).

Fortran 90/95/2003 users are advised that the compiled *.mod files (the interface blocks) have been compiled with the Intel Fortran Compiler 10.1 and are intended for use with that compiler. Users may have to compile the interface blocks themselves if they wish to use them with a different compiler.

When the DLLs are used with a non-Intel compiler, please note that two input/output systems are in use: those of Intel for library routines and of course the compiler's own input/output routines for the calling program. This means that programs like the E04UDF example program cannot read the data from just one file. This is because the program reads some of the data using its input/output system. When the option setting routine tries to read the data file, the Intel input/output routines are used. The two input/output systems are completely disjoint and so in particular Intel has no knowledge of the position in the data file that the program input/output system has reached. The problem is circumvented by having two separate data files. Routines affected by this are mainly the option setting routines in chapters H02 and E04. This implementation contains modified example programs for the affected routines, to circumvent the problem.

4. General Information

For best performance, we recommend that you should use the variant of the NAG Fortran Library which is based on the supplied Math Kernel Library (MKL) i.e. FLDLL224M_mkl.lib/FLDLL224M_mkl.dll. However if you use a version of the MKL different from the version used in creating this implementation and you have problems when calling a NAG routine, we suggest that you use the above library with the supplied MKL, or the self-contained library FLDLL224M_nag.lib/FLDLL224M_nag.dll.

4.1. Accessing the Library

In this section we assume that the Library has been installed in the default folder:

  c:\Program Files\NAG\FL22\fldll224ml
If this folder does not exist, please consult the system manager (or the person who did the installation). In some of the following subsections, this folder is referred to as install dir.

We also assume that the default shortcut for the Library command prompt is placed in the Start Menu under:

  Start|All Programs|NAG|FL22|

If this shortcut does not exist, please consult the system manager (or the person who did the installation). (Other shortcuts created as part of the Library installation procedure are also assumed to be in this location.)

To ensure that the NAG DLLs are accessible at runtime, the install dir\bin folder must be on the path. If the MKL-based version of the Library is to be used, the install dir\MKL_ia32_10.1\bin folder must also be on the path, but should appear later in the path than the install dir\bin folder, since the NAG versions of a few Basic Linear Algebra Subprograms (BLAS) / linear algebra routines (LAPACK) are included in FLDLL224M_mkl.dll to avoid problems with the vendor versions. (See Section 5 for details.)

To check the accessibility of the NAG DLLs, run the program NAG_Fortran_DLL_info.exe which is available from the Start Menu shortcut

  Start|All Programs|NAG|FL22|NAG Fortran Library for Win32
      Applications (FLDLL224ML)|Check NAG DLL Accessibility (FLDLL224ML)
See Section 4.2.3 of the Installer's Note for details of this utility.

See Section 4.1.1.1 below for information on setting environment variables from a command prompt. The PATH, LIB and INCLUDE environment variables may already have been set globally as part of the installation or this may be done via the Control Panel. (On Windows XP, from Control Panel select System | Advanced | Environment Variables; on Vista or Windows 7 from the Control Panel home select System and Maintenance (on Vista) / System and Security (on Windows 7), then System | Advanced System Settings | Environment Variables... .) Either the user variables or the system variables may be edited, although Administrator privileges will be required to edit the system ones. Edit the PATH environment variable to include

  c:\Program Files\NAG\FL22\fldll224ml\batch;
  c:\Program Files\NAG\FL22\fldll224ml\bin;
  c:\Program Files\NAG\FL22\fldll224ml\MKL_ia32_10.1\bin;
  existing path
add or edit the LIB environment variable to include
  c:\Program Files\NAG\FL22\fldll224ml\lib;
  c:\Program Files\NAG\FL22\fldll224ml\MKL_ia32_10.1\lib;
  any existing library path
add or edit the INCLUDE environment variable to include
  c:\Program Files\NAG\FL22\fldll224ml\nag_interface_blocks;
  any existing include path
substituting the correct folder where the NAG Fortran DLLs are installed if necessary.

In this DLL implementation, for convenience, the MKL symbols are exported directly from the NAG import library FLDLL224M_mkl.lib, so it is not necessary to specify the MKL interface libraries libguide40.lib, mkl_intel_s_dll.lib, mkl_intel_thread_dll.lib and mkl_core_dll.lib as well. However, if the MKL interface libraries are specified, it is important that the NAG import library precedes them, i.e. the order should be

  FLDLL224M_mkl.lib libguide40.lib mkl_intel_s_dll.lib
      mkl_intel_thread_dll.lib mkl_core_dll.lib
because certain parts of the MKL should not be used (see Section 5).

Information on calling the NAG Fortran DLLs from various different environments is given below. More information on calling NAG Fortran or C DLLs is available on the NAG web site at

  http://www.nag.co.uk/numeric/Num_DLLhelp.asp
More information specific to this product may be available from the Post Release Information page:

http://www.nag.co.uk/doc/inun/fl22/dll4ml/postrelease.html

4.1.1. Calling the DLLs from Intel Fortran

The NAG Fortran DLLs have been built using Intel Fortran 10.1. To call the DLLs from a program compiled with Intel Fortran 11 or later, you may need to move or rename the files libifcoremd.dll and libmmd.dll in the install dir\bin folder, so that the correct Intel Fortran runtime DLL is picked up. To facilitate this, the batch file hide_ifort_rtls.bat has been provided in the install dir\bin folder. This file will rename the Intel Fortran 10.1 run-time libraries libifcoremd.dll and libmmd.dll in that folder. The file expose_ifort_rtls.bat, also in that folder, is provided to convert the names back again. (Note that appropriate access permissions may need to be in place for these batch files to work.)

4.1.1.1. From a command window

To access this implementation from a command window some environment variables need to be set (if this has not been done globally - see above).

The shortcut:

  Start|All Programs|NAG|FL22|NAG Fortran Library for Win32
      Applications (FLDLL224ML)|FLDLL224ML Command Prompt

may be used to start a command prompt window with the correct settings for the INCLUDE, LIB and PATH environment variables for the Library and the supplied MKL.

If the shortcut is not used, you can set the environment variables by running the batch file envvars.bat for this implementation. The default location of this file is:

  c:\Program Files\NAG\FL22\fldll224ml\batch\envvars.bat
If the file is not in the default location, you can locate it by searching for the file envvars.bat containing fldll224ml.

You may then compile and link to the NAG Fortran Library on the command line using one of the following commands:

  ifort /iface:cvf /MD driver.f FLDLL224M_mkl.lib
  ifort /iface:cvf /MD driver.f FLDLL224M_nag.lib
where driver.f is your application program.

The first command will use the DLL without the NAG version of the BLAS/LAPACK procedures (FLDLL224M_mkl.lib) and with the MKL DLLs. The second command will use the DLL with the NAG version of the BLAS/LAPACK procedures (FLDLL224M_nag.lib). The option /MD should be used to ensure linking with the correct run-time libraries.

Note that /MD is equivalent to specifying /libs:dll /threads.

If your program uses multiple threads, you should also compile with the /automatic option, e.g.:

  ifort /iface:cvf /MD /automatic driver.f FLDLL224M_mkl.lib

Please note that the Intel Visual Fortran compiler environment variables must be set in the command window. For more details refer to the User's Guide for the compiler.

4.1.1.2. From MS Visual Studio

The instructions given here are for Visual Studio .NET 2003/2005/2008 with Intel Fortran Compiler 10.1. Other versions may vary.

To ensure that the NAG DLLs are accessible at runtime, the PATH environment variable must be set such that the location of the NAG Fortran DLLs, specifically the folder install dir\bin, is on the path. If the MKL version of the DLL is required, the location of the MKL DLLs, install dir\MKL_ia32_10.1\bin must also be on the path, but should appear after the install dir\bin folder. Once Visual Studio has been opened, it is possible to set up the directories for use with Intel Fortran in this and all subsequent projects which use this compiler. One way to do so is:

  1. Select the Tools pull down menu, and click on Options.
  2. In the Options window, click on Intel(R) Fortran (or Intel(R) Visual Fortran) and then choose Compilers in the left window pane. (In some versions of Visual Studio you may need to click on Show all settings to see the Intel compiler options.)
  3. In the right window pane, click on the '...' to the right of the Libraries panel.
  4. Add the path to the NAG DLL import library to the Set Directory List window. The default location is:
    "c:\Program Files\NAG\FL22\fldll224ml\lib"
  5. In this implementation, there is no need to add the path to the MKL interface libraries, since the BLAS and LAPACK symbols are exported from both NAG import libraries (FLDLL224M_nag.lib and FLDLL224M_mkl.lib). (Note that this behaviour is different from some other NAG library implementations.) However, any MKL library folders in the Libraries path must come after the path to the NAG Library, as it is important that these are not picked up before the NAG Library, as explained in Section 4.1.
  6. Click on the OK button in the Set Directory List window.
  7. In the right window pane, click on the '...' to the right of the Includes panel.
  8. Add the path to the NAG interface blocks to the Set Directory List window. The default location is:
    "c:\Program Files\NAG\FL22\fldll224ml\nag_interface_blocks"
  9. Click on the OK button in the Set Directory List window.
  10. Click on the OK button in the Options window.
Having done this, if an Intel Fortran project requires a library or NAG interface block during the compilation and linking process then the full path to the library and interface block do not need to be specified.

The interface block is simply accessed by inserting a USE statement as described in greater detail in Section 4.3.

Whilst the above changes will apply to every Intel Fortran project, the following tasks need to be performed for each individual Intel Fortran project.

The library is intended to be run in fully optimised mode, so to avoid any warning messages, you might decide to set the active configuration to Release. You can do this from the Toolbar or alternatively via the Build|Configuration Manager menus. Note that if you work in Debug mode, you may receive a warning message about conflicting C run-time libraries.

There are a number of ways to add the NAG Library to the project. We describe just two; choose the one that most suits you.

If the Solution Explorer window is open then make sure that the group project (the first line) is NOT selected. From the Project menu, choose the project Properties item. (Alternatively right-click on a specific single project in the Solution Explorer and choose Properties.)

From the form, click/expand Linker in the leftmost panel and then choose Input. The right hand panel will now have an Additional Dependencies entry, and you need to type FLDLL224M_mkl.lib in this location to use the FLDLL224M_mkl.lib library and MKL. Press the OK button. If you wish to use the self-contained NAG Library FLDLL224M_nag.lib then you need to add FLDLL224M_nag.lib instead.

You will also need to set the calling convention to "CVF". From the Properties form, click/expand Fortran and then choose External Procedures. Click on the Calling Convention entry in the right hand panel and select CVF from the drop-down list. Selecting this option will automatically change the entry for String Length Argument Passing to After Individual String Argument when you click on Apply or OK; this is the convention required by this implementation of the NAG Library.

We also recommend that you use the multithreaded DLL version of the runtime library. From the Properties form, click/expand Fortran in the leftmost panel and then choose Libraries. Click on the Runtime Library entry in the right hand panel and select Multithread DLL from the drop-down list.

For a multithreaded application, as well as selecting a multithreaded run-time library, you should set the /automatic (or /Qauto) compiler flag, to ensure that all local variables are allocated on the stack. To set this option, from the Properties form click/expand Fortran and then choose Data. Click on the Local Variable Storage entry in the right hand panel and select Local Variables AUTOMATIC from the drop-down list. Press the OK button to accept the changes and close the form.

The Properties information may also be accessed via the Toolbar. With the project selected in Solution Explorer, choose the Properties Window button on the Toolbar. In the ensuing window choose then the rightmost Property Pages icon. Select the appropriate settings as detailed in the paragraphs above.

The project should now compile and link using the appropriate choice from the Build menu.

To run a program that does not require input or output redirected from standard input or standard output, from within the Microsoft Development Environment, the program may be executed via the Debug menu (by selecting Start Without Debugging, for example).

If a data file needs to be attached to the standard input or the output of a program needs to be redirected to the standard output, we recommend that you run the executable from a command prompt window to avoid the limitations of Visual Studio.

4.1.2. Calling the DLLs from Compaq Visual Fortran

Assuming that the folder containing the libraries has been added to the LIB environment variable, you may compile and link to the NAG Fortran Library on the command line in the following manner:

  f90 driver.f FLDLL224M_mkl.lib
or
  f90 driver.f FLDLL224M_nag.lib
where driver.f is your application program.

4.1.3. Calling the DLLs from the NAG Fortran Compiler (NAGWare f95)

Commands such as the following may be used to call the NAG DLLs from the NAG Fortran Compiler (NAGWare f95):
  f95 -f77 -w=obs -o driver.exe driver.f "install dir\lib\FLDLL224M_mkl.lib"
or
  f95 -f77 -w=obs -o driver.exe driver.f "install dir\lib\FLDLL224M_nag.lib"
where driver.f is your application program and driver.exe is the executable produced.

The full pathname of the FLDLL224M_mkl.lib or FLDLL224M_nag.lib file must be specified and must be enclosed within quotes if it contains spaces.

4.1.4. Calling the DLLs from Absoft Pro Fortran

Modified versions of the example programs d01ajfe.f and f07cefe.f are provided to illustrate the use of the NAG DLLs with Absoft F95 Version 10.2. These files can be found in the folder
  install dir\samples\absoft_fortran_examples

There are four issues to consider when using this NAG Library with Absoft Pro Fortran:

  1. All real arguments and functions are DOUBLE PRECISION.
  2. All library and call back procedures must be declared STDCALL (see lines marked "CHANGE1" in d01ajfe.f and f07cefe.f).
  3. CHARACTER arguments to the NAG library procedures must be passed using the CVF protocol. This protocol passes the length of the CHARACTER argument as an integer value immediately after the CHARACTER argument itself. The Absoft Pro Fortran compilers pass CHARACTER arguments as integer values after the formal argument list.

    To force the protocol, use the sequence VAL(LOC(...)). The LOC(...) function takes the address of its argument. The VAL(...) function passes its argument by value. Then use VAL(...) immediately after this sequence to pass the length of the argument.

    In the accompanying code the formal argument TRANS (actual argument 'No transpose') in the call to the routine DGTTRS in the example program f07cefe.f is replaced by two arguments:
    VAL(LOC(TRANS)), VAL(12)
    (see lines marked "CHANGE2"), where TRANS is declared and assigned the value 'No transpose' in the lines marked "NEW". Similar changes have been made for the arguments MATRIX, DIAG and TITLE in the call to the routine X04CAF.
  4. Subroutine arguments to a routine need to be specified in the same file as the calling routine. (This is true of all non-stdcall compilers.)

Assuming that the folder containing the libraries has been added to the LIB environment variable, you may compile and link to the NAG Fortran Library on the command line using one of the following commands:

  f95 driver.f FLDLL224M_mkl.lib
  f95 driver.f FLDLL224M_nag.lib
where driver.f is your application program.

Routines which use auxiliary routines passed as arguments will not link correctly with Version 10.2 of the Absoft compiler because the symbols exported from the NAG library are not compatible with the symbols expected by the Absoft linker. It is hoped that future releases of the compiler will be able to link to the NAG libraries. Even with this restriction, the majority of NAG routines will compile and link with the Absoft 10.2 compiler.

Note that, because of the different calling conventions used, when calling the NAG Fortran Library from the Absoft Compiler, it may be easier to use the DLLs included with the product FLW3222DCL. See the Post Release Notes for that product for details: http://www.nag.co.uk/doc/inun/fl22/w32dcl/postrelease.html

4.1.5. Calling the DLLs from Silverfrost (Salford) FTN95

You will need SLINK version 1.26 or higher and FTN95 version 1.23 or higher.

No source file changes are necessary to call the DLLs from FTN95. However, since FTN95 uses a variant of the cdecl calling convention, the compiler has to be told that the routines in the DLLs are to be called using the CVF calling convention. This can be accomplished using the /IMPORT_LIB command line switch as follows:

  ftn95 driver.f /import_lib "install dir\bin\FLDLL224M_mkl.dll" /link
or
  ftn95 driver.f /import_lib "install dir\bin\FLDLL224M_nag.dll" /link
The full pathname of install dir should be specified to the DLLs and should be enclosed within quotes if it contains spaces. The effect of this is to assume that all exported names in the DLL are CVF STDCALL and that any use of them should use the CVF STDCALL calling convention. External names passed via the argument list to a routine in a NAG DLL are automatically adjusted for whether or not they occur in the same source.

It is also possible to compile and link using commands such as

  ftn95 /f_stdcall driver.f
  slink driver.obj "install dir\bin\FLDLL224M_mkl.dll"
As with compilation, the full path to the DLLs should be specified here, within quotes if the pathname contains spaces. It is worth emphasising that the linker should link directly against the DLLs, not the *.lib files.

Plato3 is the Integrated Development Environment (IDE) that is provided with the more recent versions of FTN95. To use Plato3 for a project involving a NAG routine:

  1. From the File menu choose 'New Project'.
  2. Select 'Fortran Application' and set a name for the project and location.
  3. In the Project Explorer window, right-click on the source files and enter the files comprising the project. For example you might choose the NAG example program C05NBFE.F.
  4. Right-click on the 'References' in the Project Explorer window and enter the name of the NAG DLL you wish to use e.g. FLDLL224M_mkl.dll.
  5. If your compiler is older than version 5.2 then make sure that the project does NOT use the 'Checkmate' option; prior to version 5.2 FTN95 did not work correctly with the 'Checkmate' option and the NAG STDCALL DLL. Choose for example 'Release Win32' from the drop down menu on the toolbar.
  6. Ensure that the STDCALL option is used. To specify the /F_STDCALL option go to Project | Properties | Compiler Options | Miscellaneous. There is an "Extra compiler options" property that you can set to "/F_STDCALL". Alternatively you may right-click on the NAG DLL in the Project Explorer pane, under 'References', and then under 'Properties' set the checkbox to indicate STDCALL.
  7. Unfortunately Plato3 doesn't currently support redirection of standard input/output. You can avoid this by explicitly opening the files within the main program. For example to send the results to a file c:\test.res insert the statement
            open(6,file='c:\test.res') 
    
    in the main program before any write statements to channel 6.

4.1.6. Calling the DLLs from PGI Fortran

Assuming that the LIB and PATH environment variables have been set up appropriately for your installation of the NAG Library, the command for linking to the Mark 22 DLLs using pgf90 is:

  pgf90 driver.f FLDLL224M_mkl.lib -o driver.exe
(for the MKL-based variant of the Library), or
  pgf90 driver.f FLDLL224M_nag.lib -o driver.exe
(for the self-contained variant of the Library).

This has been tested using version 8.0-6 of the PGI pgf90 compiler.

4.1.7. Calling the DLLs from Lahey/Fujitsu Fortran

A modified version of the example program D02CJFE.F is provided to illustrate the use of the NAG DLLs with Lahey/Fujitsu Fortran. This file (lahey.f) can be found in the folder
  install dir\samples\lahey_fortran_example
The advice given here has been tested using Lahey Fortran versions 7.1 and 7.2.
  1. Code changes

    There are a few simple changes that must be made to a standard Fortran program to allow the NAG DLLs to be used by Lahey Fortran:

    1. For each NAG routine called directly insert a DLL_IMPORT statement in the calling program or subprogram e.g.
            DLL_IMPORT D02CJF
      
    2. For each NAG routine passed as an argument to a routine in the DLL insert a DLL_IMPORT statement in the calling program or subprogram e.g.
            DLL_IMPORT D02CJW
      
    3. For each user-supplied subroutine or function used as an argument to a routine in the DLL insert a DLL_IMPORT statement in the calling program or subprogram e.g.
            DLL_IMPORT OUT
      
      and in the user-supplied subroutine or function insert a DLL_EXPORT statement i.e.
            DLL_EXPORT OUT
      
      should be inserted in subroutine OUT.

      Remember to declare all these subroutines and functions as EXTERNAL and also to declare the type of any functions used. The names of imported functions are case sensitive; this means that NAG names must be in upper case.

      The second family of changes concern the treatment of character arguments which must be adjusted to suit the convention used by the NAG DLLs. Character arguments must be stripped of the hidden length argument that Lahey places at the end of all the arguments; this is accomplished by passing the value of the address of the argument as follows: VAL(POINTER(char_arg)). Then, to conform to the NAG DLL standard, the length argument needs to be added immediately following the character argument. Both arguments are passed by value. Here is an example:

            CALL D02CJF (X, XEND2, N, Y, FCN, TOL, VAL(POINTER('Default')),
           + VAL(LEN('Default')), OUT, G, W, IFAIL)
      
  2. Compilation and Linking

    Use the compiler switch "-ml bc" to compile all routines in the program. The Lahey compiler uses this switch to specify that the stdcall calling convention be used. The import library file for the DLL should be in a location specified in the LIB environment variable. Alternatively, the programmer can specify the location using the -LIBPATH linker option. Specifying the location of the library on the compiler line is a third possibility i.e.

          lf95 d02cjfe.f "install dir\lib\FLDLL224M_mkl.lib" -ml bc
    
    or
          lf95 d02cjfe.f "install dir\lib\FLDLL224M_nag.lib" -ml bc
    
  3. Execution

    As ever, make sure that the DLLs are on the PATH.

Note that, because of the different calling conventions used, when calling the NAG Fortran Library from the Lahey Compiler, it may be easier to use the DLLs included with the product FLW3222DCL. See the Post Release Notes for that product for details: http://www.nag.co.uk/doc/inun/fl22/w32dcl/postrelease.html

4.1.8. Calling the DLLs from GNU gfortran

Commands such as the following may be used for calling the NAG Fortran Library Mark 22 DLLs from gfortran, where driver.f is your application program and driver.exe is the executable produced.

Using gfortran from a Windows Command Prompt:

  gfortran -mrtd driver.f "install dir\lib\FLDLL224M_mkl.lib" -o driver.exe
or
  gfortran -mrtd driver.f "install dir\lib\FLDLL224M_nag.lib" -o driver.exe
Using gfortran from a Cygwin xterm:
  gfortran -mrtd driver.f "install dir/lib/FLDLL224M_mkl.lib" -o driver.exe
or
  gfortran -mrtd driver.f "install dir/lib/FLDLL224M_nag.lib" -o driver.exe

Character strings arguments demand special attention. Immediately after the character string argument, pass by value the length of the string. For example:

         DEV = G01FAF(TAIL,%VAL(1),P,IFAIL)

In the example program D02CJFE.F, you need to replace the formal argument RELABS (actual argument 'Default') in all the calls to the routine D02CJF by:

         'Default',%VAL(7)

If the argument is a character array, pass the length of each array element.

This information has been tested with GNU Fortran 4.4.0.

Modified versions of the example programs D02CJFE.F and G01FAFE.F are provided to illustrate the use of the NAG DLLs with gfortran. These files can be found in the folder

  install dir\samples\gfortran_examples

4.1.9. Calling the DLLs from Microsoft Visual C++ / Visual Studio

If you have Microsoft Visual Studio .NET 2003 or above then, with care, the NAG Fortran DLLs may be used from within a C or C++ environment. To assist the user make the mapping between Fortran and C types, a C/C++ header file is provided. It is recommended that users wishing to use a Fortran DLL routine either copy and paste the relevant section of the appropriate file into their C or C++ applications (making sure that the relevant #defines etc. are also copied from the top of the file) or simply include the header file with their application.

Examples of the use of the DLLs from C and C++ are given in the install dir\samples\c_examples and install dir\samples\cpp_examples folders. (Note that if the e04cbfcppclass.sln file is loaded into Visual Studio 2005 or later, the Conversion Wizard will update the files in the project/solution as necessary.)

A document, techdoc.html, giving more detailed advice on calling the DLLs from C and C++ is available in install dir\c_headers. There is also a shortcut to this document on the Start Menu under

  Start|All Programs|NAG|FL22|NAG Fortran Library for Win32
      Applications (FLDLL224ML)|C & C++ Header File Information
by default. Note that some changes will be needed if you paste code from one of the C examples given there into a C++ file since, if __cplusplus is defined, the header file provided uses C++ reference arguments for scalars, and therefore the "address of" operator should not be used. See Section 3 of the techdoc.html document for more details.

Key information:

Assuming that the folder containing the libraries has been added to the LIB environment variable, you may compile and link your C application program to the NAG Fortran Library on the command line in the following manner:
  cl driver.c /DUSE_STDCALL FLDLL224M_mkl.lib
or
  cl driver.c /DUSE_STDCALL FLDLL224M_nag.lib
where driver.c is your application program. This assumes that the folder containing the header files has been added to the INCLUDE environment variable. If not, you could use:
  cl driver.c /DUSE_STDCALL FLDLL224M_mkl.lib /I"install dir\c_headers"
or
  cl driver.c /DUSE_STDCALL FLDLL224M_nag.lib /I"install dir\c_headers"

The following instuctions apply to Visual Studio .NET 2003, Visual Studio 2005 and Visual Studio 2008. Later versions may vary.

If you are working under the Visual Studio IDE, set the following values to enable linking to work. Under the project's Properties, select Configuration Properties | Linker | Input and add FLDLL224M_mkl.lib or FLDLL224M_nag.lib to the Additional Dependencies field. If the LIB environment variable has not been set elsewhere, select Configuration Properties | Linker | General and add install dir\lib to the Additional Library Directories field.

Note that, with Microsoft C++, you may need to use the /EHsc compiler switch with the command line C++ examples.

4.1.10. Calling the DLLs from Intel C/C++

The header files and discussion in Calling the DLLs from Microsoft Visual C++ apply equally to Intel C.

Assuming that the folder containing the libraries has been added to the LIB environment variable, you may compile and link your C application program to the NAG Fortran Library on the command line in the following manner:

  icl driver.c /DUSE_STDCALL FLDLL224M_mkl.lib /I"install dir\c_headers"
or
  icl driver.c /DUSE_STDCALL FLDLL224M_nag.lib /I"install dir\c_headers"
where driver.c is your application program.

4.1.11. Calling the DLLs from Borland C/C++

The discussion in Calling the DLLs from Microsoft Visual C++ applies equally to Borland. Borland import libraries are not supplied but may easily be constructed from the DLLs as follows:
  impdef name.def "install dir\bin\name.dll"
  implib name.lib name.def
where name denotes the name of the NAG DLL i.e. FLDLL224M_mkl or FLDLL224M_nag. The first statement constructs a module definition file, name.def, and the second takes this module definition file and constructs an import library, name.lib. Do not be alarmed by warning messages from IMPLIB. These arise from the number of alternative symbols exported from the DLL in order to provide convenient alternatives for different users.

Assuming that the folder containing the import libraries has been added to the LIB environment variable, you may compile and link your C application program to the NAG Fortran Library on the command line in the following manner:

  bcc32 -DUSE_STDCALL -I"install dir\c_headers" driver.c name.lib
where driver.c is your application program.

Alternatively you may add the location of the NAG header files to the configuration file bcc32.cfg. For more details please see the compiler documentation. If you have amended the configuration file then you may simply type:

  bcc32 -DUSE_STDCALL driver.c name.lib

4.1.12. Calling the DLLs from GNU gcc / g++

The header files and discussion in Calling the DLLs from Microsoft Visual C++ apply equally to gcc / g++.

Commands such as the following may be used to call the NAG Fortran Library for Win32 Applications from gcc or g++, where driver.c or driver.cpp is your application program and driver.exe is the executable produced.

Note that each command should be issued on a single line; the commands are shown split over two lines here to avoid truncation if this note is printed.

Using gcc to compile a C program from a Windows Command Prompt:

  gcc -D USE_STDCALL -D _WIN32 -I "install dir\c_headers" driver.c 
      "install dir\lib\FLDLL224M_mkl.lib" -o driver.exe
or
  gcc -D USE_STDCALL -D _WIN32 -I "install dir\c_headers" driver.c
      "install dir\lib\FLDLL224M_nag.lib" -o driver.exe

Using gcc to compile a C program from a Cygwin xterm:

  gcc -D USE_STDCALL -D _WIN32 -I "install dir/c_headers" driver.c
      "install dir/lib/FLDLL224M_mkl.lib" -o driver.exe
or
  gcc -D USE_STDCALL -D _WIN32 -I "install dir/c_headers" driver.c
      "install dir/lib/FLDLL224M_nag.lib" -o driver.exe

Using g++ to compile a C++ program from a Windows Command Prompt:

  g++ -D USE_STDCALL -D _WIN32 -I "install dir\c_headers" driver.cpp
      "install dir\lib\FLDLL224M_mkl.lib" -o driver.exe
or
  g++ -D USE_STDCALL -D _WIN32 -I "install dir\c_headers" driver.cpp
      "install dir\lib\FLDLL224M_nag.lib" -o driver.exe

Using g++ to compile a C++ program from a Cygwin xterm:

  g++ -D USE_STDCALL -D _WIN32 -I "install dir/c_headers" driver.cpp
      "install dir/lib/FLDLL224M_mkl.lib" -o driver.exe
or
  g++ -D USE_STDCALL -D _WIN32 -I "install dir/c_headers" driver.cpp
      "install dir/lib/FLDLL224M_nag.lib" -o driver.exe

This information has been tested with the versions of gcc/g++ that report "gcc version 3.4.5 (mingw special)" and "gcc (GCC) 3.3.3 (cygwin special)".

4.1.13. Calling the DLLs from Microsoft Visual Basic for Applications / Excel

The Fortran DLLs provided in this implementation are ideally suited for use within an Excel spreadsheet. The routines may be called from Visual Basic for Applications (VBA) code. (Note that VBA and Visual Basic 6 (VB 6) have many similarities, and the same NAG Declare statements are used for both.)

Examples of use of the DLLs from within Excel are given in the install dir\samples\excel_examples folder. The folder install dir\samples\excel_examples\linear_algebra contains the file xls_demo.txt. This file gives some hints about using NAG DLLs from within Excel spreadsheets. See also the VB 6 examples for further illustrations of calling the NAG DLLs from VB 6 / VBA.

Key information:

4.1.14. Calling the DLLs from Microsoft Visual Basic 6

Visual Basic 6 (VB 6) and Visual Basic for Applications (VBA) have many similarities, so much of the VBA specific information above applies directly to VB 6. Note especially the remarks about array conventions and string handling.

Examples of use of the DLLs from Visual Basic 6 are given in the install dir\samples\vb6_examples folder. See also the VBA code within the Excel examples for further illustrations of calling the NAG DLLs from VB 6 / VBA.

Key information:

4.1.15. Calling the DLLs from Microsoft Visual Basic .NET

Many of the library routines are callable from Visual Basic .NET (VB.NET). Examples of use of the DLLs from VB.NET are given in the install dir\samples\vb.net_examples folder. (These examples were created using Visual Studio .NET 2003; if loaded into Visual Studio 2005 or later, the solution and project files will be converted by the Visual Studio Conversion Wizard.)

Key information:

4.1.16. Calling the DLLs from C#

For information on calling the NAG Fortran Library DLLs from C# see http://www.nag.co.uk/numeric/csharpinfo.asp. The method illustrated there is applicable to the DLLs in this implementation.

You may also be interested in the NAG Library for .NET – see http://www.nag.co.uk/microsoft_dotnet.asp for details.

4.1.17. Calling the DLLs from Java

For information on calling the NAG C Library and Fortran Library DLLs from Java see http://www.nag.co.uk/doc/TechRep/html/Tr2_09/Tr2_09.asp. The method illustrated there is applicable to the DLLs in this implementation.

4.1.18. Calling the DLLs from Python

For information on calling the NAG Fortran Library DLLs from Python using F2PY see the PDF file http://www.nag.co.uk/doc/TechRep/pdf/TR1_08.pdf. The method illustrated there is applicable to the DLLs in this implementation.

4.1.19. Calling the DLLs from R

For information on calling the NAG Fortran Library DLLs from R see http://www.nag.co.uk/numeric/RunderWindows.asp. The method illustrated there is applicable to the DLLs in this implementation.

4.1.20. The NAG Library edition of Simfit

The NAG Library edition of Simfit uses the DLL implementation of the NAG Fortran Library as its source of algorithms. For more information about the NAG Library edition of Simfit see http://www.nag.co.uk/educationuk/simfit.asp.

4.1.21. Calling the DLLs from Other Environments

For information on calling the NAG Fortran Library for Win32 Applications from environments not mentioned above, please see the Post Release Information page:

http://www.nag.co.uk/doc/inun/fl22/dll4ml/postrelease.html

or contact us via one of the addresses listed in the Appendix.

4.2. Accessibility Check

To check whether the DLLs included in this library implementation are accessible from the current environment, run the program NAG_Fortran_DLL_info.exe which is available from the Start Menu shortcut
  Start|All Programs|NAG|FL22|NAG Fortran Library for Win32
      Applications (FLDLL224ML)|Check NAG DLL Accessibility (FLDLL224ML)
See Section 4.2.3 of the Installer's Note for details of this utility.

Note that this program should be closed after use (by pressing a key to dismiss the window), otherwise performance may be impared.

4.3. Interface Blocks

The NAG Fortran Library interface blocks define the type and arguments of each user callable NAG Fortran Library routine. These are not essential to calling the NAG Fortran Library from Fortran programs. Their purpose is to allow the Fortran compiler to check that NAG Fortran Library routines are called correctly. The interface blocks enable the compiler to check that:

(a) subroutines are called as such;
(b) functions are declared with the right type;
(c) the correct number of arguments are passed; and
(d) all arguments match in type and structure.

These interface blocks have been generated automatically by analysing the source code for the NAG Fortran Library. As a consequence, and because these files have been thoroughly tested, their use is recommended in preference to writing your own declarations.

The NAG Fortran Library interface block files are organised by Library chapter. The module names are:

  nag_f77_a_chapter
  nag_f77_c_chapter
  nag_f77_d_chapter
  nag_f77_e_chapter
  nag_f77_f_chapter
  nag_f77_g_chapter
  nag_f77_h_chapter
  nag_f77_m_chapter
  nag_f77_p_chapter
  nag_f77_s_chapter
  nag_f77_x_chapter
These are supplied in pre-compiled form (.mod files).

If you use the Library command prompt shortcut or set the environment variables by running the batch file envvars.bat for this implementation (see Section 4.1.1.1), you can use any of the commands described in Section 4.1.1.1 to access these modules since the environment variable INCLUDE will be set.

In order to make use of these modules from existing Fortran 77 code, the following changes need to be made:

The above steps need to be done for each unit (main program, function or subroutine) in your code.

These changes are illustrated by showing the conversion of the Fortran 77 version of the example program for NAG Fortran Library routine D01DAF. Please note that this is not exactly the same as the example program that is distributed with this implementation. Each change is surrounded by comments boxed with asterisks.

*     D01DAF Example Program Text
*     Mark 14 Revised. NAG Copyright 1989.
*****************************************************
* Add USE statements for relevant chapters          *
      USE NAG_F77_D_CHAPTER, ONLY: D01DAF
*                                                   *
*****************************************************
*     .. Parameters ..
      INTEGER          NOUT
      PARAMETER        (NOUT=6)
*     .. Local Scalars ..
      DOUBLE PRECISION ABSACC, ANS, YA, YB
      INTEGER          IFAIL, NPTS
*     .. External Functions ..
      DOUBLE PRECISION FA, FB, PHI1, PHI2A, PHI2B
      EXTERNAL         FA, FB, PHI1, PHI2A, PHI2B
*     .. External Subroutines ..
******************************************************
* EXTERNAL declarations need to be removed.          *
*     EXTERNAL         D01DAF
*                                                    *
******************************************************
*     .. Executable Statements ..
      WRITE (NOUT,*) 'D01DAF Example Program Results'
      YA = 0.0D0
      YB = 1.0D0
      ABSACC = 1.0D-6
      WRITE (NOUT,*)
      IFAIL = 1
*
      CALL D01DAF(YA,YB,PHI1,PHI2A,FA,ABSACC,ANS,NPTS,IFAIL)
*
      IF (IFAIL.LT.0) THEN
         WRITE (NOUT,99998) ' ** D01DAF returned with IFAIL = ', IFAIL
      ELSE
*
         WRITE (NOUT,*) 'First formulation'
         WRITE (NOUT,99999) 'Integral =', ANS
         WRITE (NOUT,99998) 'Number of function evaluations =', NPTS
         IF (IFAIL.GT.0) WRITE (NOUT,99998) 'IFAIL = ', IFAIL
         WRITE (NOUT,*)
         WRITE (NOUT,*) 'Second formulation'
         IFAIL = 1
*
         CALL D01DAF(YA,YB,PHI1,PHI2B,FB,ABSACC,ANS,NPTS,IFAIL)
*
         WRITE (NOUT,99999) 'Integral =', ANS
         WRITE (NOUT,99998) 'Number of function evaluations =', NPTS
         IF (IFAIL.GT.0) WRITE (NOUT,99998) 'IFAIL = ', IFAIL
      END IF
*
99999 FORMAT (1X,A,F9.4)
99998 FORMAT (1X,A,I5)
      END
*
      DOUBLE PRECISION FUNCTION PHI1(Y)
*     .. Scalar Arguments ..
      DOUBLE PRECISION Y
*     .. Executable Statements ..
      PHI1 = 0.0D0
      RETURN
      END
*
      DOUBLE PRECISION FUNCTION PHI2A(Y)
*     .. Scalar Arguments ..
      DOUBLE PRECISION Y
*     .. Intrinsic Functions ..
      INTRINSIC        SQRT
*     .. Executable Statements ..
      PHI2A = SQRT(1.0D0-Y*Y)
      RETURN
      END
*
      DOUBLE PRECISION FUNCTION FA(X,Y)
*     .. Scalar Arguments ..
      DOUBLE PRECISION X, Y
*     .. Executable Statements ..
      FA = X + Y
      RETURN
      END
*
      DOUBLE PRECISION FUNCTION PHI2B(Y)
*****************************************************
* Add USE statements for relevant chapters          *
      USE NAG_F77_X_CHAPTER, ONLY: X01AAF
*                                                   *
*****************************************************
*     .. Scalar Arguments ..
      DOUBLE PRECISION Y
*     .. External Functions ..
******************************************************
* Function Type declarations need to be removed.     *
*     DOUBLE PRECISION X01AAF
*                                                    *
******************************************************
******************************************************
* EXTERNAL declarations need to be removed.          *
*     EXTERNAL         X01AAF
*                                                    *
******************************************************
*     .. Executable Statements ..
      PHI2B = 0.5D0*X01AAF(0.0D0)
      RETURN
      END
*
      DOUBLE PRECISION FUNCTION FB(X,Y)
*     .. Scalar Arguments ..
      DOUBLE PRECISION X, Y
*     .. Intrinsic Functions ..
      INTRINSIC        COS, SIN
*     .. Executable Statements ..
      FB = Y*Y*(COS(X)+SIN(X))
      RETURN
      END

Modified versions of all the example program source files, which use the modules, are available in the zip file source_interface_blocks.zip. This can be found in the folder install dir\examples.

4.4. Example Programs

The example results distributed were generated at Mark 22, using the software described in Section 2.2 of the Installer's Note. These example results may not be exactly reproducible if the example programs are run in a slightly different environment (for example, a different Fortran compiler, a different compiler library, or a different set of BLAS or LAPACK routines). The results which are most sensitive to such differences are: eigenvectors (which may differ by a scalar multiple, often -1, but sometimes complex); numbers of iterations and function evaluations; and residuals and other "small" quantities of the same order as the machine precision.

Note that the example material has been adapted, if necessary, from that published in the Library Manual, so that programs are suitable for execution with this implementation with no further changes. The distributed example programs should be used in preference to the versions in the Library Manual wherever possible.

The example programs are most easily accessed by one of the following batch files:

The batch files need the environment variable NAG_FLDLL224ML.

As mentioned in Section 4.1.1.1, the installation procedure provides a shortcut which starts a Command Prompt with local environment variables. The environment variables include NAG_FLDLL224ML. This shortcut is, by default, placed in the Start Menu under

  Start|All Programs|NAG|FL22|NAG Fortran Library for Win32
      Applications (FLDLL224ML)|FLDLL224ML Command Prompt
If the shortcut is not used, you need to set this environment variable. It can be set by running the batch file envvars.bat for this implementation. The default location of this file is:
  c:\Program Files\NAG\FL22\fldll224ml\batch\envvars.bat
If the file is not in the default location, you can locate it by searching for the file envvars.bat containing fldll224ml.

Each of the nag_example* batch files mentioned above will provide you with a copy of an example program (and its data, if any), compile the program and link it with the appropriate libraries (showing you the compile command so that you can recompile your own version of the program). Finally, the executable program will be run, writing its output to a file.

The example program concerned is specified by the argument to the command, e.g.

  nag_example_mkl e04ucf
will copy the example program and its data into the files e04ucfe.f and e04ucfe.d in the current folder and process them to produce the example program results in the file e04ucfe.r.

The distributed example results are those obtained with the library FLDLL224M_mkl.dll, (using the MKL BLAS and LAPACK routines). Running the examples with the self-contained library (using the NAG BLAS and LAPACK routines) may give slightly different results.

4.5. Interpretation of Bold Italicised Terms

In order to support all implementations of the Library, the Manual has adopted a convention of using bold italics to distinguish terms which have different interpretations in different implementations.

For this double precision implementation, the bold italicised terms used in the Library Manual should be interpreted as follows:

real                  means REAL
double precision      means DOUBLE PRECISION
complex               means COMPLEX
complex*16            means COMPLEX*16 (or equivalent)
basic precision       means DOUBLE PRECISION
additional precision  means quadruple precision
reduced precision     means REAL

Another important bold italicised term is machine precision, which denotes the relative precision to which double precision floating-point numbers are stored in the computer, e.g. in an implementation with approximately 16 decimal digits of precision, machine precision has a value of approximately 1.0D-16.

The precise value of machine precision is given by the routine X02AJF. Other routines in Chapter X02 return the values of other implementation-dependent constants, such as the overflow threshold, or the largest representable integer. Refer to the X02 Chapter Introduction for more details.

The bold italicised term block size is used only in Chapters F07 and F08. It denotes the block size used by block algorithms in these chapters. You only need to be aware of its value when it affects the amount of workspace to be supplied – see the parameters WORK and LWORK of the relevant routine documents and the Chapter Introduction.

4.6. Explicit Output from NAG Routines

Certain routines produce explicit error messages and advisory messages via output units which have default values that can be reset by using X04AAF for error messages and X04ABF for advisory messages. (The default values are given in Section 5.) The maximum record lengths of error messages and advisory messages (including carriage control characters) are 80 characters, except where otherwise specified.

5. Routine-specific Information

Any further information which applies to one or more routines in this implementation is listed below, chapter by chapter.

  1. D06

    When running some routines in this chapter you may need to increase the stack size to avoid a stack overflow exception. One way of doing this is to use a command such as
      ifort /iface:cvf /MD driver.f FLDLL224M_mkl.lib /link /stack:128000000
    
    which will pass the specified stack size to the linker.

  2. F06, F07 and F08

    In Chapters F06, F07 and F08, alternate routine names are available for BLAS and LAPACK derived routines. For details of the alternate routine names please refer to the relevant Chapter Introduction. Note that applications should reference routines by their BLAS/LAPACK names, rather than their NAG-style names, for optimum performance.

    Many LAPACK routines have a "workspace query" mechanism which allows a caller to interrogate the routine to determine how much workspace to supply. Note that LAPACK routines from the MKL may require a different amount of workspace from the equivalent NAG versions of these routines. Care should be taken when using the workspace query mechanism.

    In this implementation calls to the NAG version of the following Basic Linear Algebra Subprograms (BLAS) and linear algebra routines (LAPACK) are included in the library FLDLL224M_mkl.dll to avoid problems with the vendor version:

      DGGGLM     DGGLSE     ZGELS      ZGGGLM     ZGGLSE
    

  3. G02

    The value of ACC, the machine-dependent constant mentioned in several documents in the chapter, is 1.0D-13.

  4. P01

    On hard failure, P01ABF writes the error message to the error message unit specified by X04AAF and then stops.

  5. S07 - S21

    Functions in these chapters will give error messages if called with illegal or unsafe arguments. The constants referred to in the Library Manual have the following values in this implementation:
    S07AAF  F_1   = 1.0E+13
            F_2   = 1.0E-14
    
    S10AAF  E_1   = 1.8715E+1
    S10ABF  E_1   = 7.080E+2
    S10ACF  E_1   = 7.080E+2
    
    S13AAF  X_hi  = 7.083E+2
    S13ACF  X_hi  = 1.0E+16
    S13ADF  X_hi  = 1.0E+17
    
    S14AAF  IFAIL  = 1 if X > 1.70E+2
            IFAIL  = 2 if X < -1.70E+2
            IFAIL  = 3 if abs(X) < 2.23E-308
    S14ABF  IFAIL  = 2 if X > X_big = 2.55E+305
    
    S15ADF  X_hi  = 2.65E+1
    S15AEF  X_hi  = 2.65E+1
    S15AFF  underflow trap was necessary
    S15AGF  IFAIL  = 1 if X >= 2.53E+307
            IFAIL  = 2 if 4.74E+7 <= X < 2.53E+307
            IFAIL  = 3 if X < -2.66E+1
    
    S17ACF  IFAIL  = 1 if X > 1.0E+16
    S17ADF  IFAIL  = 1 if X > 1.0E+16
            IFAIL  = 3 if 0.0E0 < X <= 2.23E-308
    S17AEF  IFAIL  = 1 if abs(X) > 1.0E+16
    S17AFF  IFAIL  = 1 if abs(X) > 1.0E+16
    S17AGF  IFAIL  = 1 if X > 1.038E+2
            IFAIL  = 2 if X < -5.7E+10
    S17AHF  IFAIL  = 1 if X > 1.041E+2
            IFAIL  = 2 if X < -5.7E+10
    S17AJF  IFAIL  = 1 if X > 1.041E+2
            IFAIL  = 2 if X < -1.9E+9
    S17AKF  IFAIL  = 1 if X > 1.041E+2
            IFAIL  = 2 if X < -1.9E+9
    S17DCF  IFAIL  = 2 if abs(Z) < 3.92223E-305
            IFAIL  = 4 if abs(Z) or FNU+N-1 > 3.27679E+4
            IFAIL  = 5 if abs(Z) or FNU+N-1 > 1.07374E+9
    S17DEF  IFAIL  = 2 if imag(Z) > 7.00921E+2
            IFAIL  = 3 if abs(Z) or FNU+N-1 > 3.27679E+4
            IFAIL  = 4 if abs(Z) or FNU+N-1 > 1.07374E+9
    S17DGF  IFAIL  = 3 if abs(Z) > 1.02399E+3
            IFAIL  = 4 if abs(Z) > 1.04857E+6
    S17DHF  IFAIL  = 3 if abs(Z) > 1.02399E+3
            IFAIL  = 4 if abs(Z) > 1.04857E+6
    S17DLF  IFAIL  = 2 if abs(Z) < 3.92223E-305
            IFAIL  = 4 if abs(Z) or FNU+N-1 > 3.27679E+4
            IFAIL  = 5 if abs(Z) or FNU+N-1 > 1.07374E+9
    
    S18ADF  IFAIL  = 2 if 0.0E0 < X <= 2.23E-308
    S18AEF  IFAIL  = 1 if abs(X) > 7.116E+2
    S18AFF  IFAIL  = 1 if abs(X) > 7.116E+2
    S18DCF  IFAIL  = 2 if abs(Z) < 3.92223E-305
            IFAIL  = 4 if abs(Z) or FNU+N-1 > 3.27679E+4
            IFAIL  = 5 if abs(Z) or FNU+N-1 > 1.07374E+9
    S18DEF  IFAIL  = 2 if real(Z) > 7.00921E+2
            IFAIL  = 3 if abs(Z) or FNU+N-1 > 3.27679E+4
            IFAIL  = 4 if abs(Z) or FNU+N-1 > 1.07374E+9
    
    S19AAF  IFAIL  = 1 if abs(X) >= 5.04818E+1
    S19ABF  IFAIL  = 1 if abs(X) >= 5.04818E+1
    S19ACF  IFAIL  = 1 if X > 9.9726E+2
    S19ADF  IFAIL  = 1 if X > 9.9726E+2
    
    S21BCF  IFAIL  = 3 if an argument < 1.583E-205
            IFAIL  = 4 if an argument >= 3.765E+202
    S21BDF  IFAIL  = 3 if an argument < 2.813E-103
            IFAIL  = 4 if an argument >= 1.407E+102
    

  6. X01

    The values of the mathematical constants are:
    X01AAF (pi)    = 3.1415926535897932
    X01ABF (gamma) = 0.5772156649015328
    

  7. X02

    The values of the machine constants are:

    The basic parameters of the model

    X02BHF = 2
    X02BJF = 53
    X02BKF = -1021
    X02BLF = 1024
    X02DJF = .TRUE.
    

    Derived parameters of the floating-point arithmetic

    X02AJF = 1.11022302462516E-16
    X02AKF = 2.22507385850721E-308
    X02ALF = 1.79769313486231E+308
    X02AMF = 2.22507385850721E-308
    X02ANF = 2.22507385850721E-308
    

    Parameters of other aspects of the computing environment

    X02AHF = 1.42724769270596E+45
    X02BBF = 2147483647
    X02BEF = 15
    X02DAF = .TRUE.
    

  8. X03

    X03AAW and X03AAX are internal routines which are exported from this NAG Fortran Library implementation as they may be useful when calling the DLLs from environments such as Excel (as explained below).

    The routine X03AAW changes the floating-point control word such that it sets the working precision to double precision (53-bit mantissa) and sets the rounding mode to nearest. X03AAW takes a single INTEGER argument, which is used to store the floating-point control word value on input and return it to the calling program, so this routine is also used to retrieve the original (i.e. on entry) value of the control word.

    The routine X03AAX sets the floating-point control word to the value specified in its single INTEGER argument. It is typically used to restore the floating-point control word to its original value after a call to X03AAW, but may, of course, be used to set a different value.

    The Library is designed to operate in double precision (53-bit) mode, not the extended precision mode also possible on the chip. A normal Intel Fortran program will operate, by default, in this mode, but other environments may re-set the floating-point control word so that the chip operates in extended precision mode. Excel is one such environment. To obtain consistent behaviour the user may wish to use X03AAW directly before entering any other Library routine in order to restore the mode of operation to double precision.

    A corollary of the behaviour of these two routines is that they may also be used as a "get and set" pair, with X03AAW used to get the value of the floating-point control word on entry, and X03AAX used to set a new value (or restore the original value), but note the "side-effect" of calling X03AAW, namely that this will set the control word as described above.

  9. X04

    The default output units for error and advisory messages for those routines which can produce explicit output are both Fortran Unit 6.

6. Documentation

The Library Manual is available as a separate installation, via download from the NAG website, or from the distribution CD if you have one. It is also available directly on the CD. The most up-to-date version of the documentation is accessible via the NAG website at http://www.nag.co.uk/numeric/FL/FLdocumentation.asp.

The Library Manual is supplied in the following formats:

The following main index files have been provided for these formats:

	nagdoc_fl22\xhtml\FRONTMATTER\manconts.xml
	nagdoc_fl22\pdf\FRONTMATTER\manconts.pdf
	nagdoc_fl22\html\FRONTMATTER\manconts.html
If the Library Manual has been installed locally, these index files are available from the Start Menu under
  Start|All Programs|NAG|FL22|NAG Fortran Library Manual (XHTML + MathML)
  Start|All Programs|NAG|FL22|NAG Fortran Library Manual (PDF)
  Start|All Programs|NAG|FL22|NAG Fortran Library Manual (PDF + HTML Index)
respectively, by default. Use your web browser to navigate from here.

Advice on viewing and navigating the formats available can be found in the Online Documentation document.

Note that if you are using Internet Explorer, all links within the XHTML/MathML version to example source, data and results files and PDF files will be diverted from the local file system to the NAG website to avoid security restrictions which prevent the display of these pages. If you are using any other browser then local links to examples and PDF files are retained.

In addition the following are provided:

The latter is available from the Start Menu under
  Start|All Programs|NAG|FL22|NAG Fortran Library for Win32
      Applications (FLDLL224ML)|Users' Note
by default.

7. Support from NAG

(a) Contact with NAG

Queries concerning this document or the implementation generally should be directed to NAG at one of the addresses given in the Appendix. Users subscribing to the support service are encouraged to contact one of the NAG Response Centres (see below).

(b) NAG Response Centres

The NAG Response Centres are available for general enquiries from all users and also for technical queries from sites with an annually licensed product or support service.

The Response Centres are open during office hours, but contact is possible by fax, email and phone (answering machine) at all times.

When contacting a Response Centre, it helps us deal with your enquiry quickly if you can quote your NAG site reference and NAG product code (in this case FLDLL224ML).

(c) NAG Websites

The NAG websites provide information about implementation availability, descriptions of products, downloadable software, product documentation and technical reports. The NAG websites can be accessed at the following URLs:

http://www.nag.co.uk/, http://www.nag.com/ or http://www.nag-j.co.jp/

(d) NAG Electronic Newsletter

If you would like to be kept up to date with news from NAG then please register to receive our free electronic newsletter, which will alert you to announcements about new products or product/service enhancements, technical tips, customer stories and NAG's event diary. You can register via one of our websites, or by contacting us at nagnews@nag.co.uk.

(e) Product Registration

To ensure that you receive information on updates and other relevant announcements, please register this product with us. For NAG Library products this may be accomplished by filling in the online registration form at http://www.nag.co.uk/numeric/Library_Registration.asp.

8. User Feedback

Many factors influence the way that NAG's products and services evolve, and your ideas are invaluable in helping us to ensure that we meet your needs. If you would like to contribute to this process, we would be delighted to receive your comments. Please contact any of the NAG Response Centres (shown below).

Appendix - Contact Addresses

NAG Ltd
Wilkinson House
Jordan Hill Road
OXFORD  OX2 8DR                         NAG Ltd Response Centre
United Kingdom                          email: support@nag.co.uk

Tel: +44 (0)1865 511245                 Tel: +44 (0)1865 311744
Fax: +44 (0)1865 310139                 Fax: +44 (0)1865 310139

NAG Inc
801 Warrenville Road
Suite 185
Lisle, IL  60532-4332                   NAG Inc Response Center
USA                                     email: support@nag.com

Tel: +1 630 971 2337                    Tel: +1 630 971 2337
Fax: +1 630 971 2706                    Fax: +1 630 971 2706

Nihon NAG KK
Hatchobori Frontier Building 2F
4-9-9
Hatchobori
Chuo-ku
Tokyo
104-0032
Japan
email: help@nag-j.co.jp

Tel: +81 (0)3 5542 6311
Fax: +81 (0)3 5542 6312