﻿ g05sm Method
g05sm generates a vector of pseudorandom numbers from a log-normal distribution with parameters $\mu$ and ${\sigma }^{2}$.

# Syntax

C#
```public static void g05sm(
int n,
double xmu,
double var,
G05..::..G05State g05state,
double[] x,
out int ifail
)```
Visual Basic
```Public Shared Sub g05sm ( _
n As Integer, _
xmu As Double, _
var As Double, _
g05state As G05..::..G05State, _
x As Double(), _
<OutAttribute> ByRef ifail As Integer _
)```
Visual C++
```public:
static void g05sm(
int n,
double xmu,
double var,
G05..::..G05State^ g05state,
array<double>^ x,
[OutAttribute] int% ifail
)```
F#
```static member g05sm :
n : int *
xmu : float *
var : float *
g05state : G05..::..G05State *
x : float[] *
ifail : int byref -> unit
```

#### Parameters

n
Type: System..::..Int32
On entry: $n$, the number of pseudorandom numbers to be generated.
Constraint: ${\mathbf{n}}\ge 0$.
xmu
Type: System..::..Double
On entry: $\mu$, the mean of the distribution of $\mathrm{ln} x$.
var
Type: System..::..Double
On entry: ${\sigma }^{2}$, the variance of the distribution of $\mathrm{ln} x$.
Constraint: ${\mathbf{var}}\ge 0.0$.
g05state
Type: NagLibrary..::..G05..::..G05State
An Object of type G05.G05State.
x
Type: array<System..::..Double>[]()[][]
An array of size [n]
On exit: the $n$ pseudorandom numbers from the specified log-normal distribution.
ifail
Type: System..::..Int32%
On exit: ${\mathbf{ifail}}={0}$ unless the method detects an error or a warning has been flagged (see [Error Indicators and Warnings]).

# Description

The distribution has PDF (probability density function)
 $fx=1xσ⁢2πexp-ln x-μ22σ2if ​x>0,fx=0otherwise,$
i.e., $\mathrm{ln} x$ is normally distributed with mean $\mu$ and variance ${\sigma }^{2}$. g05sm evaluates $\mathrm{exp} {y}_{i}$, where the ${y}_{i}$ are generated by g05sk from a Normal distribution with mean $\mu$ and variance ${\sigma }^{2}$, for $\mathit{i}=1,2,\dots ,n$.
One of the initialization methods (G05KFF not in this release) (for a repeatable sequence if computed sequentially) or (G05KGF not in this release) (for a non-repeatable sequence) must be called prior to the first call to g05sm.

# References

Kendall M G and Stuart A (1969) The Advanced Theory of Statistics (Volume 1) (3rd Edition) Griffin
Knuth D E (1981) The Art of Computer Programming (Volume 2) (2nd Edition) Addison–Wesley

# Error Indicators and Warnings

Errors or warnings detected by the method:
${\mathbf{ifail}}=1$
On entry, ${\mathbf{n}}<0$.
${\mathbf{ifail}}=2$
On entry, unable to calculate $\mathrm{exp}\left({\mathbf{xmu}}\right)$ as xmu is too large.
${\mathbf{ifail}}=3$
On entry, ${\mathbf{var}}<0.0$.
${\mathbf{ifail}}=4$
 On entry, state vector was not initialized or has been corrupted.
${\mathbf{ifail}}=-9000$
An error occured, see message report.
${\mathbf{ifail}}=-8000$
Negative dimension for array $〈\mathit{\text{value}}〉$
${\mathbf{ifail}}=-6000$
Invalid Parameters $〈\mathit{\text{value}}〉$

Not applicable.

None.