On entry: values to be used to control step size choice during integration. If any
CONi=0.0 on entry, it is replaced by its default value described below. In most cases this is the recommended setting.
CON1,
CON2, and
CON3 are factors used to bound step size changes. If the current step size
h fails, then the modulus of the next step size is bounded by
CON1×h. The default value of
CON1 is
2.0. Note that the new step size may be used with a method of different order to the failed step. If the initial step size is
h, then the modulus of the step size on the second step is bounded by
CON3×h. At any other stage in the integration, if the current step size is
h, then the modulus of the next step size is bounded by
CON2×h. The default values are
10.0 for
CON2 and
1000.0 for
CON3.
CON4,
CON5 and
CON6 are ‘tuning’ constants used in determining the next order and step size. They are used to scale the error estimates used in determining whether to keep the same order of the BLEND method, decrease the order or increase the order respectively. The larger the value of
CONi, for
i=4,5,6, the less likely the choice of the corresponding order. The default values are:
CON4=1.2,
CON5=1.3,
CON6=1.4.
Constraints:
These constraints must be satisfied after any zero values have been replaced by their default values.
- 0.0<CON1<CON2<CON3;
- CONi>1.0, for i=2,3,…,6.