petsc-3.10.5 2019-03-28

PetscOptionsScalar

Gets the scalar value for a particular option in the database.

Synopsis

#include "petscsys.h"   
PetscErrorCode  PetscOptionsScalar_Private(PetscOptionItems *PetscOptionsObject,const char opt[],const char text[],const char man[],PetscScalar currentvalue,PetscScalar *value,PetscBool  *set)

Logically Collective on the communicator passed in PetscOptionsBegin()

Input Parameters

	opt	- option name
	text	- short string that describes the option
	man	- manual page with additional information on option
	currentvalue	- the current value; caller is responsible for setting this value correctly. Normally this is done with either

                PetscOptionsScalar(..., obj->value,&object->value,...) or

                value = defaultvalue

                PetscOptionsScalar(..., value,&value,&flg);

                if (flg) {

Output Parameter

	value	- the value to return
	flg	- PETSC_TRUE if found, else PETSC_FALSE

Notes

If the user does not supply the option at all value is NOT changed. Thus you should ALWAYS initialize value if you access it without first checking if the set flag is true.

The default/currentvalue passed into this routine does not get transferred to the output value variable automatically.