PetscOptionsScalar#

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

Synopsis#

#include "petscsys.h"
PetscErrorCode PetscOptionsScalar(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,&obj->value,...) or
                 value = defaultvalue
                 PetscOptionsScalar(..., value,&value,&flg);
                 if (flg) {

Output Parameters#

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 flg is PETSC_TRUE.

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

Must be between a PetscOptionsBegin() and a PetscOptionsEnd()