PetscIntMultTruncate#

Computes the product of two positive PetscInt and truncates the value to slightly less than the maximal possible value

Synopsis#

Not Collective; No Fortran Support

Input Parameters#

  • a - the PetscInt value

  • b - the second value

Returns#

the result as a PetscInt value

Notes#

Use PetscInt64Mult() to compute the product of two PetscInt as a PetscInt64

Use PetscRealIntMultTruncate() to compute the product of a PetscReal and a PetscInt and truncate to fit a PetscInt

Use PetscIntMultError() to compute the product of two PetscInt if you wish to generate an error if the result will not fit in a PetscInt

Developers Notes#

We currently assume that PetscInt addition can never overflow, this is obviously wrong but requires many more checks.

This is used where we compute approximate sizes for workspace and need to insure the workspace is index-able.

See Also#

PetscBLASInt, PetscMPIInt, PetscInt, PetscBLASIntCast(), PetscInt64Mult(), PetscIntMultError(), PetscIntSumError(), PetscIntSumTruncate()

Level#

advanced

Location#

include/petscsys.h


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