# MatMFFDCheckPositivity

Checks that all entries in U + h*a are positive or zero, decreases h until this is satisfied.

### Synopsis

    #include "petscmat.h"
    PetscErrorCode PETSCMAT_DLLEXPORT MatMFFDCheckPositivity(void* dummy,Vec U,Vec a,PetscScalar *h)

Collective on Vec

### Input Parameters

| U | - base vector that is added to
| a | - vector that is added
| h | - scaling factor on a
| dummy | - context variable (unused)

### Options Database Keys

-mat_mffd_check_positivity -

Notes: This is rarely used directly, rather it is passed as an argument to MatMFFDSetCheckh()

### See Also

MatMFFDSetCheckh()

Level:advanced
Location:src/mat/impls/mffd/mffd.c
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