# MatAssemblyBegin

Begins assembling the matrix. This routine should be called after completing all calls to MatSetValues().

### Synopsis

    #include "petscmat.h"
    PetscErrorCode PETSCMAT_DLLEXPORT MatAssemblyBegin(Mat mat,MatAssemblyType type)

Collective on Mat

### Input Parameters

| mat | - the matrix
| type | - type of assembly, either MAT_FLUSH_ASSEMBLY or MAT_FINAL_ASSEMBLY

### Notes

MatSetValues() generally caches the values. The matrix is ready to use only after MatAssemblyBegin() and MatAssemblyEnd() have been called. Use MAT_FLUSH_ASSEMBLY when switching between ADD_VALUES and INSERT_VALUES in MatSetValues(); use MAT_FINAL_ASSEMBLY for the final assembly before using the matrix.

### See Also

MatAssemblyEnd(), MatSetValues(), MatAssembled()

Level:beginner
Location:src/mat/interface/matrix.c
Index of all Mat routines
Table of Contents for all manual pages
Index of all manual pages

### Examples

src/mat/examples/tutorials/ex2.c.html
src/mat/examples/tutorials/ex5.c.html
src/ksp/pc/examples/tutorials/ex1.c.html
src/ksp/pc/examples/tutorials/ex2.c.html
src/ksp/examples/tutorials/ex1.c.html
src/ksp/examples/tutorials/ex2.c.html
src/ksp/examples/tutorials/ex3.c.html
src/ksp/examples/tutorials/ex4.c.html
src/ksp/examples/tutorials/ex5.c.html
src/ksp/examples/tutorials/ex7.c.html
src/ksp/examples/tutorials/ex8.c.html