**petsc-master 2020-07-04**

# MATKAIJ

MATKAIJ = "kaij" - A matrix type to be used to evaluate matrices of form [I \otimes S + A \otimes T], where S is a dense (p \times q) matrix, T is a dense (p \times q) matrix, A is an AIJ (n \times n) matrix, and I is the identity matrix. The resulting matrix is (np \times nq). S and T are always stored independently on all processes as PetscScalar arrays in column-major format.

### Notes

A linear system with multiple right-hand sides, AX = B, can be expressed in the KAIJ-friendly form of (A \otimes I) x = b,
where x and b are column vectors containing the row-major representations of X and B.

### See Also

MatKAIJSetAIJ(), MatKAIJSetS(), MatKAIJSetT(), MatKAIJGetAIJ(), MatKAIJGetS(), MatKAIJGetT(), MatCreateKAIJ()

### Level

advanced

### Location

src/mat/impls/kaij/kaij.c
### Examples

src/ksp/ksp/tutorials/ex74.c.html

src/ksp/ksp/tutorials/ex77.c.html

Index of all Mat routines

Table of Contents for all manual pages

Index of all manual pages