PSPOSV(l) | LAPACK routine (version 1.5) | PSPOSV(l) |

- SUBROUTINE PSPOSV(
- UPLO, N, NRHS, A, IA, JA, DESCA, B, IB, JB, DESCB, INFO )

sub( A ) = U**T * U, if UPLO = 'U', or

sub( A ) = L * L**T, if UPLO = 'L',

DTYPE_A = 1.

the BLACS process grid A is distribu-

ted over. The context itself is glo-

bal, but the handle (the integer

value) may vary.

array A.

array A.

the rows of the array.

the columns of the array.

row of the array A is distributed. CSRC_A (global) DESCA( CSRC_ ) The process column over which the

first column of the array A is

distributed.

array. LLD_A >= MAX(1,LOCr(M_A)).

LOCr( M ) = NUMROC( M, MB_A, MYROW, RSRC_A, NPROW ),

LOCc( N ) = NUMROC( N, NB_A, MYCOL, CSRC_A, NPCOL ). An upper bound for these quantities may be computed by:

LOCr( M ) <= ceil( ceil(M/MB_A)/NPROW )*MB_A

LOCc( N ) <= ceil( ceil(N/NB_A)/NPCOL )*NB_A

- UPLO (global input) CHARACTER
- = 'U': Upper triangle of sub( A ) is stored;

- N (global input) INTEGER
- The number of rows and columns to be operated on, i.e. the order of the distributed submatrix sub( A ). N >= 0.

- NRHS (global input) INTEGER
- The number of right hand sides, i.e., the number of columns of the distributed submatrix sub( B ). NRHS >= 0.

- A (local input/local output) REAL pointer into the
- local memory to an array of dimension (LLD_A, LOCc(JA+N-1)). On entry, this array contains the local pieces of the N-by-N symmetric distributed matrix sub( A ) to be factored. If UPLO = 'U', the leading N-by-N upper triangular part of sub( A ) contains the upper triangular part of the matrix, and its strictly lower triangular part is not referenced. If UPLO = 'L', the leading N-by-N lower triangular part of sub( A ) contains the lower triangular part of the distribu- ted matrix, and its strictly upper triangular part is not referenced. On exit, if INFO = 0, this array contains the local pieces of the factor U or L from the Cholesky factori- zation sub( A ) = U**T*U or L*L**T.

- IA (global input) INTEGER
- The row index in the global array A indicating the first row of sub( A ).

- JA (global input) INTEGER
- The column index in the global array A indicating the first column of sub( A ).

- DESCA (global and local input) INTEGER array of dimension DLEN_.
- The array descriptor for the distributed matrix A.

- B (local input/local output) REAL pointer into the
- local memory to an array of dimension (LLD_B,LOC(JB+NRHS-1)). On entry, the local pieces of the right hand sides distribu- ted matrix sub( B ). On exit, if INFO = 0, sub( B ) is over- written with the solution distributed matrix X.

- IB (global input) INTEGER
- The row index in the global array B indicating the first row of sub( B ).

- JB (global input) INTEGER
- The column index in the global array B indicating the first column of sub( B ).

- DESCB (global and local input) INTEGER array of dimension DLEN_.
- The array descriptor for the distributed matrix B.

- INFO (global output) INTEGER
- = 0: successful exit

12 May 1997 | LAPACK version 1.5 |