PSLASET(l) | LAPACK auxiliary routine (version 1.5) | PSLASET(l) |
NAME¶
PSLASET - initialize an M-by-N distributed matrix sub( A ) denoting A(IA:IA+M-1,JA:JA+N-1) to BETA on the diagonal and ALPHA on the offdiagonalsSYNOPSIS¶
- SUBROUTINE PSLASET(
- UPLO, M, N, ALPHA, BETA, A, IA, JA, DESCA )
- CHARACTER
- UPLO
- INTEGER
- IA, JA, M, N
- REAL
- ALPHA, BETA
- INTEGER
- DESCA( * )
- REAL
- A( * )
PURPOSE¶
PSLASET initializes an M-by-N distributed matrix sub( A ) denoting A(IA:IA+M-1,JA:JA+N-1) to BETA on the diagonal and ALPHA on the offdiagonals.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
ARGUMENTS¶
- UPLO (global input) CHARACTER
- Specifies the part of the distributed matrix sub( A ) to be
set:
- M (global input) INTEGER
- The number of rows to be operated on i.e the number of rows of the distributed submatrix sub( A ). M >= 0.
- N (global input) INTEGER
- The number of columns to be operated on i.e the number of columns of the distributed submatrix sub( A ). N >= 0.
- ALPHA (global input) REAL
- The constant to which the offdiagonal elements are to be set.
- BETA (global input) REAL
- The constant to which the diagonal elements are to be set.
- A (local output) REAL pointer into the local memory
- to an array of dimension (LLD_A,LOCc(JA+N-1)). This array
contains the local pieces of the distributed matrix sub( A ) to be set. On
exit, the leading M-by-N submatrix sub( A ) is set as follows:
- 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.
12 May 1997 | LAPACK version 1.5 |