Note: this is a BLAS routine and is not in libslatec.a
*DECK DTRSM
SUBROUTINE DTRSM (SIDE, UPLO, TRANSA, DIAG, M, N, ALPHA, A, LDA,
$ B, LDB)
C***BEGIN PROLOGUE DTRSM
C***PURPOSE Solve one of the matrix equations.
C***LIBRARY SLATEC (BLAS)
C***CATEGORY D1B6
C***TYPE DOUBLE PRECISION (STRSM-S, DTRSM-D, CTRSM-C)
C***KEYWORDS LEVEL 3 BLAS, LINEAR ALGEBRA
C***AUTHOR Dongarra, J., (ANL)
C Duff, I., (AERE)
C Du Croz, J., (NAG)
C Hammarling, S. (NAG)
C***DESCRIPTION
C
C DTRSM solves one of the matrix equations
C
C op( A )*X = alpha*B, or X*op( A ) = alpha*B,
C
C where alpha is a scalar, X and B are m by n matrices, A is a unit, or
C non-unit, upper or lower triangular matrix and op( A ) is one of
C
C op( A ) = A or op( A ) = A'.
C
C The matrix X is overwritten on B.
C
C Parameters
C ==========
C
C SIDE - CHARACTER*1.
C On entry, SIDE specifies whether op( A ) appears on the left
C or right of X as follows:
C
C SIDE = 'L' or 'l' op( A )*X = alpha*B.
C
C SIDE = 'R' or 'r' X*op( A ) = alpha*B.
C
C Unchanged on exit.
C
C UPLO - CHARACTER*1.
C On entry, UPLO specifies whether the matrix A is an upper or
C lower triangular matrix as follows:
C
C UPLO = 'U' or 'u' A is an upper triangular matrix.
C
C UPLO = 'L' or 'l' A is a lower triangular matrix.
C
C Unchanged on exit.
C
C TRANSA - CHARACTER*1.
C On entry, TRANSA specifies the form of op( A ) to be used in
C the matrix multiplication as follows:
C
C TRANSA = 'N' or 'n' op( A ) = A.
C
C TRANSA = 'T' or 't' op( A ) = A'.
C
C TRANSA = 'C' or 'c' op( A ) = A'.
C
C Unchanged on exit.
C
C DIAG - CHARACTER*1.
C On entry, DIAG specifies whether or not A is unit triangular
C as follows:
C
C DIAG = 'U' or 'u' A is assumed to be unit triangular.
C
C DIAG = 'N' or 'n' A is not assumed to be unit
C triangular.
C
C Unchanged on exit.
C
C M - INTEGER.
C On entry, M specifies the number of rows of B. M must be at
C least zero.
C Unchanged on exit.
C
C N - INTEGER.
C On entry, N specifies the number of columns of B. N must be
C at least zero.
C Unchanged on exit.
C
C ALPHA - DOUBLE PRECISION.
C On entry, ALPHA specifies the scalar alpha. When alpha is
C zero then A is not referenced and B need not be set before
C entry.
C Unchanged on exit.
C
C A - DOUBLE PRECISION array of DIMENSION ( LDA, k ), where k is m
C when SIDE = 'L' or 'l' and is n when SIDE = 'R' or 'r'.
C Before entry with UPLO = 'U' or 'u', the leading k by k
C upper triangular part of the array A must contain the upper
C triangular matrix and the strictly lower triangular part of
C A is not referenced.
C Before entry with UPLO = 'L' or 'l', the leading k by k
C lower triangular part of the array A must contain the lower
C triangular matrix and the strictly upper triangular part of
C A is not referenced.
C Note that when DIAG = 'U' or 'u', the diagonal elements of
C A are not referenced either, but are assumed to be unity.
C Unchanged on exit.
C
C LDA - INTEGER.
C On entry, LDA specifies the first dimension of A as declared
C in the calling (sub) program. When SIDE = 'L' or 'l' then
C LDA must be at least max( 1, m ), when SIDE = 'R' or 'r'
C then LDA must be at least max( 1, n ).
C Unchanged on exit.
C
C B - DOUBLE PRECISION array of DIMENSION ( LDB, n ).
C Before entry, the leading m by n part of the array B must
C contain the right-hand side matrix B, and on exit is
C overwritten by the solution matrix X.
C
C LDB - INTEGER.
C On entry, LDB specifies the first dimension of B as declared
C in the calling (sub) program. LDB must be at least
C max( 1, m ).
C Unchanged on exit.
C
C***REFERENCES Dongarra, J., Du Croz, J., Duff, I., and Hammarling, S.
C A set of level 3 basic linear algebra subprograms.
C ACM TOMS, Vol. 16, No. 1, pp. 1-17, March 1990.
C***ROUTINES CALLED LSAME, XERBLA
C***REVISION HISTORY (YYMMDD)
C 890208 DATE WRITTEN
C 910605 Modified to meet SLATEC prologue standards. Only comment
C lines were modified. (BKS)
C***END PROLOGUE DTRSM