1STRMM(1) BLAS routine STRMM(1)
2
6 STRMM - one of the matrix-matrix operations B := alpha*op( A )*B, or
7 B := alpha*B*op( A ),
8
10 SUBROUTINE STRMM(SIDE,UPLO,TRANSA,DIAG,M,N,ALPHA,A,LDA,B,LDB)
11 REAL ALPHA
13 INTEGER LDA,LDB,M,N
15 CHARACTER DIAG,SIDE,TRANSA,UPLO
17 REAL A(LDA,*),B(LDB,*)
19
21 STRMM performs one of the matrix-matrix operations
22 where alpha is a scalar, B is an m by n matrix, A is a unit, or
24 non-unit, upper or lower triangular matrix and op( A ) is one of
25 op( A ) = A or op( A ) = A'.
27
30 SIDE - CHARACTER*1.
31 On entry, SIDE specifies whether op( A ) multiplies B from the
32 left or right as follows:
33 SIDE = 'L' or 'l' B := alpha*op( A )*B.
35 SIDE = 'R' or 'r' B := alpha*B*op( A ).
37 Unchanged on exit.
39 UPLO - CHARACTER*1.
41 On entry, UPLO specifies whether the matrix A is an upper or
42 lower triangular matrix as follows:
43 UPLO = 'U' or 'u' A is an upper triangular matrix.
45 UPLO = 'L' or 'l' A is a lower triangular matrix.
47 Unchanged on exit.
49 TRANSA - CHARACTER*1. On entry, TRANSA specifies the form of
51 op( A ) to be used in the matrix multiplication as follows:
52 TRANSA = 'N' or 'n' op( A ) = A.
54 TRANSA = 'T' or 't' op( A ) = A'.
56 TRANSA = 'C' or 'c' op( A ) = A'.
58 Unchanged on exit.
60 DIAG - CHARACTER*1.
62 On entry, DIAG specifies whether or not A is unit triangular as
63 follows:
64 DIAG = 'U' or 'u' A is assumed to be unit triangular.
66 DIAG = 'N' or 'n' A is not assumed to be unit triangular.
68 Unchanged on exit.
70 M - INTEGER.
72 On entry, M specifies the number of rows of B. M must be at
73 least zero. Unchanged on exit.
74 N - INTEGER.
76 On entry, N specifies the number of columns of B. N must be at
77 least zero. Unchanged on exit.
78 ALPHA - REAL .
80 On entry, ALPHA specifies the scalar alpha. When alpha is
81 zero then A is not referenced and B need not be set before
82 entry. Unchanged on exit.
83 A - REAL array of DIMENSION ( LDA, k ), where k is m
85 when SIDE = 'L' or 'l' and is n when SIDE = 'R' or 'r'.
86 Before entry with UPLO = 'U' or 'u', the leading k by k
87 upper triangular part of the array A must contain the upper
88 triangular matrix and the strictly lower triangular part of A
89 is not referenced. Before entry with UPLO = 'L' or 'l', the
90 leading k by k lower triangular part of the array A must con‐
91 tain the lower triangular matrix and the strictly upper trian‐
92 gular part of A is not referenced. Note that when DIAG = 'U'
93 or 'u', the diagonal elements of A are not referenced either,
94 but are assumed to be unity. Unchanged on exit.
95 LDA - INTEGER.
97 On entry, LDA specifies the first dimension of A as declared in
98 the calling (sub) program. When SIDE = 'L' or 'l' then LDA
99 must be at least max( 1, m ), when SIDE = 'R' or 'r' then LDA
100 must be at least max( 1, n ). Unchanged on exit.
101 B - REAL array of DIMENSION ( LDB, n ).
103 Before entry, the leading m by n part of the array B must
104 contain the matrix B, and on exit is overwritten by the
105 transformed matrix.
106 LDB - INTEGER.
108 On entry, LDB specifies the first dimension of B as declared in
109 the calling (sub) program. LDB must be at least max( 1,
110 m ). Unchanged on exit.
111 Level 3 Blas routine.
113 -- Written on 8-February-1989. Jack Dongarra, Argonne National
115 Laboratory. Iain Duff, AERE Harwell. Jeremy Du Croz, Numerical
116 Algorithms Group Ltd. Sven Hammarling, Numerical Algorithms
117 Group Ltd.
118BLAS routine November 2006 STRMM(1)