1STRMM(1) BLAS routine STRMM(1)
2
6 STRMM - performs one of the matrix-matrix operations B := alpha*op( A
7 )*B, or 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
113 Level 3 Blas routine.
114 -- Written on 8-February-1989.
116 Jack Dongarra, Argonne National Laboratory.
117 Iain Duff, AERE Harwell.
118 Jeremy Du Croz, Numerical Algorithms Group Ltd.
119 Sven Hammarling, Numerical Algorithms Group Ltd.
120BLAS routine November 2008 STRMM(1)