1CHEMM(1) BLAS routine CHEMM(1)
2
6 CHEMM - one of the matrix-matrix operations C := alpha*A*B + beta*C,
7
9 SUBROUTINE CHEMM(SIDE,UPLO,M,N,ALPHA,A,LDA,B,LDB,BETA,C,LDC)
10 COMPLEX ALPHA,BETA
12 INTEGER LDA,LDB,LDC,M,N
14 CHARACTER SIDE,UPLO
16 COMPLEX A(LDA,*),B(LDB,*),C(LDC,*)
18
20 CHEMM performs one of the matrix-matrix operations
21 or
23 C := alpha*B*A + beta*C,
25 where alpha and beta are scalars, A is an hermitian matrix and B and C
27 are m by n matrices.
28
31 SIDE - CHARACTER*1.
32 On entry, SIDE specifies whether the hermitian matrix A
33 appears on the left or right in the operation as follows:
34 SIDE = 'L' or 'l' C := alpha*A*B + beta*C,
36 SIDE = 'R' or 'r' C := alpha*B*A + beta*C,
38 Unchanged on exit.
40 UPLO - CHARACTER*1.
42 On entry, UPLO specifies whether the upper or lower
43 triangular part of the hermitian matrix A is to be
44 referenced as follows:
45 UPLO = 'U' or 'u' Only the upper triangular part of the her‐
47 mitian matrix is to be referenced.
48 UPLO = 'L' or 'l' Only the lower triangular part of the her‐
50 mitian matrix is to be referenced.
51 Unchanged on exit.
53 M - INTEGER.
55 On entry, M specifies the number of rows of the matrix C. M
56 must be at least zero. Unchanged on exit.
57 N - INTEGER.
59 On entry, N specifies the number of columns of the matrix C. N
60 must be at least zero. Unchanged on exit.
61 ALPHA - COMPLEX .
63 On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
64 A - COMPLEX array of DIMENSION ( LDA, ka ), where ka is
66 m when SIDE = 'L' or 'l' and is n otherwise. Before entry
67 with SIDE = 'L' or 'l', the m by m part of the array A
68 must contain the hermitian matrix, such that when UPLO = 'U'
69 or 'u', the leading m by m upper triangular part of the array A
70 must contain the upper triangular part of the hermitian matrix
71 and the strictly lower triangular part of A is not refer‐
72 enced, and when UPLO = 'L' or 'l', the leading m by m lower
73 triangular part of the array A must contain the lower tri‐
74 angular part of the hermitian matrix and the strictly upper
75 triangular part of A is not referenced. Before entry with
76 SIDE = 'R' or 'r', the n by n part of the array A must con‐
77 tain the hermitian matrix, such that when UPLO = 'U' or 'u',
78 the leading n by n upper triangular part of the array A must
79 contain the upper triangular part of the hermitian matrix and
80 the strictly lower triangular part of A is not referenced,
81 and when UPLO = 'L' or 'l', the leading n by n lower triangu‐
82 lar part of the array A must contain the lower triangular
83 part of the hermitian matrix and the strictly upper triangu‐
84 lar part of A is not referenced. Note that the imaginary
85 parts of the diagonal elements need not be set, they are
86 assumed to be zero. Unchanged on exit.
87 LDA - INTEGER.
89 On entry, LDA specifies the first dimension of A as declared in
90 the calling (sub) program. When SIDE = 'L' or 'l' then LDA
91 must be at least max( 1, m ), otherwise LDA must be at least
92 max( 1, n ). Unchanged on exit.
93 B - COMPLEX array of DIMENSION ( LDB, n ).
95 Before entry, the leading m by n part of the array B must
96 contain the matrix B. Unchanged on exit.
97 LDB - INTEGER.
99 On entry, LDB specifies the first dimension of B as declared in
100 the calling (sub) program. LDB must be at least max( 1,
101 m ). Unchanged on exit.
102 BETA - COMPLEX .
104 On entry, BETA specifies the scalar beta. When BETA is
105 supplied as zero then C need not be set on input. Unchanged on
106 exit.
107 C - COMPLEX array of DIMENSION ( LDC, n ).
109 Before entry, the leading m by n part of the array C must
110 contain the matrix C, except when beta is zero, in which
111 case C need not be set on entry. On exit, the array C is
112 overwritten by the m by n updated matrix.
113 LDC - INTEGER.
115 On entry, LDC specifies the first dimension of C as declared in
116 the calling (sub) program. LDC must be at least max( 1,
117 m ). Unchanged on exit.
118 Level 3 Blas routine.
120 -- Written on 8-February-1989. Jack Dongarra, Argonne National
122 Laboratory. Iain Duff, AERE Harwell. Jeremy Du Croz, Numerical
123 Algorithms Group Ltd. Sven Hammarling, Numerical Algorithms
124 Group Ltd.
125BLAS routine November 2006 CHEMM(1)