1ZHEMM(1) BLAS routine ZHEMM(1)
2
6 ZHEMM - one of the matrix-matrix operations C := alpha*A*B + beta*C,
7
9 SUBROUTINE ZHEMM(SIDE,UPLO,M,N,ALPHA,A,LDA,B,LDB,BETA,C,LDC)
10 DOUBLE COMPLEX
12 ALPHA,BETA
13 INTEGER LDA,LDB,LDC,M,N
15 CHARACTER SIDE,UPLO
17 DOUBLE COMPLEX
19 A(LDA,*),B(LDB,*),C(LDC,*)
20
22 ZHEMM performs one of the matrix-matrix operations
23 or
25 C := alpha*B*A + beta*C,
27 where alpha and beta are scalars, A is an hermitian matrix and B and C
29 are m by n matrices.
30
33 SIDE - CHARACTER*1.
34 On entry, SIDE specifies whether the hermitian matrix A
35 appears on the left or right in the operation as follows:
36 SIDE = 'L' or 'l' C := alpha*A*B + beta*C,
38 SIDE = 'R' or 'r' C := alpha*B*A + beta*C,
40 Unchanged on exit.
42 UPLO - CHARACTER*1.
44 On entry, UPLO specifies whether the upper or lower
45 triangular part of the hermitian matrix A is to be
46 referenced as follows:
47 UPLO = 'U' or 'u' Only the upper triangular part of the her‐
49 mitian matrix is to be referenced.
50 UPLO = 'L' or 'l' Only the lower triangular part of the her‐
52 mitian matrix is to be referenced.
53 Unchanged on exit.
55 M - INTEGER.
57 On entry, M specifies the number of rows of the matrix C. M
58 must be at least zero. Unchanged on exit.
59 N - INTEGER.
61 On entry, N specifies the number of columns of the matrix C. N
62 must be at least zero. Unchanged on exit.
63 ALPHA - COMPLEX*16 .
65 On entry, ALPHA specifies the scalar alpha. Unchanged on exit.
66 A - COMPLEX*16 array of DIMENSION ( LDA, ka ), where ka is
68 m when SIDE = 'L' or 'l' and is n otherwise. Before entry
69 with SIDE = 'L' or 'l', the m by m part of the array A
70 must contain the hermitian matrix, such that when UPLO = 'U'
71 or 'u', the leading m by m upper triangular part of the array A
72 must contain the upper triangular part of the hermitian matrix
73 and the strictly lower triangular part of A is not refer‐
74 enced, and when UPLO = 'L' or 'l', the leading m by m lower
75 triangular part of the array A must contain the lower tri‐
76 angular part of the hermitian matrix and the strictly upper
77 triangular part of A is not referenced. Before entry with
78 SIDE = 'R' or 'r', the n by n part of the array A must con‐
79 tain the hermitian matrix, such that when UPLO = 'U' or 'u',
80 the leading n by n upper triangular part of the array A must
81 contain the upper triangular part of the hermitian matrix and
82 the strictly lower triangular part of A is not referenced,
83 and when UPLO = 'L' or 'l', the leading n by n lower triangu‐
84 lar part of the array A must contain the lower triangular
85 part of the hermitian matrix and the strictly upper triangu‐
86 lar part of A is not referenced. Note that the imaginary
87 parts of the diagonal elements need not be set, they are
88 assumed to be zero. Unchanged on exit.
89 LDA - INTEGER.
91 On entry, LDA specifies the first dimension of A as declared in
92 the calling (sub) program. When SIDE = 'L' or 'l' then LDA
93 must be at least max( 1, m ), otherwise LDA must be at least
94 max( 1, n ). Unchanged on exit.
95 B - COMPLEX*16 array of DIMENSION ( LDB, n ).
97 Before entry, the leading m by n part of the array B must
98 contain the matrix B. Unchanged on exit.
99 LDB - INTEGER.
101 On entry, LDB specifies the first dimension of B as declared in
102 the calling (sub) program. LDB must be at least max( 1,
103 m ). Unchanged on exit.
104 BETA - COMPLEX*16 .
106 On entry, BETA specifies the scalar beta. When BETA is
107 supplied as zero then C need not be set on input. Unchanged on
108 exit.
109 C - COMPLEX*16 array of DIMENSION ( LDC, n ).
111 Before entry, the leading m by n part of the array C must
112 contain the matrix C, except when beta is zero, in which
113 case C need not be set on entry. On exit, the array C is
114 overwritten by the m by n updated matrix.
115 LDC - INTEGER.
117 On entry, LDC specifies the first dimension of C as declared in
118 the calling (sub) program. LDC must be at least max( 1,
119 m ). Unchanged on exit.
120 Level 3 Blas routine.
122 -- Written on 8-February-1989. Jack Dongarra, Argonne National
124 Laboratory. Iain Duff, AERE Harwell. Jeremy Du Croz, Numerical
125 Algorithms Group Ltd. Sven Hammarling, Numerical Algorithms
126 Group Ltd.
127BLAS routine November 2006 ZHEMM(1)