root / src / blas / zhemm.f @ 4
Historique | Voir | Annoter | Télécharger (9,61 ko)
| 1 |
SUBROUTINE ZHEMM(SIDE,UPLO,M,N,ALPHA,A,LDA,B,LDB,BETA,C,LDC) |
|---|---|
| 2 |
* .. Scalar Arguments .. |
| 3 |
DOUBLE COMPLEX ALPHA,BETA |
| 4 |
INTEGER LDA,LDB,LDC,M,N |
| 5 |
CHARACTER SIDE,UPLO |
| 6 |
* .. |
| 7 |
* .. Array Arguments .. |
| 8 |
DOUBLE COMPLEX A(LDA,*),B(LDB,*),C(LDC,*) |
| 9 |
* .. |
| 10 |
* |
| 11 |
* Purpose |
| 12 |
* ======= |
| 13 |
* |
| 14 |
* ZHEMM performs one of the matrix-matrix operations |
| 15 |
* |
| 16 |
* C := alpha*A*B + beta*C, |
| 17 |
* |
| 18 |
* or |
| 19 |
* |
| 20 |
* C := alpha*B*A + beta*C, |
| 21 |
* |
| 22 |
* where alpha and beta are scalars, A is an hermitian matrix and B and |
| 23 |
* C are m by n matrices. |
| 24 |
* |
| 25 |
* Arguments |
| 26 |
* ========== |
| 27 |
* |
| 28 |
* SIDE - CHARACTER*1. |
| 29 |
* On entry, SIDE specifies whether the hermitian matrix A |
| 30 |
* appears on the left or right in the operation as follows: |
| 31 |
* |
| 32 |
* SIDE = 'L' or 'l' C := alpha*A*B + beta*C, |
| 33 |
* |
| 34 |
* SIDE = 'R' or 'r' C := alpha*B*A + beta*C, |
| 35 |
* |
| 36 |
* Unchanged on exit. |
| 37 |
* |
| 38 |
* UPLO - CHARACTER*1. |
| 39 |
* On entry, UPLO specifies whether the upper or lower |
| 40 |
* triangular part of the hermitian matrix A is to be |
| 41 |
* referenced as follows: |
| 42 |
* |
| 43 |
* UPLO = 'U' or 'u' Only the upper triangular part of the |
| 44 |
* hermitian matrix is to be referenced. |
| 45 |
* |
| 46 |
* UPLO = 'L' or 'l' Only the lower triangular part of the |
| 47 |
* hermitian matrix is to be referenced. |
| 48 |
* |
| 49 |
* Unchanged on exit. |
| 50 |
* |
| 51 |
* M - INTEGER. |
| 52 |
* On entry, M specifies the number of rows of the matrix C. |
| 53 |
* M must be at least zero. |
| 54 |
* Unchanged on exit. |
| 55 |
* |
| 56 |
* N - INTEGER. |
| 57 |
* On entry, N specifies the number of columns of the matrix C. |
| 58 |
* N must be at least zero. |
| 59 |
* Unchanged on exit. |
| 60 |
* |
| 61 |
* ALPHA - COMPLEX*16 . |
| 62 |
* On entry, ALPHA specifies the scalar alpha. |
| 63 |
* Unchanged on exit. |
| 64 |
* |
| 65 |
* A - COMPLEX*16 array of DIMENSION ( LDA, ka ), where ka is |
| 66 |
* m when SIDE = 'L' or 'l' and is n otherwise. |
| 67 |
* Before entry with SIDE = 'L' or 'l', the m by m part of |
| 68 |
* the array A must contain the hermitian matrix, such that |
| 69 |
* when UPLO = 'U' or 'u', the leading m by m upper triangular |
| 70 |
* part of the array A must contain the upper triangular part |
| 71 |
* of the hermitian matrix and the strictly lower triangular |
| 72 |
* part of A is not referenced, and when UPLO = 'L' or 'l', |
| 73 |
* the leading m by m lower triangular part of the array A |
| 74 |
* must contain the lower triangular part of the hermitian |
| 75 |
* matrix and the strictly upper triangular part of A is not |
| 76 |
* referenced. |
| 77 |
* Before entry with SIDE = 'R' or 'r', the n by n part of |
| 78 |
* the array A must contain the hermitian matrix, such that |
| 79 |
* when UPLO = 'U' or 'u', the leading n by n upper triangular |
| 80 |
* part of the array A must contain the upper triangular part |
| 81 |
* of the hermitian matrix and the strictly lower triangular |
| 82 |
* part of A is not referenced, and when UPLO = 'L' or 'l', |
| 83 |
* the leading n by n lower triangular part of the array A |
| 84 |
* must contain the lower triangular part of the hermitian |
| 85 |
* matrix and the strictly upper triangular part of A is not |
| 86 |
* referenced. |
| 87 |
* Note that the imaginary parts of the diagonal elements need |
| 88 |
* not be set, they are assumed to be zero. |
| 89 |
* Unchanged on exit. |
| 90 |
* |
| 91 |
* LDA - INTEGER. |
| 92 |
* On entry, LDA specifies the first dimension of A as declared |
| 93 |
* in the calling (sub) program. When SIDE = 'L' or 'l' then |
| 94 |
* LDA must be at least max( 1, m ), otherwise LDA must be at |
| 95 |
* least max( 1, n ). |
| 96 |
* Unchanged on exit. |
| 97 |
* |
| 98 |
* B - COMPLEX*16 array of DIMENSION ( LDB, n ). |
| 99 |
* Before entry, the leading m by n part of the array B must |
| 100 |
* contain the matrix B. |
| 101 |
* Unchanged on exit. |
| 102 |
* |
| 103 |
* LDB - INTEGER. |
| 104 |
* On entry, LDB specifies the first dimension of B as declared |
| 105 |
* in the calling (sub) program. LDB must be at least |
| 106 |
* max( 1, m ). |
| 107 |
* Unchanged on exit. |
| 108 |
* |
| 109 |
* BETA - COMPLEX*16 . |
| 110 |
* On entry, BETA specifies the scalar beta. When BETA is |
| 111 |
* supplied as zero then C need not be set on input. |
| 112 |
* Unchanged on exit. |
| 113 |
* |
| 114 |
* C - COMPLEX*16 array of DIMENSION ( LDC, n ). |
| 115 |
* Before entry, the leading m by n part of the array C must |
| 116 |
* contain the matrix C, except when beta is zero, in which |
| 117 |
* case C need not be set on entry. |
| 118 |
* On exit, the array C is overwritten by the m by n updated |
| 119 |
* matrix. |
| 120 |
* |
| 121 |
* LDC - INTEGER. |
| 122 |
* On entry, LDC specifies the first dimension of C as declared |
| 123 |
* in the calling (sub) program. LDC must be at least |
| 124 |
* max( 1, m ). |
| 125 |
* Unchanged on exit. |
| 126 |
* |
| 127 |
* |
| 128 |
* Level 3 Blas routine. |
| 129 |
* |
| 130 |
* -- Written on 8-February-1989. |
| 131 |
* Jack Dongarra, Argonne National Laboratory. |
| 132 |
* Iain Duff, AERE Harwell. |
| 133 |
* Jeremy Du Croz, Numerical Algorithms Group Ltd. |
| 134 |
* Sven Hammarling, Numerical Algorithms Group Ltd. |
| 135 |
* |
| 136 |
* |
| 137 |
* .. External Functions .. |
| 138 |
LOGICAL LSAME |
| 139 |
EXTERNAL LSAME |
| 140 |
* .. |
| 141 |
* .. External Subroutines .. |
| 142 |
EXTERNAL XERBLA |
| 143 |
* .. |
| 144 |
* .. Intrinsic Functions .. |
| 145 |
INTRINSIC DBLE,DCONJG,MAX |
| 146 |
* .. |
| 147 |
* .. Local Scalars .. |
| 148 |
DOUBLE COMPLEX TEMP1,TEMP2 |
| 149 |
INTEGER I,INFO,J,K,NROWA |
| 150 |
LOGICAL UPPER |
| 151 |
* .. |
| 152 |
* .. Parameters .. |
| 153 |
DOUBLE COMPLEX ONE |
| 154 |
PARAMETER (ONE= (1.0D+0,0.0D+0)) |
| 155 |
DOUBLE COMPLEX ZERO |
| 156 |
PARAMETER (ZERO= (0.0D+0,0.0D+0)) |
| 157 |
* .. |
| 158 |
* |
| 159 |
* Set NROWA as the number of rows of A. |
| 160 |
* |
| 161 |
IF (LSAME(SIDE,'L')) THEN |
| 162 |
NROWA = M |
| 163 |
ELSE |
| 164 |
NROWA = N |
| 165 |
END IF |
| 166 |
UPPER = LSAME(UPLO,'U') |
| 167 |
* |
| 168 |
* Test the input parameters. |
| 169 |
* |
| 170 |
INFO = 0 |
| 171 |
IF ((.NOT.LSAME(SIDE,'L')) .AND. (.NOT.LSAME(SIDE,'R'))) THEN |
| 172 |
INFO = 1 |
| 173 |
ELSE IF ((.NOT.UPPER) .AND. (.NOT.LSAME(UPLO,'L'))) THEN |
| 174 |
INFO = 2 |
| 175 |
ELSE IF (M.LT.0) THEN |
| 176 |
INFO = 3 |
| 177 |
ELSE IF (N.LT.0) THEN |
| 178 |
INFO = 4 |
| 179 |
ELSE IF (LDA.LT.MAX(1,NROWA)) THEN |
| 180 |
INFO = 7 |
| 181 |
ELSE IF (LDB.LT.MAX(1,M)) THEN |
| 182 |
INFO = 9 |
| 183 |
ELSE IF (LDC.LT.MAX(1,M)) THEN |
| 184 |
INFO = 12 |
| 185 |
END IF |
| 186 |
IF (INFO.NE.0) THEN |
| 187 |
CALL XERBLA('ZHEMM ',INFO)
|
| 188 |
RETURN |
| 189 |
END IF |
| 190 |
* |
| 191 |
* Quick return if possible. |
| 192 |
* |
| 193 |
IF ((M.EQ.0) .OR. (N.EQ.0) .OR. |
| 194 |
+ ((ALPHA.EQ.ZERO).AND. (BETA.EQ.ONE))) RETURN |
| 195 |
* |
| 196 |
* And when alpha.eq.zero. |
| 197 |
* |
| 198 |
IF (ALPHA.EQ.ZERO) THEN |
| 199 |
IF (BETA.EQ.ZERO) THEN |
| 200 |
DO 20 J = 1,N |
| 201 |
DO 10 I = 1,M |
| 202 |
C(I,J) = ZERO |
| 203 |
10 CONTINUE |
| 204 |
20 CONTINUE |
| 205 |
ELSE |
| 206 |
DO 40 J = 1,N |
| 207 |
DO 30 I = 1,M |
| 208 |
C(I,J) = BETA*C(I,J) |
| 209 |
30 CONTINUE |
| 210 |
40 CONTINUE |
| 211 |
END IF |
| 212 |
RETURN |
| 213 |
END IF |
| 214 |
* |
| 215 |
* Start the operations. |
| 216 |
* |
| 217 |
IF (LSAME(SIDE,'L')) THEN |
| 218 |
* |
| 219 |
* Form C := alpha*A*B + beta*C. |
| 220 |
* |
| 221 |
IF (UPPER) THEN |
| 222 |
DO 70 J = 1,N |
| 223 |
DO 60 I = 1,M |
| 224 |
TEMP1 = ALPHA*B(I,J) |
| 225 |
TEMP2 = ZERO |
| 226 |
DO 50 K = 1,I - 1 |
| 227 |
C(K,J) = C(K,J) + TEMP1*A(K,I) |
| 228 |
TEMP2 = TEMP2 + B(K,J)*DCONJG(A(K,I)) |
| 229 |
50 CONTINUE |
| 230 |
IF (BETA.EQ.ZERO) THEN |
| 231 |
C(I,J) = TEMP1*DBLE(A(I,I)) + ALPHA*TEMP2 |
| 232 |
ELSE |
| 233 |
C(I,J) = BETA*C(I,J) + TEMP1*DBLE(A(I,I)) + |
| 234 |
+ ALPHA*TEMP2 |
| 235 |
END IF |
| 236 |
60 CONTINUE |
| 237 |
70 CONTINUE |
| 238 |
ELSE |
| 239 |
DO 100 J = 1,N |
| 240 |
DO 90 I = M,1,-1 |
| 241 |
TEMP1 = ALPHA*B(I,J) |
| 242 |
TEMP2 = ZERO |
| 243 |
DO 80 K = I + 1,M |
| 244 |
C(K,J) = C(K,J) + TEMP1*A(K,I) |
| 245 |
TEMP2 = TEMP2 + B(K,J)*DCONJG(A(K,I)) |
| 246 |
80 CONTINUE |
| 247 |
IF (BETA.EQ.ZERO) THEN |
| 248 |
C(I,J) = TEMP1*DBLE(A(I,I)) + ALPHA*TEMP2 |
| 249 |
ELSE |
| 250 |
C(I,J) = BETA*C(I,J) + TEMP1*DBLE(A(I,I)) + |
| 251 |
+ ALPHA*TEMP2 |
| 252 |
END IF |
| 253 |
90 CONTINUE |
| 254 |
100 CONTINUE |
| 255 |
END IF |
| 256 |
ELSE |
| 257 |
* |
| 258 |
* Form C := alpha*B*A + beta*C. |
| 259 |
* |
| 260 |
DO 170 J = 1,N |
| 261 |
TEMP1 = ALPHA*DBLE(A(J,J)) |
| 262 |
IF (BETA.EQ.ZERO) THEN |
| 263 |
DO 110 I = 1,M |
| 264 |
C(I,J) = TEMP1*B(I,J) |
| 265 |
110 CONTINUE |
| 266 |
ELSE |
| 267 |
DO 120 I = 1,M |
| 268 |
C(I,J) = BETA*C(I,J) + TEMP1*B(I,J) |
| 269 |
120 CONTINUE |
| 270 |
END IF |
| 271 |
DO 140 K = 1,J - 1 |
| 272 |
IF (UPPER) THEN |
| 273 |
TEMP1 = ALPHA*A(K,J) |
| 274 |
ELSE |
| 275 |
TEMP1 = ALPHA*DCONJG(A(J,K)) |
| 276 |
END IF |
| 277 |
DO 130 I = 1,M |
| 278 |
C(I,J) = C(I,J) + TEMP1*B(I,K) |
| 279 |
130 CONTINUE |
| 280 |
140 CONTINUE |
| 281 |
DO 160 K = J + 1,N |
| 282 |
IF (UPPER) THEN |
| 283 |
TEMP1 = ALPHA*DCONJG(A(J,K)) |
| 284 |
ELSE |
| 285 |
TEMP1 = ALPHA*A(K,J) |
| 286 |
END IF |
| 287 |
DO 150 I = 1,M |
| 288 |
C(I,J) = C(I,J) + TEMP1*B(I,K) |
| 289 |
150 CONTINUE |
| 290 |
160 CONTINUE |
| 291 |
170 CONTINUE |
| 292 |
END IF |
| 293 |
* |
| 294 |
RETURN |
| 295 |
* |
| 296 |
* End of ZHEMM . |
| 297 |
* |
| 298 |
END |