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Diffstat (limited to 'BLAS/SRC/dgemm.f')
| -rw-r--r-- | BLAS/SRC/dgemm.f | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/BLAS/SRC/dgemm.f b/BLAS/SRC/dgemm.f new file mode 100644 index 00000000..a154c125 --- /dev/null +++ b/BLAS/SRC/dgemm.f @@ -0,0 +1,313 @@ + SUBROUTINE DGEMM(TRANSA,TRANSB,M,N,K,ALPHA,A,LDA,B,LDB,BETA,C,LDC) +* .. Scalar Arguments .. + DOUBLE PRECISION ALPHA,BETA + INTEGER K,LDA,LDB,LDC,M,N + CHARACTER TRANSA,TRANSB +* .. +* .. Array Arguments .. + DOUBLE PRECISION A(LDA,*),B(LDB,*),C(LDC,*) +* .. +* +* Purpose +* ======= +* +* DGEMM performs one of the matrix-matrix operations +* +* C := alpha*op( A )*op( B ) + beta*C, +* +* where op( X ) is one of +* +* op( X ) = X or op( X ) = X', +* +* alpha and beta are scalars, and A, B and C are matrices, with op( A ) +* an m by k matrix, op( B ) a k by n matrix and C an m by n matrix. +* +* Arguments +* ========== +* +* TRANSA - CHARACTER*1. +* On entry, TRANSA specifies the form of op( A ) to be used in +* the matrix multiplication as follows: +* +* TRANSA = 'N' or 'n', op( A ) = A. +* +* TRANSA = 'T' or 't', op( A ) = A'. +* +* TRANSA = 'C' or 'c', op( A ) = A'. +* +* Unchanged on exit. +* +* TRANSB - CHARACTER*1. +* On entry, TRANSB specifies the form of op( B ) to be used in +* the matrix multiplication as follows: +* +* TRANSB = 'N' or 'n', op( B ) = B. +* +* TRANSB = 'T' or 't', op( B ) = B'. +* +* TRANSB = 'C' or 'c', op( B ) = B'. +* +* Unchanged on exit. +* +* M - INTEGER. +* On entry, M specifies the number of rows of the matrix +* op( A ) and of the matrix C. M must be at least zero. +* Unchanged on exit. +* +* N - INTEGER. +* On entry, N specifies the number of columns of the matrix +* op( B ) and the number of columns of the matrix C. N must be +* at least zero. +* Unchanged on exit. +* +* K - INTEGER. +* On entry, K specifies the number of columns of the matrix +* op( A ) and the number of rows of the matrix op( B ). K must +* be at least zero. +* Unchanged on exit. +* +* ALPHA - DOUBLE PRECISION. +* On entry, ALPHA specifies the scalar alpha. +* Unchanged on exit. +* +* A - DOUBLE PRECISION array of DIMENSION ( LDA, ka ), where ka is +* k when TRANSA = 'N' or 'n', and is m otherwise. +* Before entry with TRANSA = 'N' or 'n', the leading m by k +* part of the array A must contain the matrix A, otherwise +* the leading k by m part of the array A must contain the +* matrix A. +* Unchanged on exit. +* +* LDA - INTEGER. +* On entry, LDA specifies the first dimension of A as declared +* in the calling (sub) program. When TRANSA = 'N' or 'n' then +* LDA must be at least max( 1, m ), otherwise LDA must be at +* least max( 1, k ). +* Unchanged on exit. +* +* B - DOUBLE PRECISION array of DIMENSION ( LDB, kb ), where kb is +* n when TRANSB = 'N' or 'n', and is k otherwise. +* Before entry with TRANSB = 'N' or 'n', the leading k by n +* part of the array B must contain the matrix B, otherwise +* the leading n by k part of the array B must contain the +* matrix B. +* Unchanged on exit. +* +* LDB - INTEGER. +* On entry, LDB specifies the first dimension of B as declared +* in the calling (sub) program. When TRANSB = 'N' or 'n' then +* LDB must be at least max( 1, k ), otherwise LDB must be at +* least max( 1, n ). +* Unchanged on exit. +* +* BETA - DOUBLE PRECISION. +* On entry, BETA specifies the scalar beta. When BETA is +* supplied as zero then C need not be set on input. +* Unchanged on exit. +* +* C - DOUBLE PRECISION array of DIMENSION ( LDC, n ). +* Before entry, the leading m by n part of the array C must +* contain the matrix C, except when beta is zero, in which +* case C need not be set on entry. +* On exit, the array C is overwritten by the m by n matrix +* ( alpha*op( A )*op( B ) + beta*C ). +* +* LDC - INTEGER. +* On entry, LDC specifies the first dimension of C as declared +* in the calling (sub) program. LDC must be at least +* max( 1, m ). +* Unchanged on exit. +* +* +* Level 3 Blas routine. +* +* -- Written on 8-February-1989. +* Jack Dongarra, Argonne National Laboratory. +* Iain Duff, AERE Harwell. +* Jeremy Du Croz, Numerical Algorithms Group Ltd. +* Sven Hammarling, Numerical Algorithms Group Ltd. +* +* +* .. External Functions .. + LOGICAL LSAME + EXTERNAL LSAME +* .. +* .. External Subroutines .. + EXTERNAL XERBLA +* .. +* .. Intrinsic Functions .. + INTRINSIC MAX +* .. +* .. Local Scalars .. + DOUBLE PRECISION TEMP + INTEGER I,INFO,J,L,NCOLA,NROWA,NROWB + LOGICAL NOTA,NOTB +* .. +* .. Parameters .. + DOUBLE PRECISION ONE,ZERO + PARAMETER (ONE=1.0D+0,ZERO=0.0D+0) +* .. +* +* Set NOTA and NOTB as true if A and B respectively are not +* transposed and set NROWA, NCOLA and NROWB as the number of rows +* and columns of A and the number of rows of B respectively. +* + NOTA = LSAME(TRANSA,'N') + NOTB = LSAME(TRANSB,'N') + IF (NOTA) THEN + NROWA = M + NCOLA = K + ELSE + NROWA = K + NCOLA = M + END IF + IF (NOTB) THEN + NROWB = K + ELSE + NROWB = N + END IF +* +* Test the input parameters. +* + INFO = 0 + IF ((.NOT.NOTA) .AND. (.NOT.LSAME(TRANSA,'C')) .AND. + + (.NOT.LSAME(TRANSA,'T'))) THEN + INFO = 1 + ELSE IF ((.NOT.NOTB) .AND. (.NOT.LSAME(TRANSB,'C')) .AND. + + (.NOT.LSAME(TRANSB,'T'))) THEN + INFO = 2 + ELSE IF (M.LT.0) THEN + INFO = 3 + ELSE IF (N.LT.0) THEN + INFO = 4 + ELSE IF (K.LT.0) THEN + INFO = 5 + ELSE IF (LDA.LT.MAX(1,NROWA)) THEN + INFO = 8 + ELSE IF (LDB.LT.MAX(1,NROWB)) THEN + INFO = 10 + ELSE IF (LDC.LT.MAX(1,M)) THEN + INFO = 13 + END IF + IF (INFO.NE.0) THEN + CALL XERBLA('DGEMM ',INFO) + RETURN + END IF +* +* Quick return if possible. +* + IF ((M.EQ.0) .OR. (N.EQ.0) .OR. + + (((ALPHA.EQ.ZERO).OR. (K.EQ.0)).AND. (BETA.EQ.ONE))) RETURN +* +* And if alpha.eq.zero. +* + IF (ALPHA.EQ.ZERO) THEN + IF (BETA.EQ.ZERO) THEN + DO 20 J = 1,N + DO 10 I = 1,M + C(I,J) = ZERO + 10 CONTINUE + 20 CONTINUE + ELSE + DO 40 J = 1,N + DO 30 I = 1,M + C(I,J) = BETA*C(I,J) + 30 CONTINUE + 40 CONTINUE + END IF + RETURN + END IF +* +* Start the operations. +* + IF (NOTB) THEN + IF (NOTA) THEN +* +* Form C := alpha*A*B + beta*C. +* + DO 90 J = 1,N + IF (BETA.EQ.ZERO) THEN + DO 50 I = 1,M + C(I,J) = ZERO + 50 CONTINUE + ELSE IF (BETA.NE.ONE) THEN + DO 60 I = 1,M + C(I,J) = BETA*C(I,J) + 60 CONTINUE + END IF + DO 80 L = 1,K + IF (B(L,J).NE.ZERO) THEN + TEMP = ALPHA*B(L,J) + DO 70 I = 1,M + C(I,J) = C(I,J) + TEMP*A(I,L) + 70 CONTINUE + END IF + 80 CONTINUE + 90 CONTINUE + ELSE +* +* Form C := alpha*A'*B + beta*C +* + DO 120 J = 1,N + DO 110 I = 1,M + TEMP = ZERO + DO 100 L = 1,K + TEMP = TEMP + A(L,I)*B(L,J) + 100 CONTINUE + IF (BETA.EQ.ZERO) THEN + C(I,J) = ALPHA*TEMP + ELSE + C(I,J) = ALPHA*TEMP + BETA*C(I,J) + END IF + 110 CONTINUE + 120 CONTINUE + END IF + ELSE + IF (NOTA) THEN +* +* Form C := alpha*A*B' + beta*C +* + DO 170 J = 1,N + IF (BETA.EQ.ZERO) THEN + DO 130 I = 1,M + C(I,J) = ZERO + 130 CONTINUE + ELSE IF (BETA.NE.ONE) THEN + DO 140 I = 1,M + C(I,J) = BETA*C(I,J) + 140 CONTINUE + END IF + DO 160 L = 1,K + IF (B(J,L).NE.ZERO) THEN + TEMP = ALPHA*B(J,L) + DO 150 I = 1,M + C(I,J) = C(I,J) + TEMP*A(I,L) + 150 CONTINUE + END IF + 160 CONTINUE + 170 CONTINUE + ELSE +* +* Form C := alpha*A'*B' + beta*C +* + DO 200 J = 1,N + DO 190 I = 1,M + TEMP = ZERO + DO 180 L = 1,K + TEMP = TEMP + A(L,I)*B(J,L) + 180 CONTINUE + IF (BETA.EQ.ZERO) THEN + C(I,J) = ALPHA*TEMP + ELSE + C(I,J) = ALPHA*TEMP + BETA*C(I,J) + END IF + 190 CONTINUE + 200 CONTINUE + END IF + END IF +* + RETURN +* +* End of DGEMM . +* + END |