diff options
Diffstat (limited to 'src/fortran/blas/zhemm.f')
| -rw-r--r-- | src/fortran/blas/zhemm.f | 304 |
1 files changed, 304 insertions, 0 deletions
diff --git a/src/fortran/blas/zhemm.f b/src/fortran/blas/zhemm.f new file mode 100644 index 0000000..d3912c0 --- /dev/null +++ b/src/fortran/blas/zhemm.f @@ -0,0 +1,304 @@ + SUBROUTINE ZHEMM ( SIDE, UPLO, M, N, ALPHA, A, LDA, B, LDB, + $ BETA, C, LDC ) +* .. Scalar Arguments .. + CHARACTER*1 SIDE, UPLO + INTEGER M, N, LDA, LDB, LDC + COMPLEX*16 ALPHA, BETA +* .. Array Arguments .. + COMPLEX*16 A( LDA, * ), B( LDB, * ), C( LDC, * ) +* .. +* +* Purpose +* ======= +* +* ZHEMM performs one of the matrix-matrix operations +* +* C := alpha*A*B + beta*C, +* +* or +* +* C := alpha*B*A + beta*C, +* +* where alpha and beta are scalars, A is an hermitian matrix and B and +* C are m by n matrices. +* +* Parameters +* ========== +* +* SIDE - CHARACTER*1. +* On entry, SIDE specifies whether the hermitian matrix A +* appears on the left or right in the operation as follows: +* +* SIDE = 'L' or 'l' C := alpha*A*B + beta*C, +* +* SIDE = 'R' or 'r' C := alpha*B*A + beta*C, +* +* Unchanged on exit. +* +* UPLO - CHARACTER*1. +* On entry, UPLO specifies whether the upper or lower +* triangular part of the hermitian matrix A is to be +* referenced as follows: +* +* UPLO = 'U' or 'u' Only the upper triangular part of the +* hermitian matrix is to be referenced. +* +* UPLO = 'L' or 'l' Only the lower triangular part of the +* hermitian matrix is to be referenced. +* +* Unchanged on exit. +* +* M - INTEGER. +* On entry, M specifies the number of rows 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 C. +* N must be at least zero. +* Unchanged on exit. +* +* ALPHA - COMPLEX*16 . +* On entry, ALPHA specifies the scalar alpha. +* Unchanged on exit. +* +* A - COMPLEX*16 array of DIMENSION ( LDA, ka ), where ka is +* m when SIDE = 'L' or 'l' and is n otherwise. +* Before entry with SIDE = 'L' or 'l', the m by m part of +* the array A must contain the hermitian matrix, such that +* when UPLO = 'U' or 'u', the leading m by m upper triangular +* part of the array A must contain the upper triangular part +* of the hermitian matrix and the strictly lower triangular +* part of A is not referenced, and when UPLO = 'L' or 'l', +* the leading m by m lower triangular part of the array A +* must contain the lower triangular part of the hermitian +* matrix and the strictly upper triangular part of A is not +* referenced. +* Before entry with SIDE = 'R' or 'r', the n by n part of +* the array A must contain the hermitian matrix, such that +* when UPLO = 'U' or 'u', the leading n by n upper triangular +* part of the array A must contain the upper triangular part +* of the hermitian matrix and the strictly lower triangular +* part of A is not referenced, and when UPLO = 'L' or 'l', +* the leading n by n lower triangular part of the array A +* must contain the lower triangular part of the hermitian +* matrix and the strictly upper triangular part of A is not +* referenced. +* Note that the imaginary parts of the diagonal elements need +* not be set, they are assumed to be zero. +* Unchanged on exit. +* +* LDA - INTEGER. +* On entry, LDA specifies the first dimension of A as declared +* in the calling (sub) program. When SIDE = 'L' or 'l' then +* LDA must be at least max( 1, m ), otherwise LDA must be at +* least max( 1, n ). +* Unchanged on exit. +* +* B - COMPLEX*16 array of DIMENSION ( LDB, n ). +* Before entry, the leading m by n 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. LDB must be at least +* max( 1, m ). +* Unchanged on exit. +* +* BETA - COMPLEX*16 . +* 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 - COMPLEX*16 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 updated +* matrix. +* +* 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 DCONJG, MAX, DBLE +* .. Local Scalars .. + LOGICAL UPPER + INTEGER I, INFO, J, K, NROWA + COMPLEX*16 TEMP1, TEMP2 +* .. Parameters .. + COMPLEX*16 ONE + PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ) ) + COMPLEX*16 ZERO + PARAMETER ( ZERO = ( 0.0D+0, 0.0D+0 ) ) +* .. +* .. Executable Statements .. +* +* Set NROWA as the number of rows of A. +* + IF( LSAME( SIDE, 'L' ) )THEN + NROWA = M + ELSE + NROWA = N + END IF + UPPER = LSAME( UPLO, 'U' ) +* +* Test the input parameters. +* + INFO = 0 + IF( ( .NOT.LSAME( SIDE, 'L' ) ).AND. + $ ( .NOT.LSAME( SIDE, 'R' ) ) )THEN + INFO = 1 + ELSE IF( ( .NOT.UPPER ).AND. + $ ( .NOT.LSAME( UPLO, 'L' ) ) )THEN + INFO = 2 + ELSE IF( M .LT.0 )THEN + INFO = 3 + ELSE IF( N .LT.0 )THEN + INFO = 4 + ELSE IF( LDA.LT.MAX( 1, NROWA ) )THEN + INFO = 7 + ELSE IF( LDB.LT.MAX( 1, M ) )THEN + INFO = 9 + ELSE IF( LDC.LT.MAX( 1, M ) )THEN + INFO = 12 + END IF + IF( INFO.NE.0 )THEN + CALL XERBLA( 'ZHEMM ', INFO ) + RETURN + END IF +* +* Quick return if possible. +* + IF( ( M.EQ.0 ).OR.( N.EQ.0 ).OR. + $ ( ( ALPHA.EQ.ZERO ).AND.( BETA.EQ.ONE ) ) ) + $ RETURN +* +* And when 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( LSAME( SIDE, 'L' ) )THEN +* +* Form C := alpha*A*B + beta*C. +* + IF( UPPER )THEN + DO 70, J = 1, N + DO 60, I = 1, M + TEMP1 = ALPHA*B( I, J ) + TEMP2 = ZERO + DO 50, K = 1, I - 1 + C( K, J ) = C( K, J ) + TEMP1*A( K, I ) + TEMP2 = TEMP2 + + $ B( K, J )*DCONJG( A( K, I ) ) + 50 CONTINUE + IF( BETA.EQ.ZERO )THEN + C( I, J ) = TEMP1*DBLE( A( I, I ) ) + + $ ALPHA*TEMP2 + ELSE + C( I, J ) = BETA *C( I, J ) + + $ TEMP1*DBLE( A( I, I ) ) + + $ ALPHA*TEMP2 + END IF + 60 CONTINUE + 70 CONTINUE + ELSE + DO 100, J = 1, N + DO 90, I = M, 1, -1 + TEMP1 = ALPHA*B( I, J ) + TEMP2 = ZERO + DO 80, K = I + 1, M + C( K, J ) = C( K, J ) + TEMP1*A( K, I ) + TEMP2 = TEMP2 + + $ B( K, J )*DCONJG( A( K, I ) ) + 80 CONTINUE + IF( BETA.EQ.ZERO )THEN + C( I, J ) = TEMP1*DBLE( A( I, I ) ) + + $ ALPHA*TEMP2 + ELSE + C( I, J ) = BETA *C( I, J ) + + $ TEMP1*DBLE( A( I, I ) ) + + $ ALPHA*TEMP2 + END IF + 90 CONTINUE + 100 CONTINUE + END IF + ELSE +* +* Form C := alpha*B*A + beta*C. +* + DO 170, J = 1, N + TEMP1 = ALPHA*DBLE( A( J, J ) ) + IF( BETA.EQ.ZERO )THEN + DO 110, I = 1, M + C( I, J ) = TEMP1*B( I, J ) + 110 CONTINUE + ELSE + DO 120, I = 1, M + C( I, J ) = BETA*C( I, J ) + TEMP1*B( I, J ) + 120 CONTINUE + END IF + DO 140, K = 1, J - 1 + IF( UPPER )THEN + TEMP1 = ALPHA*A( K, J ) + ELSE + TEMP1 = ALPHA*DCONJG( A( J, K ) ) + END IF + DO 130, I = 1, M + C( I, J ) = C( I, J ) + TEMP1*B( I, K ) + 130 CONTINUE + 140 CONTINUE + DO 160, K = J + 1, N + IF( UPPER )THEN + TEMP1 = ALPHA*DCONJG( A( J, K ) ) + ELSE + TEMP1 = ALPHA*A( K, J ) + END IF + DO 150, I = 1, M + C( I, J ) = C( I, J ) + TEMP1*B( I, K ) + 150 CONTINUE + 160 CONTINUE + 170 CONTINUE + END IF +* + RETURN +* +* End of ZHEMM . +* + END |