SUBROUTINE ZGEMM ( TRANSA, TRANSB, M, N, K, ALPHA, A, LDA, B, LDB, $ BETA, C, LDC ) * .. Scalar Arguments .. CHARACTER*1 TRANSA, TRANSB INTEGER M, N, K, LDA, LDB, LDC COMPLEX*16 ALPHA, BETA * .. Array Arguments .. COMPLEX*16 A( LDA, * ), B( LDB, * ), C( LDC, * ) * .. * * Purpose * ======= * * ZGEMM 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' or op( X ) = conjg( 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. * * Parameters * ========== * * 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 ) = conjg( 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 ) = conjg( 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 - COMPLEX*16 . * On entry, ALPHA specifies the scalar alpha. * Unchanged on exit. * * A - COMPLEX*16 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 - COMPLEX*16 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 - 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 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 DCONJG, MAX * .. Local Scalars .. LOGICAL CONJA, CONJB, NOTA, NOTB INTEGER I, INFO, J, L, NCOLA, NROWA, NROWB COMPLEX*16 TEMP * .. 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 NOTA and NOTB as true if A and B respectively are not * conjugated or transposed, set CONJA and CONJB as true if A and * B respectively are to be transposed but not conjugated 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' ) CONJA = LSAME( TRANSA, 'C' ) CONJB = LSAME( TRANSB, 'C' ) 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.CONJA ).AND. $ ( .NOT.LSAME( TRANSA, 'T' ) ) )THEN INFO = 1 ELSE IF( ( .NOT.NOTB ).AND. $ ( .NOT.CONJB ).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( 'ZGEMM ', 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 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( 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 IF( CONJA )THEN * * Form C := alpha*conjg( A' )*B + beta*C. * DO 120, J = 1, N DO 110, I = 1, M TEMP = ZERO DO 100, L = 1, K TEMP = TEMP + DCONJG( 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 ELSE * * Form C := alpha*A'*B + beta*C * DO 150, J = 1, N DO 140, I = 1, M TEMP = ZERO DO 130, L = 1, K TEMP = TEMP + A( L, I )*B( L, J ) 130 CONTINUE IF( BETA.EQ.ZERO )THEN C( I, J ) = ALPHA*TEMP ELSE C( I, J ) = ALPHA*TEMP + BETA*C( I, J ) END IF 140 CONTINUE 150 CONTINUE END IF ELSE IF( NOTA )THEN IF( CONJB )THEN * * Form C := alpha*A*conjg( B' ) + beta*C. * DO 200, J = 1, N IF( BETA.EQ.ZERO )THEN DO 160, I = 1, M C( I, J ) = ZERO 160 CONTINUE ELSE IF( BETA.NE.ONE )THEN DO 170, I = 1, M C( I, J ) = BETA*C( I, J ) 170 CONTINUE END IF DO 190, L = 1, K IF( B( J, L ).NE.ZERO )THEN TEMP = ALPHA*DCONJG( B( J, L ) ) DO 180, I = 1, M C( I, J ) = C( I, J ) + TEMP*A( I, L ) 180 CONTINUE END IF 190 CONTINUE 200 CONTINUE ELSE * * Form C := alpha*A*B' + beta*C * DO 250, J = 1, N IF( BETA.EQ.ZERO )THEN DO 210, I = 1, M C( I, J ) = ZERO 210 CONTINUE ELSE IF( BETA.NE.ONE )THEN DO 220, I = 1, M C( I, J ) = BETA*C( I, J ) 220 CONTINUE END IF DO 240, L = 1, K IF( B( J, L ).NE.ZERO )THEN TEMP = ALPHA*B( J, L ) DO 230, I = 1, M C( I, J ) = C( I, J ) + TEMP*A( I, L ) 230 CONTINUE END IF 240 CONTINUE 250 CONTINUE END IF ELSE IF( CONJA )THEN IF( CONJB )THEN * * Form C := alpha*conjg( A' )*conjg( B' ) + beta*C. * DO 280, J = 1, N DO 270, I = 1, M TEMP = ZERO DO 260, L = 1, K TEMP = TEMP + $ DCONJG( A( L, I ) )*DCONJG( B( J, L ) ) 260 CONTINUE IF( BETA.EQ.ZERO )THEN C( I, J ) = ALPHA*TEMP ELSE C( I, J ) = ALPHA*TEMP + BETA*C( I, J ) END IF 270 CONTINUE 280 CONTINUE ELSE * * Form C := alpha*conjg( A' )*B' + beta*C * DO 310, J = 1, N DO 300, I = 1, M TEMP = ZERO DO 290, L = 1, K TEMP = TEMP + DCONJG( A( L, I ) )*B( J, L ) 290 CONTINUE IF( BETA.EQ.ZERO )THEN C( I, J ) = ALPHA*TEMP ELSE C( I, J ) = ALPHA*TEMP + BETA*C( I, J ) END IF 300 CONTINUE 310 CONTINUE END IF ELSE IF( CONJB )THEN * * Form C := alpha*A'*conjg( B' ) + beta*C * DO 340, J = 1, N DO 330, I = 1, M TEMP = ZERO DO 320, L = 1, K TEMP = TEMP + A( L, I )*DCONJG( B( J, L ) ) 320 CONTINUE IF( BETA.EQ.ZERO )THEN C( I, J ) = ALPHA*TEMP ELSE C( I, J ) = ALPHA*TEMP + BETA*C( I, J ) END IF 330 CONTINUE 340 CONTINUE ELSE * * Form C := alpha*A'*B' + beta*C * DO 370, J = 1, N DO 360, I = 1, M TEMP = ZERO DO 350, L = 1, K TEMP = TEMP + A( L, I )*B( J, L ) 350 CONTINUE IF( BETA.EQ.ZERO )THEN C( I, J ) = ALPHA*TEMP ELSE C( I, J ) = ALPHA*TEMP + BETA*C( I, J ) END IF 360 CONTINUE 370 CONTINUE END IF END IF * RETURN * * End of ZGEMM . * END