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Diffstat (limited to '2.3-1/src/fortran/blas/zhbmv.f')
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1 files changed, 309 insertions, 0 deletions
diff --git a/2.3-1/src/fortran/blas/zhbmv.f b/2.3-1/src/fortran/blas/zhbmv.f new file mode 100644 index 00000000..1c044936 --- /dev/null +++ b/2.3-1/src/fortran/blas/zhbmv.f @@ -0,0 +1,309 @@ + SUBROUTINE ZHBMV ( UPLO, N, K, ALPHA, A, LDA, X, INCX, + $ BETA, Y, INCY ) +* .. Scalar Arguments .. + COMPLEX*16 ALPHA, BETA + INTEGER INCX, INCY, K, LDA, N + CHARACTER*1 UPLO +* .. Array Arguments .. + COMPLEX*16 A( LDA, * ), X( * ), Y( * ) +* .. +* +* Purpose +* ======= +* +* ZHBMV performs the matrix-vector operation +* +* y := alpha*A*x + beta*y, +* +* where alpha and beta are scalars, x and y are n element vectors and +* A is an n by n hermitian band matrix, with k super-diagonals. +* +* Parameters +* ========== +* +* UPLO - CHARACTER*1. +* On entry, UPLO specifies whether the upper or lower +* triangular part of the band matrix A is being supplied as +* follows: +* +* UPLO = 'U' or 'u' The upper triangular part of A is +* being supplied. +* +* UPLO = 'L' or 'l' The lower triangular part of A is +* being supplied. +* +* Unchanged on exit. +* +* N - INTEGER. +* On entry, N specifies the order of the matrix A. +* N must be at least zero. +* Unchanged on exit. +* +* K - INTEGER. +* On entry, K specifies the number of super-diagonals of the +* matrix A. K must satisfy 0 .le. K. +* Unchanged on exit. +* +* ALPHA - COMPLEX*16 . +* On entry, ALPHA specifies the scalar alpha. +* Unchanged on exit. +* +* A - COMPLEX*16 array of DIMENSION ( LDA, n ). +* Before entry with UPLO = 'U' or 'u', the leading ( k + 1 ) +* by n part of the array A must contain the upper triangular +* band part of the hermitian matrix, supplied column by +* column, with the leading diagonal of the matrix in row +* ( k + 1 ) of the array, the first super-diagonal starting at +* position 2 in row k, and so on. The top left k by k triangle +* of the array A is not referenced. +* The following program segment will transfer the upper +* triangular part of a hermitian band matrix from conventional +* full matrix storage to band storage: +* +* DO 20, J = 1, N +* M = K + 1 - J +* DO 10, I = MAX( 1, J - K ), J +* A( M + I, J ) = matrix( I, J ) +* 10 CONTINUE +* 20 CONTINUE +* +* Before entry with UPLO = 'L' or 'l', the leading ( k + 1 ) +* by n part of the array A must contain the lower triangular +* band part of the hermitian matrix, supplied column by +* column, with the leading diagonal of the matrix in row 1 of +* the array, the first sub-diagonal starting at position 1 in +* row 2, and so on. The bottom right k by k triangle of the +* array A is not referenced. +* The following program segment will transfer the lower +* triangular part of a hermitian band matrix from conventional +* full matrix storage to band storage: +* +* DO 20, J = 1, N +* M = 1 - J +* DO 10, I = J, MIN( N, J + K ) +* A( M + I, J ) = matrix( I, J ) +* 10 CONTINUE +* 20 CONTINUE +* +* Note that the imaginary parts of the diagonal elements need +* not be set and 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. LDA must be at least +* ( k + 1 ). +* Unchanged on exit. +* +* X - COMPLEX*16 array of DIMENSION at least +* ( 1 + ( n - 1 )*abs( INCX ) ). +* Before entry, the incremented array X must contain the +* vector x. +* Unchanged on exit. +* +* INCX - INTEGER. +* On entry, INCX specifies the increment for the elements of +* X. INCX must not be zero. +* Unchanged on exit. +* +* BETA - COMPLEX*16 . +* On entry, BETA specifies the scalar beta. +* Unchanged on exit. +* +* Y - COMPLEX*16 array of DIMENSION at least +* ( 1 + ( n - 1 )*abs( INCY ) ). +* Before entry, the incremented array Y must contain the +* vector y. On exit, Y is overwritten by the updated vector y. +* +* INCY - INTEGER. +* On entry, INCY specifies the increment for the elements of +* Y. INCY must not be zero. +* Unchanged on exit. +* +* +* Level 2 Blas routine. +* +* -- Written on 22-October-1986. +* Jack Dongarra, Argonne National Lab. +* Jeremy Du Croz, Nag Central Office. +* Sven Hammarling, Nag Central Office. +* Richard Hanson, Sandia National Labs. +* +* +* .. Parameters .. + COMPLEX*16 ONE + PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ) ) + COMPLEX*16 ZERO + PARAMETER ( ZERO = ( 0.0D+0, 0.0D+0 ) ) +* .. Local Scalars .. + COMPLEX*16 TEMP1, TEMP2 + INTEGER I, INFO, IX, IY, J, JX, JY, KPLUS1, KX, KY, L +* .. External Functions .. + LOGICAL LSAME + EXTERNAL LSAME +* .. External Subroutines .. + EXTERNAL XERBLA +* .. Intrinsic Functions .. + INTRINSIC DCONJG, MAX, MIN, DBLE +* .. +* .. Executable Statements .. +* +* Test the input parameters. +* + INFO = 0 + IF ( .NOT.LSAME( UPLO, 'U' ).AND. + $ .NOT.LSAME( UPLO, 'L' ) )THEN + INFO = 1 + ELSE IF( N.LT.0 )THEN + INFO = 2 + ELSE IF( K.LT.0 )THEN + INFO = 3 + ELSE IF( LDA.LT.( K + 1 ) )THEN + INFO = 6 + ELSE IF( INCX.EQ.0 )THEN + INFO = 8 + ELSE IF( INCY.EQ.0 )THEN + INFO = 11 + END IF + IF( INFO.NE.0 )THEN + CALL XERBLA( 'ZHBMV ', INFO ) + RETURN + END IF +* +* Quick return if possible. +* + IF( ( N.EQ.0 ).OR.( ( ALPHA.EQ.ZERO ).AND.( BETA.EQ.ONE ) ) ) + $ RETURN +* +* Set up the start points in X and Y. +* + IF( INCX.GT.0 )THEN + KX = 1 + ELSE + KX = 1 - ( N - 1 )*INCX + END IF + IF( INCY.GT.0 )THEN + KY = 1 + ELSE + KY = 1 - ( N - 1 )*INCY + END IF +* +* Start the operations. In this version the elements of the array A +* are accessed sequentially with one pass through A. +* +* First form y := beta*y. +* + IF( BETA.NE.ONE )THEN + IF( INCY.EQ.1 )THEN + IF( BETA.EQ.ZERO )THEN + DO 10, I = 1, N + Y( I ) = ZERO + 10 CONTINUE + ELSE + DO 20, I = 1, N + Y( I ) = BETA*Y( I ) + 20 CONTINUE + END IF + ELSE + IY = KY + IF( BETA.EQ.ZERO )THEN + DO 30, I = 1, N + Y( IY ) = ZERO + IY = IY + INCY + 30 CONTINUE + ELSE + DO 40, I = 1, N + Y( IY ) = BETA*Y( IY ) + IY = IY + INCY + 40 CONTINUE + END IF + END IF + END IF + IF( ALPHA.EQ.ZERO ) + $ RETURN + IF( LSAME( UPLO, 'U' ) )THEN +* +* Form y when upper triangle of A is stored. +* + KPLUS1 = K + 1 + IF( ( INCX.EQ.1 ).AND.( INCY.EQ.1 ) )THEN + DO 60, J = 1, N + TEMP1 = ALPHA*X( J ) + TEMP2 = ZERO + L = KPLUS1 - J + DO 50, I = MAX( 1, J - K ), J - 1 + Y( I ) = Y( I ) + TEMP1*A( L + I, J ) + TEMP2 = TEMP2 + DCONJG( A( L + I, J ) )*X( I ) + 50 CONTINUE + Y( J ) = Y( J ) + TEMP1*DBLE( A( KPLUS1, J ) ) + $ + ALPHA*TEMP2 + 60 CONTINUE + ELSE + JX = KX + JY = KY + DO 80, J = 1, N + TEMP1 = ALPHA*X( JX ) + TEMP2 = ZERO + IX = KX + IY = KY + L = KPLUS1 - J + DO 70, I = MAX( 1, J - K ), J - 1 + Y( IY ) = Y( IY ) + TEMP1*A( L + I, J ) + TEMP2 = TEMP2 + DCONJG( A( L + I, J ) )*X( IX ) + IX = IX + INCX + IY = IY + INCY + 70 CONTINUE + Y( JY ) = Y( JY ) + TEMP1*DBLE( A( KPLUS1, J ) ) + $ + ALPHA*TEMP2 + JX = JX + INCX + JY = JY + INCY + IF( J.GT.K )THEN + KX = KX + INCX + KY = KY + INCY + END IF + 80 CONTINUE + END IF + ELSE +* +* Form y when lower triangle of A is stored. +* + IF( ( INCX.EQ.1 ).AND.( INCY.EQ.1 ) )THEN + DO 100, J = 1, N + TEMP1 = ALPHA*X( J ) + TEMP2 = ZERO + Y( J ) = Y( J ) + TEMP1*DBLE( A( 1, J ) ) + L = 1 - J + DO 90, I = J + 1, MIN( N, J + K ) + Y( I ) = Y( I ) + TEMP1*A( L + I, J ) + TEMP2 = TEMP2 + DCONJG( A( L + I, J ) )*X( I ) + 90 CONTINUE + Y( J ) = Y( J ) + ALPHA*TEMP2 + 100 CONTINUE + ELSE + JX = KX + JY = KY + DO 120, J = 1, N + TEMP1 = ALPHA*X( JX ) + TEMP2 = ZERO + Y( JY ) = Y( JY ) + TEMP1*DBLE( A( 1, J ) ) + L = 1 - J + IX = JX + IY = JY + DO 110, I = J + 1, MIN( N, J + K ) + IX = IX + INCX + IY = IY + INCY + Y( IY ) = Y( IY ) + TEMP1*A( L + I, J ) + TEMP2 = TEMP2 + DCONJG( A( L + I, J ) )*X( IX ) + 110 CONTINUE + Y( JY ) = Y( JY ) + ALPHA*TEMP2 + JX = JX + INCX + JY = JY + INCY + 120 CONTINUE + END IF + END IF +* + RETURN +* +* End of ZHBMV . +* + END |