gemv - gemv: general matrix-vector multiply

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subroutinecgemv(charactertrans,integerm,integern,complexalpha,complex,dimension(lda,*)a,integerlda,complex,dimension(*)x,integerincx,complexbeta,complex,dimension(*)y,integerincy)CGEMVPurpose: CGEMV performs one of the matrix-vector operations y := alpha*A*x + beta*y, or y := alpha*A**T*x + beta*y, or y := alpha*A**H*x + beta*y, where alpha and beta are scalars, x and y are vectors and A is an m by n matrix. ParametersTRANS TRANS is CHARACTER*1 On entry, TRANS specifies the operation to be performed as follows: TRANS = 'N' or 'n' y := alpha*A*x + beta*y. TRANS = 'T' or 't' y := alpha*A**T*x + beta*y. TRANS = 'C' or 'c' y := alpha*A**H*x + beta*y. M M is INTEGER On entry, M specifies the number of rows of the matrix A. M must be at least zero. N N is INTEGER On entry, N specifies the number of columns of the matrix A. N must be at least zero. ALPHA ALPHA is COMPLEX On entry, ALPHA specifies the scalar alpha. A A is COMPLEX array, dimension ( LDA, N ) Before entry, the leading m by n part of the array A must contain the matrix of coefficients. LDA LDA is INTEGER On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, m ). X X is COMPLEX array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry, the incremented array X must contain the vector x. INCX INCX is INTEGER On entry, INCX specifies the increment for the elements of X. INCX must not be zero. BETA BETA is COMPLEX On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input. Y Y is COMPLEX array, dimension at least ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry with BETA non-zero, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y. If either m or n is zero, then Y not referenced and the function performs a quick return. INCY INCY is INTEGER On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. FurtherDetails: Level 2 Blas routine. The vector and matrix arguments are not referenced when N = 0, or M = 0 -- 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. subroutinedgemv(charactertrans,integerm,integern,doubleprecisionalpha,doubleprecision,dimension(lda,*)a,integerlda,doubleprecision,dimension(*)x,integerincx,doubleprecisionbeta,doubleprecision,dimension(*)y,integerincy)DGEMVPurpose: DGEMV performs one of the matrix-vector operations y := alpha*A*x + beta*y, or y := alpha*A**T*x + beta*y, where alpha and beta are scalars, x and y are vectors and A is an m by n matrix. ParametersTRANS TRANS is CHARACTER*1 On entry, TRANS specifies the operation to be performed as follows: TRANS = 'N' or 'n' y := alpha*A*x + beta*y. TRANS = 'T' or 't' y := alpha*A**T*x + beta*y. TRANS = 'C' or 'c' y := alpha*A**T*x + beta*y. M M is INTEGER On entry, M specifies the number of rows of the matrix A. M must be at least zero. N N is INTEGER On entry, N specifies the number of columns of the matrix A. N must be at least zero. ALPHA ALPHA is DOUBLE PRECISION. On entry, ALPHA specifies the scalar alpha. A A is DOUBLE PRECISION array, dimension ( LDA, N ) Before entry, the leading m by n part of the array A must contain the matrix of coefficients. LDA LDA is INTEGER On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, m ). X X is DOUBLE PRECISION array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry, the incremented array X must contain the vector x. INCX INCX is INTEGER On entry, INCX specifies the increment for the elements of X. INCX must not be zero. BETA BETA is DOUBLE PRECISION. On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input. Y Y is DOUBLE PRECISION array, dimension at least ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry with BETA non-zero, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y. If either m or n is zero, then Y not referenced and the function performs a quick return. INCY INCY is INTEGER On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. FurtherDetails: Level 2 Blas routine. The vector and matrix arguments are not referenced when N = 0, or M = 0 -- 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. subroutinesgemv(charactertrans,integerm,integern,realalpha,real,dimension(lda,*)a,integerlda,real,dimension(*)x,integerincx,realbeta,real,dimension(*)y,integerincy)SGEMVPurpose: SGEMV performs one of the matrix-vector operations y := alpha*A*x + beta*y, or y := alpha*A**T*x + beta*y, where alpha and beta are scalars, x and y are vectors and A is an m by n matrix. ParametersTRANS TRANS is CHARACTER*1 On entry, TRANS specifies the operation to be performed as follows: TRANS = 'N' or 'n' y := alpha*A*x + beta*y. TRANS = 'T' or 't' y := alpha*A**T*x + beta*y. TRANS = 'C' or 'c' y := alpha*A**T*x + beta*y. M M is INTEGER On entry, M specifies the number of rows of the matrix A. M must be at least zero. N N is INTEGER On entry, N specifies the number of columns of the matrix A. N must be at least zero. ALPHA ALPHA is REAL On entry, ALPHA specifies the scalar alpha. A A is REAL array, dimension ( LDA, N ) Before entry, the leading m by n part of the array A must contain the matrix of coefficients. LDA LDA is INTEGER On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, m ). X X is REAL array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry, the incremented array X must contain the vector x. INCX INCX is INTEGER On entry, INCX specifies the increment for the elements of X. INCX must not be zero. BETA BETA is REAL On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input. Y Y is REAL array, dimension at least ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry with BETA non-zero, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y. If either m or n is zero, then Y not referenced and the function performs a quick return. INCY INCY is INTEGER On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. FurtherDetails: Level 2 Blas routine. The vector and matrix arguments are not referenced when N = 0, or M = 0 -- 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. subroutinezgemv(charactertrans,integerm,integern,complex*16alpha,complex*16,dimension(lda,*)a,integerlda,complex*16,dimension(*)x,integerincx,complex*16beta,complex*16,dimension(*)y,integerincy)ZGEMVPurpose: ZGEMV performs one of the matrix-vector operations y := alpha*A*x + beta*y, or y := alpha*A**T*x + beta*y, or y := alpha*A**H*x + beta*y, where alpha and beta are scalars, x and y are vectors and A is an m by n matrix. ParametersTRANS TRANS is CHARACTER*1 On entry, TRANS specifies the operation to be performed as follows: TRANS = 'N' or 'n' y := alpha*A*x + beta*y. TRANS = 'T' or 't' y := alpha*A**T*x + beta*y. TRANS = 'C' or 'c' y := alpha*A**H*x + beta*y. M M is INTEGER On entry, M specifies the number of rows of the matrix A. M must be at least zero. N N is INTEGER On entry, N specifies the number of columns of the matrix A. N must be at least zero. ALPHA ALPHA is COMPLEX*16 On entry, ALPHA specifies the scalar alpha. A A is COMPLEX*16 array, dimension ( LDA, N ) Before entry, the leading m by n part of the array A must contain the matrix of coefficients. LDA LDA is INTEGER On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA must be at least max( 1, m ). X X is COMPLEX*16 array, dimension at least ( 1 + ( n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( m - 1 )*abs( INCX ) ) otherwise. Before entry, the incremented array X must contain the vector x. INCX INCX is INTEGER On entry, INCX specifies the increment for the elements of X. INCX must not be zero. BETA BETA is COMPLEX*16 On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input. Y Y is COMPLEX*16 array, dimension at least ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N' or 'n' and at least ( 1 + ( n - 1 )*abs( INCY ) ) otherwise. Before entry with BETA non-zero, the incremented array Y must contain the vector y. On exit, Y is overwritten by the updated vector y. If either m or n is zero, then Y not referenced and the function performs a quick return. INCY INCY is INTEGER On entry, INCY specifies the increment for the elements of Y. INCY must not be zero. Author Univ. of Tennessee Univ. of California Berkeley Univ. of Colorado Denver NAG Ltd. FurtherDetails: Level 2 Blas routine. The vector and matrix arguments are not referenced when N = 0, or M = 0 -- 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.

gemv - gemv: general matrix-vector multiply

Functions subroutine cgemv (trans, m, n, alpha, a, lda, x, incx, beta, y, incy) CGEMV subroutine dgemv (trans, m, n, alpha, a, lda, x, incx, beta, y, incy) DGEMV subroutine sgemv (trans, m, n, alpha, a, lda, x, incx, beta, y, incy) SGEMV subroutine zgemv (trans, m, n, alpha, a, lda, x, incx, beta, y, incy) ZGEMV