dsyr(3) [debian man page]

DSYR(3) 							   BLAS routine 							   DSYR(3)

NAME

       DSYR - perform the symmetric rank 1 operation   A := alpha*x*x' + A,

SYNOPSIS

       SUBROUTINE DSYR ( UPLO, N, ALPHA, X, INCX, A, LDA )

	   DOUBLE      PRECISION ALPHA

	   INTEGER     INCX, LDA, N

	   CHARACTER*1 UPLO

	   DOUBLE      PRECISION A( LDA, * ), X( * )

PURPOSE

       DSYR   performs the symmetric rank 1 operation

       where alpha is a real scalar, x is an n element vector and A is an n by n symmetric matrix.

PARAMETERS

       UPLO   - CHARACTER*1.
	      On entry, UPLO specifies whether the upper or lower triangular part of the array A is to be referenced as follows:

	      UPLO = 'U' or 'u'   Only the upper triangular part of A is to be referenced.

	      UPLO = 'L' or 'l'   Only the lower triangular part of A is to be referenced.

	      Unchanged on exit.

       N      - INTEGER.
	      On entry, N specifies the order of the matrix A.	N must be at least zero.  Unchanged on exit.

       ALPHA  - DOUBLE PRECISION.
	      On entry, ALPHA specifies the scalar alpha.  Unchanged on exit.

       X      - DOUBLE PRECISION array of dimension at least
	      ( 1 + ( n - 1 )*abs( INCX ) ).  Before entry, the incremented array X must contain the n element 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.

       A      - DOUBLE PRECISION array of DIMENSION ( LDA, n ).
	      Before entry with  UPLO = 'U' or 'u', the leading n by n upper triangular part of the array A must contain the upper triangular part
	      of the symmetric matrix and the strictly lower triangular part of A is not referenced. On exit, the upper  triangular  part  of  the
	      array  A is overwritten by the upper triangular part of the updated matrix.  Before entry with UPLO = 'L' or 'l', the leading n by n
	      lower triangular part of the array A must contain the lower triangular part of the symmetric matrix and the strictly upper  triangu-
	      lar  part  of  A is not referenced. On exit, the lower triangular part of the array A is overwritten by the lower triangular part of
	      the updated matrix.

       LDA    - INTEGER.
	      On entry, LDA specifies the first dimension of A as declared in the calling (sub) program. LDA  must  be	at  least  max(  1,  n	).
	      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 Cen-
	      tral Office.  Richard Hanson, Sandia National Labs.

BLAS routine							  16 October 1992							   DSYR(3)

DSYMV(3)							   BLAS routine 							  DSYMV(3)

NAME

       DSYMV - perform the matrix-vector operation   y := alpha*A*x + beta*y,

SYNOPSIS

       SUBROUTINE DSYMV ( UPLO, N, ALPHA, A, LDA, X, INCX, BETA, Y, INCY )

	   DOUBLE	PRECISION ALPHA, BETA

	   INTEGER	INCX, INCY, LDA, N

	   CHARACTER*1	UPLO

	   DOUBLE	PRECISION A( LDA, * ), X( * ), Y( * )

PURPOSE

       DSYMV  performs the matrix-vector  operation

       where alpha and beta are scalars, x and y are n element vectors and A is an n by n symmetric matrix.

PARAMETERS

       UPLO   - CHARACTER*1.
	      On entry, UPLO specifies whether the upper or lower triangular part of the array A is to be referenced as follows:

	      UPLO = 'U' or 'u'   Only the upper triangular part of A is to be referenced.

	      UPLO = 'L' or 'l'   Only the lower triangular part of A is to be referenced.

	      Unchanged on exit.

       N      - INTEGER.
	      On entry, N specifies the order of the matrix A.	N 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, n ).
	      Before entry with  UPLO = 'U' or 'u', the leading n by n upper triangular part of the array A must contain the upper triangular part
	      of the symmetric matrix and the strictly lower triangular part of A is not referenced.  Before entry with UPLO =	'L'  or  'l',  the
	      leading  n by n lower triangular part of the array A must contain the lower triangular part of the symmetric matrix and the strictly
	      upper triangular part of A is not referenced.  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  max(  1,  n	).
	      Unchanged on exit.

       X      - DOUBLE PRECISION array of dimension at least
	      ( 1 + ( n - 1 )*abs( INCX ) ).  Before entry, the incremented array X must contain the n element 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   - DOUBLE PRECISION.
	      On entry, BETA specifies the scalar beta. When BETA is supplied as zero then Y need not be set on input.	Unchanged on exit.

       Y      - DOUBLE PRECISION array of dimension at least
	      ( 1 + ( n - 1 )*abs( INCY ) ).  Before entry, the incremented array Y must contain the n element 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 Cen-
	      tral Office.  Richard Hanson, Sandia National Labs.

BLAS routine							  16 October 1992							  DSYMV(3)