chpr.f man page

chpr.f —

Synopsis

Functions/Subroutines

subroutine chpr (UPLO, N, ALPHA, X, INCX, AP)
CHPR

Function/Subroutine Documentation

subroutine chpr (characterUPLO, integerN, realALPHA, complex, dimension(*)X, integerINCX, complex, dimension(*)AP)

CHPR Purpose:

CHPR    performs the hermitian rank 1 operation

   A := alpha*x*x**H + A,

where alpha is a real scalar, x is an n element vector and A is an
n by n hermitian matrix, supplied in packed form.

Parameters:

UPLO

UPLO is CHARACTER*1
 On entry, UPLO specifies whether the upper or lower
 triangular part of the matrix A is supplied in the packed
 array AP as follows:

    UPLO = 'U' or 'u'   The upper triangular part of A is
                        supplied in AP.

    UPLO = 'L' or 'l'   The lower triangular part of A is
                        supplied in AP.

N

N is INTEGER
 On entry, N specifies the order of the matrix A.
 N must be at least zero.

ALPHA

ALPHA is REAL
 On entry, ALPHA specifies the scalar alpha.

X

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

INCX

INCX is INTEGER
 On entry, INCX specifies the increment for the elements of
 X. INCX must not be zero.

AP

AP is COMPLEX array of DIMENSION at least
 ( ( n*( n + 1 ) )/2 ).
 Before entry with  UPLO = 'U' or 'u', the array AP must
 contain the upper triangular part of the hermitian matrix
 packed sequentially, column by column, so that AP( 1 )
 contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 )
 and a( 2, 2 ) respectively, and so on. On exit, the array
 AP is overwritten by the upper triangular part of the
 updated matrix.
 Before entry with UPLO = 'L' or 'l', the array AP must
 contain the lower triangular part of the hermitian matrix
 packed sequentially, column by column, so that AP( 1 )
 contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 )
 and a( 3, 1 ) respectively, and so on. On exit, the array
 AP is overwritten by the lower triangular part of the
 updated matrix.
 Note that the imaginary parts of the diagonal elements need
 not be set, they are assumed to be zero, and on exit they
 are set to zero.

Author:

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date:

November 2011

Further Details:

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.

Definition at line 131 of file chpr.f.

Author

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Referenced By

chpr(3) is an alias of chpr.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK