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MAN page from openSUSE Leap 42 blas-man-3.5.0-9.1.noarch.rpm
chpr.fSection: LAPACK (3) Updated: Fri Nov 4 2016 Index NAMEchpr.f - SYNOPSIS Functions/Subroutines
subroutine CHPR (UPLO, N, ALPHA, X, INCX, AP)
CHPR
Function/Subroutine Documentation subroutine CHPR (character UPLO, integer N, real ALPHA, complex, dimension(*) X, integer INCX, 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 132 of file chpr.f. 132 *133 * -- Reference BLAS level2 routine (version 3.4.0) --134 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --135 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--136 * November 2011137 *138 * .. Scalar Arguments ..139 REAL alpha140 INTEGER incx,n141 CHARACTER uplo142 * ..143 * .. Array Arguments ..144 COMPLEX ap(*),x(*)145 * ..146 *147 * =====================================================================148 *149 * .. Parameters ..150 COMPLEX zero151 parameter(zero= (0.0e+0,0.0e+0))152 * ..153 * .. Local Scalars ..154 COMPLEX temp155 INTEGER i,info,ix,j,jx,k,kk,kx156 * ..157 * .. External Functions ..158 LOGICAL lsame159 EXTERNAL lsame160 * ..161 * .. External Subroutines ..162 EXTERNAL xerbla163 * ..164 * .. Intrinsic Functions ..165 INTRINSIC conjg,real166 * ..167 *168 * Test the input parameters.169 *170 info = 0171 IF (.NOT.lsame(uplo,'U') .AND. .NOT.lsame(uplo,'L')) THEN172 info = 1173 ELSE IF (n.LT.0) THEN174 info = 2175 ELSE IF (incx.EQ.0) THEN176 info = 5177 END IF178 IF (info.NE.0) THEN179 CALL xerbla('CHPR ',info)180 RETURN181 END IF182 *183 * Quick return if possible.184 *185 IF ((n.EQ.0) .OR. (alpha.EQ.REAL(zero))) return186 *187 * Set the start point in X if the increment is not unity.188 *189 IF (incx.LE.0) THEN190 kx = 1 - (n-1)*incx191 ELSE IF (incx.NE.1) THEN192 kx = 1193 END IF194 *195 * Start the operations. In this version the elements of the array AP196 * are accessed sequentially with one pass through AP.197 *198 kk = 1199 IF (lsame(uplo,'U')) THEN200 *201 * Form A when upper triangle is stored in AP.202 *203 IF (incx.EQ.1) THEN204 DO 20 j = 1,n205 IF (x(j).NE.zero) THEN206 temp = alpha*conjg(x(j))207 k = kk208 DO 10 i = 1,j - 1209 ap(k) = ap(k) + x(i)*temp210 k = k + 1211 10 CONTINUE212 ap(kk+j-1) = REAL(AP(KK+J-1)) + REAL(x(j)*temp)213 ELSE214 ap(kk+j-1) = REAL(ap(kk+j-1))215 END IF216 kk = kk + j217 20 CONTINUE218 ELSE219 jx = kx220 DO 40 j = 1,n221 IF (x(jx).NE.zero) THEN222 temp = alpha*conjg(x(jx))223 ix = kx224 DO 30 k = kk,kk + j - 2225 ap(k) = ap(k) + x(ix)*temp226 ix = ix + incx227 30 CONTINUE228 ap(kk+j-1) = REAL(AP(KK+J-1)) + REAL(x(jx)*temp)229 ELSE230 ap(kk+j-1) = REAL(ap(kk+j-1))231 END IF232 jx = jx + incx233 kk = kk + j234 40 CONTINUE235 END IF236 ELSE237 *238 * Form A when lower triangle is stored in AP.239 *240 IF (incx.EQ.1) THEN241 DO 60 j = 1,n242 IF (x(j).NE.zero) THEN243 temp = alpha*conjg(x(j))244 ap(kk) = REAL(AP(KK)) + REAL(temp*x(j))245 k = kk + 1246 DO 50 i = j + 1,n247 ap(k) = ap(k) + x(i)*temp248 k = k + 1249 50 CONTINUE250 ELSE251 ap(kk) = REAL(ap(kk))252 END IF253 kk = kk + n - j + 1254 60 CONTINUE255 ELSE256 jx = kx257 DO 80 j = 1,n258 IF (x(jx).NE.zero) THEN259 temp = alpha*conjg(x(jx))260 ap(kk) = REAL(AP(KK)) + REAL(temp*x(jx))261 ix = jx262 DO 70 k = kk + 1,kk + n - j263 ix = ix + incx264 ap(k) = ap(k) + x(ix)*temp265 70 CONTINUE266 ELSE267 ap(kk) = REAL(ap(kk))268 END IF269 jx = jx + incx270 kk = kk + n - j + 1271 80 CONTINUE272 END IF273 END IF274 *275 RETURN276 *277 * End of CHPR .278 * AuthorGenerated automatically by Doxygen for LAPACK from the source code.
Index- NAME
- SYNOPSIS
- Functions/Subroutines
- Function/Subroutine Documentation
- subroutine CHPR (character UPLO, integer N, real ALPHA, complex, dimension(*) X, integer INCX, complex, dimension(*) AP)
- Author
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