zchud

NAME

zchud - (obsolete) update an augmented Cholesky decomposition of the triangular part of an augmented QR decomposition.

SYNOPSIS

  SUBROUTINE ZCHUD( A, LDA, N, X, Z, LDZ, NZ, Y, RHO, COS, SIN)
  DOUBLE COMPLEX A(LDA,*), X(*), Z(LDZ,*), Y(*), SIN(*)
  INTEGER LDA, N, LDZ, NZ
  DOUBLE PRECISION RHO(*), COS(*)
 
  SUBROUTINE ZCHUD_64( A, LDA, N, X, Z, LDZ, NZ, Y, RHO, COS, SIN)
  DOUBLE COMPLEX A(LDA,*), X(*), Z(LDZ,*), Y(*), SIN(*)
  INTEGER*8 LDA, N, LDZ, NZ
  DOUBLE PRECISION RHO(*), COS(*)

C INTERFACE

#include <sunperf.h>

void zchud(doublecomplex *a, int lda, int n, doublecomplex *x, doublecomplex *z, int ldz, int nz, doublecomplex *y, double *rho, double *cos, doublecomplex *sin);

void zchud_64(doublecomplex *a, long lda, long n, doublecomplex *x, doublecomplex *z, long ldz, long nz, doublecomplex *y, double *rho, double *cos, doublecomplex *sin);

ARGUMENTS

* A (input/output): On entry, the upper triangular matrix A. On exit, A has been updated. The strict lower triangle of A is not referenced.
* LDA (input): Leading dimension of the array A as specified in a dimension or type statement. LDA >= max(1,N).
* N (input): Order of the matrix A. N >= 0.
* X (input): Row to be added to A.
* Z (input/output): Vectors to be updated with A.
* LDZ (input): Leading dimension on the array Z as specified in a dimension or type statement. LDZ >= max(1,N).
* NZ (input): Number of vectors to be updated with A. NZ >= 0. If NZ = 0 then Z, Y, and RHO are not used.
* Y (input): Scalars for updating the vectors in Z.
* RHO (input/output): On entry, the norms of the residual vectors that are to be updated. On exit, RHO has been updated. If RHO(i) is negative on entry then it is not changed.
* COS (input): Cosines of the transforming rotations.
* SIN (input): Sines of the transforming rotations.