chifa

NAME

chifa - (obsolete) compute the UDU factorization of a Hermitian matrix A. It is typical to follow a call to CHIFA with a call to CHISL to solve Ax = b or to CHIDI to compute the determinant, inverse, and inertia of A.

SYNOPSIS

  SUBROUTINE CHIFA( A, LDA, N, IPIVOT, INFO)
  COMPLEX A(LDA,*)
  INTEGER LDA, N, INFO
  INTEGER IPIVOT(*)
 
  SUBROUTINE CHIFA_64( A, LDA, N, IPIVOT, INFO)
  COMPLEX A(LDA,*)
  INTEGER*8 LDA, N, INFO
  INTEGER*8 IPIVOT(*)

C INTERFACE

#include <sunperf.h>

void chifa(complex *a, int lda, int n, int *ipivot, int *info);

void chifa_64(complex *a, long lda, long n, long *ipivot, long *info);

ARGUMENTS

* A (input/output)

On entry, the upper triangle of the matrix A. On exit, a UDU factorization of the matrix A. 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.

* IPIVOT (output)

On exit, a vector of pivot indices.

* INFO (output)

On exit:

INFO = 0 Subroutine completed normally.

INFO > 0 Returns a value k if the kth pivot block is singular to indicate that CHISL or CHIDI will divide by zero if called.