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man pages->IRIX man pages -> complib/CHIFA (3)
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### Contents

```
CHIFA(3F)							     CHIFA(3F)

```

### NAME[Toc][Back]

```     CHIFA   - CHIFA factors a complex Hermitian matrix	by elimination with
symmetric pivoting.

To	solve  A*X = B , follow	CHIFA by CHISL.	 To compute  INVERSE(A)*C ,
CHIDI.  To	compute	 INERTIA(A) , follow CHIFA by CHIDI.  To compute
INVERSE(A)	, follow CHIFA by CHIDI.

```

### SYNOPSYS[Toc][Back]

```      SUBROUTINE CHIFA(A,LDA,N,KPVT,INFO)
```

### DESCRIPTION[Toc][Back]

```     On	Entry

A COMPLEX(LDA,N)
the Hermitian matrix to	be factored.
Only the diagonal and upper triangle are used.

LDA INTEGER
the leading dimension of the array  A .

N INTEGER
the order of the matrix	 A .  On Return

A a block diagonal	matrix and the multipliers which
were used to obtain it.
The factorization can be written  A = U*D*CTRANS(U)
where  U  is a product of permutation and unit
upper triangular matrices , CTRANS(U) is the
conjugate transpose of	U , and	 D  is block diagonal
with 1 by 1 and	2 by 2 blocks.	KVPT	INTEGER(N)
an integer vector of pivot indices.

INFO INTEGER
= 0  normal value.
= K  if	the K-th pivot block is	singular.  This	is
not an error condition for this	subroutine,
but it does indicate that CHISL	or CHIDI may
divide by zero if called.  LINPACK.  This version dated	08/14/78 .
James Bunch, Univ.	Calif. San Diego, Argonne Nat. Lab.  Subroutines and
Functions BLAS CAXPY,CSWAP,ICAMAX Fortran
ABS,AIMAG,AMAX1,CMPLX,CONJG,REAL,SQRT

PPPPaaaaggggeeee 1111```
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