# cpptri.f man page

cpptri.f

## Synopsis

### Functions/Subroutines

subroutine cpptri (UPLO, N, AP, INFO)
CPPTRI

## Function/Subroutine Documentation

### subroutine cpptri (character UPLO, integer N, complex, dimension( * ) AP, integer INFO)

CPPTRI

Purpose:

``` CPPTRI computes the inverse of a complex Hermitian positive definite
matrix A using the Cholesky factorization A = U**H*U or A = L*L**H
computed by CPPTRF.```
Parameters:

UPLO

```          UPLO is CHARACTER*1
= 'U':  Upper triangular factor is stored in AP;
= 'L':  Lower triangular factor is stored in AP.```

N

```          N is INTEGER
The order of the matrix A.  N >= 0.```

AP

```          AP is COMPLEX array, dimension (N*(N+1)/2)
On entry, the triangular factor U or L from the Cholesky
factorization A = U**H*U or A = L*L**H, packed columnwise as
a linear array.  The j-th column of U or L is stored in the
array AP as follows:
if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n.

On exit, the upper or lower triangle of the (Hermitian)
inverse of A, overwriting the input factor U or L.```

INFO

```          INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value
> 0:  if INFO = i, the (i,i) element of the factor U or L is
zero, and the inverse could not be computed.```
Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

December 2016

Definition at line 95 of file cpptri.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page cpptri(3) is an alias of cpptri.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK