Provided by: liblapack-doc_3.3.1-1_all

#### NAME

```       LAPACK-3 - computes the inverse of a real upper or lower triangular matrix

```

#### SYNOPSIS

```       SUBROUTINE STRTI2( UPLO, DIAG, N, A, LDA, INFO )

CHARACTER      DIAG, UPLO

INTEGER        INFO, LDA, N

REAL           A( LDA, * )

```

#### PURPOSE

```       STRTI2 computes the inverse of a real upper or lower triangular matrix.
This is the Level 2 BLAS version of the algorithm.

```

#### ARGUMENTS

```        UPLO    (input) CHARACTER*1
Specifies whether the matrix A is upper or lower triangular.
= 'U':  Upper triangular
= 'L':  Lower triangular

DIAG    (input) CHARACTER*1
Specifies whether or not the matrix A is unit triangular.
= 'N':  Non-unit triangular
= 'U':  Unit triangular

N       (input) INTEGER
The order of the matrix A.  N >= 0.

A       (input/output) REAL array, dimension (LDA,N)
On entry, the triangular matrix A.  If UPLO = 'U', the
leading n by n upper triangular part of the array A contains
the upper triangular matrix, and the strictly lower
triangular part of A is not referenced.  If UPLO = 'L', the
leading n by n lower triangular part of the array A contains
the lower triangular matrix, and the strictly upper
triangular part of A is not referenced.  If DIAG = 'U', the
diagonal elements of A are also not referenced and are
assumed to be 1.
On exit, the (triangular) inverse of the original matrix, in
the same storage format.

LDA     (input) INTEGER
The leading dimension of the array A.  LDA >= max(1,N).

INFO    (output) INTEGER
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value

LAPACK routine (version 3.2)               April 2011                            STRTI2(3lapack)
```