# ctrti2.f - Man Page

## Synopsis

### Functions/Subroutines

subroutine **ctrti2** (UPLO, DIAG, **N**, A, **LDA**, INFO)**CTRTI2** computes the inverse of a triangular matrix (unblocked algorithm).

## Function/Subroutine Documentation

### subroutine ctrti2 (character UPLO, character DIAG, integer N, complex, dimension( lda, * ) A, integer LDA, integer INFO)

**CTRTI2** computes the inverse of a triangular matrix (unblocked algorithm).

**Purpose:**

CTRTI2 computes the inverse of a complex upper or lower triangular matrix. This is the Level 2 BLAS version of the algorithm.

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

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

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

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

*INFO*INFO is INTEGER = 0: successful exit < 0: if INFO = -k, the k-th argument had an illegal value

**Author:**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**December 2016

Definition at line 112 of file ctrti2.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page ctrti2(3) is an alias of ctrti2.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK