NAME

ctrti2 - compute the inverse of a complex upper or lower triangular matrix

SYNOPSIS

  SUBROUTINE CTRTI2( UPLO, DIAG, N, A, LDA, INFO)
  CHARACTER * 1 UPLO, DIAG
  COMPLEX A(LDA,*)
  INTEGER N, LDA, INFO

  SUBROUTINE CTRTI2_64( UPLO, DIAG, N, A, LDA, INFO)
  CHARACTER * 1 UPLO, DIAG
  COMPLEX A(LDA,*)
  INTEGER*8 N, LDA, INFO

F95 INTERFACE

  SUBROUTINE TRTI2( UPLO, DIAG, [N], A, [LDA], [INFO])
  CHARACTER(LEN=1) :: UPLO, DIAG
  COMPLEX, DIMENSION(:,:) :: A
  INTEGER :: N, LDA, INFO

  SUBROUTINE TRTI2_64( UPLO, DIAG, [N], A, [LDA], [INFO])
  CHARACTER(LEN=1) :: UPLO, DIAG
  COMPLEX, DIMENSION(:,:) :: A
  INTEGER(8) :: N, LDA, INFO

C INTERFACE

#include <sunperf.h>

void ctrti2(char uplo, char diag, int n, complex *a, int lda, int *info);

void ctrti2_64(char uplo, char diag, long n, complex *a, long lda, long *info);

PURPOSE

ctrti2 computes the inverse of a complex upper or lower triangular matrix.

This is the Level 2 BLAS version of the algorithm.

ARGUMENTS

UPLO (input)
Specifies whether the matrix A is upper or lower triangular. = 'U': Upper triangular
```
 = 'L':  Lower triangular
```
DIAG (input)
Specifies whether or not the matrix A is unit triangular. = 'N': Non-unit triangular
```
 = 'U':  Unit triangular
```
N (input)
The order of the matrix A. N > = 0.
A (input/output)
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)
The leading dimension of the array A. LDA > = max(1,N).

INFO (output)

 = 0: successful exit

 < 0: if INFO  = -k, the k-th argument had an illegal value