# ctpttr (l) - Linux Manuals

## NAME

CTPTTR - copies a triangular matrix A from standard packed format (TP) to standard full format (TR)

## SYNOPSIS

SUBROUTINE CTPTTR(
UPLO, N, AP, A, LDA, INFO )

CHARACTER UPLO

INTEGER INFO, N, LDA

COMPLEX A( LDA, * ), AP( * )

## PURPOSE

CTPTTR copies a triangular matrix A from standard packed format (TP) to standard full format (TR).

## ARGUMENTS

UPLO (input) CHARACTER
= aqUaq: A is upper triangular.
= aqLaq: A is lower triangular.
N (input) INTEGER
The order of the matrix A. N >= 0.
AP (input) COMPLEX array, dimension ( N*(N+1)/2 ),
On entry, the upper or lower triangular matrix A, packed columnwise in a linear array. The j-th column of A is stored in the array AP as follows: if UPLO = aqUaq, AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = aqLaq, AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
A (output) COMPLEX array, dimension ( LDA, N )
On exit, the triangular matrix A. If UPLO = aqUaq, the leading N-by-N upper triangular part of A contains the upper triangular part of the matrix A, and the strictly lower triangular part of A is not referenced. If UPLO = aqLaq, the leading N-by-N lower triangular part of A contains the lower triangular part of the matrix A, and the strictly upper triangular part of A is not referenced.
LDA (input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
INFO (output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value