# ctrttp.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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ctrttp.f

## SYNOPSIS

### Functions/Subroutines

subroutine ctrttp (UPLO, N, A, LDA, AP, INFO)
CTRTTP copies a triangular matrix from the standard full format (TR) to the standard packed format (TP).

## Function/Subroutine Documentation

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

CTRTTP copies a triangular matrix from the standard full format (TR) to the standard packed format (TP).

Purpose:

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

Parameters:

UPLO

```          UPLO is CHARACTER*1
= 'U':  A is upper triangular;
= 'L':  A is lower triangular.
```

N

```          N is INTEGER
The order of the matrices AP and 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 A contains the upper
triangular part of the matrix A, and the strictly lower
triangular part of A is not referenced.  If UPLO = 'L', 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

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

AP

```          AP is COMPLEX array, dimension ( N*(N+1)/2 ),
On exit, 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 = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
```

INFO

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

Author:

Univ. of Tennessee

Univ. of California Berkeley