Provided by: liblapack-doc_3.3.1-1_all #### NAME

```       LAPACK-3  -  copies  a triangular matrix A from full format (TR) to standard packed format
(TP)

```

#### SYNOPSIS

```       SUBROUTINE DTRTTP( UPLO, N, A, LDA, AP, INFO )

CHARACTER      UPLO

INTEGER        INFO, N, LDA

DOUBLE         PRECISION A( LDA, * ), AP( * )

```

#### PURPOSE

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

```

#### ARGUMENTS

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

N       (input) INTEGER
The order of the matrices AP and A.  N >= 0.

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

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

LAPACK routine (version 3.3.0)             April 2011                            DTRTTP(3lapack)
```