DTRTTP(3)      LAPACK routine of NEC Numeric Library Collection      DTRTTP(3)



NAME
       DTRTTP

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



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




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

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

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

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



LAPACK routine                  31 October 2017                      DTRTTP(3)