DTRTTP copies a triangular matrix A from full format (TR) to standard


 packed format (TP).

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 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

          LDA is INTEGER


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

AP

          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

          INFO is INTEGER


          = 0:  successful exit


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

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NAG Ltd.

June 2017