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

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

          N is INTEGER
          The order of the matrix A. N >= 0.

          AP is DOUBLE PRECISION 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 = '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.

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

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