ero then A and X are not
          referenced.

  R       (input/output) DOUBLE PRECISION array, dimension (LDR,M)
          On entry with UPLO = 'U', the leading M-by-M upper
          triangular part of this array must contain the upper
          triangular part of the symmetric matrix R; the strictly
          lower triangular part of the array is used as workspace.
          On entry with UPLO = 'L', the leading M-by-M lower
          triangular part of this array must contain the lower
          triang