by-M part of this array must
          contain the matrix B.
          On exit, the leading P-by-M part of this array contains
          the computed matrix D.

  LDB     INTEGER
          The leading dimension of array B.  LDB &gt;= MAX(1,P).

  C       (output) DOUBLE PRECISION array, dimension (LDC,M)
          The leading N-by-M part of this array contains the
          computed matrix C.

  LDC     INTEGER
          The leading dimension of array C.  LDC &gt;= MAX(1,N).

  TAU     (output) DOUBLE PRECI