DLASWP performs a series of row interchanges on the matrix A.
 One row interchange is initiated for each of rows K1 through K2 of A.

          N is INTEGER
          The number of columns of the matrix A.

          A is DOUBLE PRECISION array, dimension (LDA,N)
          On entry, the matrix of column dimension N to which the row
          interchanges will be applied.
          On exit, the permuted matrix.

          LDA is INTEGER
          The leading dimension of the array A.

          K1 is INTEGER
          The first element of IPIV for which a row interchange will
          be done.

          K2 is INTEGER
          The last element of IPIV for which a row interchange will
          be done.

          IPIV is INTEGER array, dimension (K2*abs(INCX))
          The vector of pivot indices.  Only the elements in positions
          K1 through K2 of IPIV are accessed.
          IPIV(K) = L implies rows K and L are to be interchanged.

          INCX is INTEGER
          The increment between successive values of IPIV.  If IPIV
          is negative, the pivots are applied in reverse order.

  Modified by
   R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA