NAME

       SLASRT2 - the numbers in D in increasing order (if ID = 'I') or in decreasing order (if ID
       = 'D' )

SYNOPSIS

       SUBROUTINE SLASRT2( ID, N, D, KEY, INFO )

           CHARACTER       ID

           INTEGER         INFO, N

           INTEGER         KEY( * )

           REAL            D( * )

PURPOSE

       Sort the numbers in D in increasing order (if ID = 'I') or in decreasing order  (if  ID  =
       'D' ).

       Use Quick Sort, reverting to Insertion sort on arrays of
       size <= 20. Dimension of STACK limits N to about 2**32.

ARGUMENTS

       ID      (input) CHARACTER*1
               = 'I': sort D in increasing order;
               = 'D': sort D in decreasing order.

       N       (input) INTEGER
               The length of the array D.

       D       (input/output) REAL array, dimension (N)
               On  entry,  the  array  to  be sorted.  On exit, D has been sorted into increasing
               order (D(1) <= ... <= D(N) ) or into decreasing order (D(1)  >=  ...  >=  D(N)  ),
               depending on ID.

       KEY     (input/output) INTEGER array, dimension (N)
               On  entry,  KEY contains a key to each of the entries in D() Typically, KEY(I) = I
               for all I On exit, KEY is permuted in exactly the same manner as D() was  permuted
               from  input to output Therefore, if KEY(I) = I for all I upon input, then D_out(I)
               = D_in(KEY(I))

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