DLASRT2 - the numbers in D in increasing order (if ID = ’I’) or in
decreasing order (if ID = ’D’ )
SUBROUTINE DLASRT2( ID, N, D, KEY, INFO )
INTEGER INFO, N
INTEGER KEY( * )
DOUBLE PRECISION D( * )
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.
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) DOUBLE PRECISION 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