Intel® oneAPI Math Kernel Library Developer Reference - Fortran

?lapst

Sorts the numbers in increasing or decreasing order.

Syntax

call slapst (id, n, d, indx, info )

call dlapst (id, n, d, indx, info )

Description

?lapst is a modified version of the LAPACK routine ?lasrt.

Define a permutation indx that sorts 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 232.

Input Parameters

id

CHARACTER*1.

= 'I': sort d in increasing order;

= 'D': sort d in decreasing order.

n

INTEGER.

The length of the array d.

d

REAL for slapst

DOUBLE PRECISION for dlapst

Array, size (n)

The array to be sorted.

Output Parameters

indx

INTEGER.

Array, size (n).

The permutation which sorts the array d.

info

INTEGER.

= 0: successful exit

< 0: if info = -i, the i-th argument had an illegal value