Contents
blas_dsortv - sorts a real (double precision) vector X in
increasing or decreasing order using quick sort algorithm
and overwrite P with the permutation vector
SUBROUTINE BLAS_DSORTV (SORT, N, X, INCX, P, INCP)
INTEGER SORT
INTEGER N
REAL*8 X(*)
INTEGER INCX
INTEGER P(*)
INTEGER INCP
SUBROUTINE BLAS_DSORTV_64 (SORT, N, X, INCX, P, INCP)
INTEGER*8 SORT
INTEGER*8 N
REAL*8 X(*)
INTEGER*8 INCX
INTEGER*8 P(*)
INTEGER*8 INCP
F95 INTERFACE
SUBROUTINE SORTV (X [, SORT] [, P])
USE SUNPERF
SUBROUTINE SORTV_64 (X [, SORT] [, P])
USE SUNPERF
SORTV covers the functionality of SORT
SORT (input) INTEGER, indicating sort directions
SORT = 0, descending
SORT = 1, ascending
SORT = other value, error
SORT is default to 1 for F95 INTERFACE
N (input) INTEGER, the number of elements to be sorted in X
If N <= 1, the subroutine returns without trying
to sort X.
X (input/output) REAL*8((N-1)*|INCX|+1), the array to be
sorted
Minimum size (N-1)*|INCX|+1 is required
INCX (input) INTEGER, increment for X
INCX must not be zero. INCX could be negative. If
INCX < 0, change the sorting direction defined by
SORT. That is
If SORT = 0, let SORT = 1, INCX = |INCX|;
If SORT = 1, let SORT = 0, INCX = |INCX|.
P (output) INTEGER((N-1)*|INCP|+1), the permutation (index)
vector recording the details of the interchanges
of the elements of X during sorting. That is X =
P*X. In this implementation, P contains the index
of sorted X.
INCP (input) INTEGER, increment fpr P
INCP must not be zero. INCP could be negative. If
INCP < 0, store P(i) in reverse order. That is
If INCP > 0,
if INCX > 0,
sorted X((i-1)*INCX+1) = X(P((i-1)*INCP+1)),
if INCX < 0,
sorted X((N-i)*|INCX|+1) = X(P((i-1)*INCP+1));
If INCP < 0,
if INCX > 0,
sorted X((i-1)*INCX+1) = X(P((N-i)*|INCP|+1)),
if INCX < 0,
sorted X((N-i)*|INCX|+1)
= X(P((N-i)*|INCP|+1)).
blas_dsort(3P), blas_dpermute(3P)