LAPACK  3.10.0
LAPACK: Linear Algebra PACKage
slaord.f
Go to the documentation of this file.
1 *> \brief \b SLAORD
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 * Definition:
9 * ===========
10 *
11 * SUBROUTINE SLAORD( JOB, N, X, INCX )
12 *
13 * .. Scalar Arguments ..
14 * CHARACTER JOB
15 * INTEGER INCX, N
16 * ..
17 * .. Array Arguments ..
18 * REAL X( * )
19 * ..
20 *
21 *
22 *> \par Purpose:
23 * =============
24 *>
25 *> \verbatim
26 *>
27 *> SLAORD sorts the elements of a vector x in increasing or decreasing
28 *> order.
29 *> \endverbatim
30 *
31 * Arguments:
32 * ==========
33 *
34 *> \param[in] JOB
35 *> \verbatim
36 *> JOB is CHARACTER
37 *> = 'I': Sort in increasing order
38 *> = 'D': Sort in decreasing order
39 *> \endverbatim
40 *>
41 *> \param[in] N
42 *> \verbatim
43 *> N is INTEGER
44 *> The length of the vector X.
45 *> \endverbatim
46 *>
47 *> \param[in,out] X
48 *> \verbatim
49 *> X is REAL array, dimension
50 *> (1+(N-1)*INCX)
51 *> On entry, the vector of length n to be sorted.
52 *> On exit, the vector x is sorted in the prescribed order.
53 *> \endverbatim
54 *>
55 *> \param[in] INCX
56 *> \verbatim
57 *> INCX is INTEGER
58 *> The spacing between successive elements of X. INCX >= 0.
59 *> \endverbatim
60 *
61 * Authors:
62 * ========
63 *
64 *> \author Univ. of Tennessee
65 *> \author Univ. of California Berkeley
66 *> \author Univ. of Colorado Denver
67 *> \author NAG Ltd.
68 *
69 *> \ingroup single_lin
70 *
71 * =====================================================================
72  SUBROUTINE slaord( JOB, N, X, INCX )
73 *
74 * -- LAPACK test routine --
75 * -- LAPACK is a software package provided by Univ. of Tennessee, --
76 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
77 *
78 * .. Scalar Arguments ..
79  CHARACTER JOB
80  INTEGER INCX, N
81 * ..
82 * .. Array Arguments ..
83  REAL X( * )
84 * ..
85 *
86 * =====================================================================
87 *
88 * .. Local Scalars ..
89  INTEGER I, INC, IX, IXNEXT
90  REAL TEMP
91 * ..
92 * .. External Functions ..
93  LOGICAL LSAME
94  EXTERNAL lsame
95 * ..
96 * .. Intrinsic Functions ..
97  INTRINSIC abs
98 * ..
99 * .. Executable Statements ..
100 *
101  inc = abs( incx )
102  IF( lsame( job, 'I' ) ) THEN
103 *
104 * Sort in increasing order
105 *
106  DO 20 i = 2, n
107  ix = 1 + ( i-1 )*inc
108  10 CONTINUE
109  IF( ix.EQ.1 )
110  $ GO TO 20
111  ixnext = ix - inc
112  IF( x( ix ).GT.x( ixnext ) ) THEN
113  GO TO 20
114  ELSE
115  temp = x( ix )
116  x( ix ) = x( ixnext )
117  x( ixnext ) = temp
118  END IF
119  ix = ixnext
120  GO TO 10
121  20 CONTINUE
122 *
123  ELSE IF( lsame( job, 'D' ) ) THEN
124 *
125 * Sort in decreasing order
126 *
127  DO 40 i = 2, n
128  ix = 1 + ( i-1 )*inc
129  30 CONTINUE
130  IF( ix.EQ.1 )
131  $ GO TO 40
132  ixnext = ix - inc
133  IF( x( ix ).LT.x( ixnext ) ) THEN
134  GO TO 40
135  ELSE
136  temp = x( ix )
137  x( ix ) = x( ixnext )
138  x( ixnext ) = temp
139  END IF
140  ix = ixnext
141  GO TO 30
142  40 CONTINUE
143  END IF
144  RETURN
145 *
146 * End of SLAORD
147 *
148  END
subroutine slaord(JOB, N, X, INCX)
SLAORD
Definition: slaord.f:73