1 SUBROUTINE DLASRT( ID, N, D, INFO )
2 *
3 * -- LAPACK routine (version 3.2) --
4 * -- LAPACK is a software package provided by Univ. of Tennessee, --
5 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
6 * November 2006
7 *
8 * .. Scalar Arguments ..
9 CHARACTER ID
10 INTEGER INFO, N
11 * ..
12 * .. Array Arguments ..
13 DOUBLE PRECISION D( * )
14 * ..
15 *
16 * Purpose
17 * =======
18 *
19 * Sort the numbers in D in increasing order (if ID = 'I') or
20 * in decreasing order (if ID = 'D' ).
21 *
22 * Use Quick Sort, reverting to Insertion sort on arrays of
23 * size <= 20. Dimension of STACK limits N to about 2**32.
24 *
25 * Arguments
26 * =========
27 *
28 * ID (input) CHARACTER*1
29 * = 'I': sort D in increasing order;
30 * = 'D': sort D in decreasing order.
31 *
32 * N (input) INTEGER
33 * The length of the array D.
34 *
35 * D (input/output) DOUBLE PRECISION array, dimension (N)
36 * On entry, the array to be sorted.
37 * On exit, D has been sorted into increasing order
38 * (D(1) <= ... <= D(N) ) or into decreasing order
39 * (D(1) >= ... >= D(N) ), depending on ID.
40 *
41 * INFO (output) INTEGER
42 * = 0: successful exit
43 * < 0: if INFO = -i, the i-th argument had an illegal value
44 *
45 * =====================================================================
46 *
47 * .. Parameters ..
48 INTEGER SELECT
49 PARAMETER ( SELECT = 20 )
50 * ..
51 * .. Local Scalars ..
52 INTEGER DIR, ENDD, I, J, START, STKPNT
53 DOUBLE PRECISION D1, D2, D3, DMNMX, TMP
54 * ..
55 * .. Local Arrays ..
56 INTEGER STACK( 2, 32 )
57 * ..
58 * .. External Functions ..
59 LOGICAL LSAME
60 EXTERNAL LSAME
61 * ..
62 * .. External Subroutines ..
63 EXTERNAL XERBLA
64 * ..
65 * .. Executable Statements ..
66 *
67 * Test the input paramters.
68 *
69 INFO = 0
70 DIR = -1
71 IF( LSAME( ID, 'D' ) ) THEN
72 DIR = 0
73 ELSE IF( LSAME( ID, 'I' ) ) THEN
74 DIR = 1
75 END IF
76 IF( DIR.EQ.-1 ) THEN
77 INFO = -1
78 ELSE IF( N.LT.0 ) THEN
79 INFO = -2
80 END IF
81 IF( INFO.NE.0 ) THEN
82 CALL XERBLA( 'DLASRT', -INFO )
83 RETURN
84 END IF
85 *
86 * Quick return if possible
87 *
88 IF( N.LE.1 )
89 $ RETURN
90 *
91 STKPNT = 1
92 STACK( 1, 1 ) = 1
93 STACK( 2, 1 ) = N
94 10 CONTINUE
95 START = STACK( 1, STKPNT )
96 ENDD = STACK( 2, STKPNT )
97 STKPNT = STKPNT - 1
98 IF( ENDD-START.LE.SELECT .AND. ENDD-START.GT.0 ) THEN
99 *
100 * Do Insertion sort on D( START:ENDD )
101 *
102 IF( DIR.EQ.0 ) THEN
103 *
104 * Sort into decreasing order
105 *
106 DO 30 I = START + 1, ENDD
107 DO 20 J = I, START + 1, -1
108 IF( D( J ).GT.D( J-1 ) ) THEN
109 DMNMX = D( J )
110 D( J ) = D( J-1 )
111 D( J-1 ) = DMNMX
112 ELSE
113 GO TO 30
114 END IF
115 20 CONTINUE
116 30 CONTINUE
117 *
118 ELSE
119 *
120 * Sort into increasing order
121 *
122 DO 50 I = START + 1, ENDD
123 DO 40 J = I, START + 1, -1
124 IF( D( J ).LT.D( J-1 ) ) THEN
125 DMNMX = D( J )
126 D( J ) = D( J-1 )
127 D( J-1 ) = DMNMX
128 ELSE
129 GO TO 50
130 END IF
131 40 CONTINUE
132 50 CONTINUE
133 *
134 END IF
135 *
136 ELSE IF( ENDD-START.GT.SELECT ) THEN
137 *
138 * Partition D( START:ENDD ) and stack parts, largest one first
139 *
140 * Choose partition entry as median of 3
141 *
142 D1 = D( START )
143 D2 = D( ENDD )
144 I = ( START+ENDD ) / 2
145 D3 = D( I )
146 IF( D1.LT.D2 ) THEN
147 IF( D3.LT.D1 ) THEN
148 DMNMX = D1
149 ELSE IF( D3.LT.D2 ) THEN
150 DMNMX = D3
151 ELSE
152 DMNMX = D2
153 END IF
154 ELSE
155 IF( D3.LT.D2 ) THEN
156 DMNMX = D2
157 ELSE IF( D3.LT.D1 ) THEN
158 DMNMX = D3
159 ELSE
160 DMNMX = D1
161 END IF
162 END IF
163 *
164 IF( DIR.EQ.0 ) THEN
165 *
166 * Sort into decreasing order
167 *
168 I = START - 1
169 J = ENDD + 1
170 60 CONTINUE
171 70 CONTINUE
172 J = J - 1
173 IF( D( J ).LT.DMNMX )
174 $ GO TO 70
175 80 CONTINUE
176 I = I + 1
177 IF( D( I ).GT.DMNMX )
178 $ GO TO 80
179 IF( I.LT.J ) THEN
180 TMP = D( I )
181 D( I ) = D( J )
182 D( J ) = TMP
183 GO TO 60
184 END IF
185 IF( J-START.GT.ENDD-J-1 ) THEN
186 STKPNT = STKPNT + 1
187 STACK( 1, STKPNT ) = START
188 STACK( 2, STKPNT ) = J
189 STKPNT = STKPNT + 1
190 STACK( 1, STKPNT ) = J + 1
191 STACK( 2, STKPNT ) = ENDD
192 ELSE
193 STKPNT = STKPNT + 1
194 STACK( 1, STKPNT ) = J + 1
195 STACK( 2, STKPNT ) = ENDD
196 STKPNT = STKPNT + 1
197 STACK( 1, STKPNT ) = START
198 STACK( 2, STKPNT ) = J
199 END IF
200 ELSE
201 *
202 * Sort into increasing order
203 *
204 I = START - 1
205 J = ENDD + 1
206 90 CONTINUE
207 100 CONTINUE
208 J = J - 1
209 IF( D( J ).GT.DMNMX )
210 $ GO TO 100
211 110 CONTINUE
212 I = I + 1
213 IF( D( I ).LT.DMNMX )
214 $ GO TO 110
215 IF( I.LT.J ) THEN
216 TMP = D( I )
217 D( I ) = D( J )
218 D( J ) = TMP
219 GO TO 90
220 END IF
221 IF( J-START.GT.ENDD-J-1 ) THEN
222 STKPNT = STKPNT + 1
223 STACK( 1, STKPNT ) = START
224 STACK( 2, STKPNT ) = J
225 STKPNT = STKPNT + 1
226 STACK( 1, STKPNT ) = J + 1
227 STACK( 2, STKPNT ) = ENDD
228 ELSE
229 STKPNT = STKPNT + 1
230 STACK( 1, STKPNT ) = J + 1
231 STACK( 2, STKPNT ) = ENDD
232 STKPNT = STKPNT + 1
233 STACK( 1, STKPNT ) = START
234 STACK( 2, STKPNT ) = J
235 END IF
236 END IF
237 END IF
238 IF( STKPNT.GT.0 )
239 $ GO TO 10
240 RETURN
241 *
242 * End of DLASRT
243 *
244 END
2 *
3 * -- LAPACK routine (version 3.2) --
4 * -- LAPACK is a software package provided by Univ. of Tennessee, --
5 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
6 * November 2006
7 *
8 * .. Scalar Arguments ..
9 CHARACTER ID
10 INTEGER INFO, N
11 * ..
12 * .. Array Arguments ..
13 DOUBLE PRECISION D( * )
14 * ..
15 *
16 * Purpose
17 * =======
18 *
19 * Sort the numbers in D in increasing order (if ID = 'I') or
20 * in decreasing order (if ID = 'D' ).
21 *
22 * Use Quick Sort, reverting to Insertion sort on arrays of
23 * size <= 20. Dimension of STACK limits N to about 2**32.
24 *
25 * Arguments
26 * =========
27 *
28 * ID (input) CHARACTER*1
29 * = 'I': sort D in increasing order;
30 * = 'D': sort D in decreasing order.
31 *
32 * N (input) INTEGER
33 * The length of the array D.
34 *
35 * D (input/output) DOUBLE PRECISION array, dimension (N)
36 * On entry, the array to be sorted.
37 * On exit, D has been sorted into increasing order
38 * (D(1) <= ... <= D(N) ) or into decreasing order
39 * (D(1) >= ... >= D(N) ), depending on ID.
40 *
41 * INFO (output) INTEGER
42 * = 0: successful exit
43 * < 0: if INFO = -i, the i-th argument had an illegal value
44 *
45 * =====================================================================
46 *
47 * .. Parameters ..
48 INTEGER SELECT
49 PARAMETER ( SELECT = 20 )
50 * ..
51 * .. Local Scalars ..
52 INTEGER DIR, ENDD, I, J, START, STKPNT
53 DOUBLE PRECISION D1, D2, D3, DMNMX, TMP
54 * ..
55 * .. Local Arrays ..
56 INTEGER STACK( 2, 32 )
57 * ..
58 * .. External Functions ..
59 LOGICAL LSAME
60 EXTERNAL LSAME
61 * ..
62 * .. External Subroutines ..
63 EXTERNAL XERBLA
64 * ..
65 * .. Executable Statements ..
66 *
67 * Test the input paramters.
68 *
69 INFO = 0
70 DIR = -1
71 IF( LSAME( ID, 'D' ) ) THEN
72 DIR = 0
73 ELSE IF( LSAME( ID, 'I' ) ) THEN
74 DIR = 1
75 END IF
76 IF( DIR.EQ.-1 ) THEN
77 INFO = -1
78 ELSE IF( N.LT.0 ) THEN
79 INFO = -2
80 END IF
81 IF( INFO.NE.0 ) THEN
82 CALL XERBLA( 'DLASRT', -INFO )
83 RETURN
84 END IF
85 *
86 * Quick return if possible
87 *
88 IF( N.LE.1 )
89 $ RETURN
90 *
91 STKPNT = 1
92 STACK( 1, 1 ) = 1
93 STACK( 2, 1 ) = N
94 10 CONTINUE
95 START = STACK( 1, STKPNT )
96 ENDD = STACK( 2, STKPNT )
97 STKPNT = STKPNT - 1
98 IF( ENDD-START.LE.SELECT .AND. ENDD-START.GT.0 ) THEN
99 *
100 * Do Insertion sort on D( START:ENDD )
101 *
102 IF( DIR.EQ.0 ) THEN
103 *
104 * Sort into decreasing order
105 *
106 DO 30 I = START + 1, ENDD
107 DO 20 J = I, START + 1, -1
108 IF( D( J ).GT.D( J-1 ) ) THEN
109 DMNMX = D( J )
110 D( J ) = D( J-1 )
111 D( J-1 ) = DMNMX
112 ELSE
113 GO TO 30
114 END IF
115 20 CONTINUE
116 30 CONTINUE
117 *
118 ELSE
119 *
120 * Sort into increasing order
121 *
122 DO 50 I = START + 1, ENDD
123 DO 40 J = I, START + 1, -1
124 IF( D( J ).LT.D( J-1 ) ) THEN
125 DMNMX = D( J )
126 D( J ) = D( J-1 )
127 D( J-1 ) = DMNMX
128 ELSE
129 GO TO 50
130 END IF
131 40 CONTINUE
132 50 CONTINUE
133 *
134 END IF
135 *
136 ELSE IF( ENDD-START.GT.SELECT ) THEN
137 *
138 * Partition D( START:ENDD ) and stack parts, largest one first
139 *
140 * Choose partition entry as median of 3
141 *
142 D1 = D( START )
143 D2 = D( ENDD )
144 I = ( START+ENDD ) / 2
145 D3 = D( I )
146 IF( D1.LT.D2 ) THEN
147 IF( D3.LT.D1 ) THEN
148 DMNMX = D1
149 ELSE IF( D3.LT.D2 ) THEN
150 DMNMX = D3
151 ELSE
152 DMNMX = D2
153 END IF
154 ELSE
155 IF( D3.LT.D2 ) THEN
156 DMNMX = D2
157 ELSE IF( D3.LT.D1 ) THEN
158 DMNMX = D3
159 ELSE
160 DMNMX = D1
161 END IF
162 END IF
163 *
164 IF( DIR.EQ.0 ) THEN
165 *
166 * Sort into decreasing order
167 *
168 I = START - 1
169 J = ENDD + 1
170 60 CONTINUE
171 70 CONTINUE
172 J = J - 1
173 IF( D( J ).LT.DMNMX )
174 $ GO TO 70
175 80 CONTINUE
176 I = I + 1
177 IF( D( I ).GT.DMNMX )
178 $ GO TO 80
179 IF( I.LT.J ) THEN
180 TMP = D( I )
181 D( I ) = D( J )
182 D( J ) = TMP
183 GO TO 60
184 END IF
185 IF( J-START.GT.ENDD-J-1 ) THEN
186 STKPNT = STKPNT + 1
187 STACK( 1, STKPNT ) = START
188 STACK( 2, STKPNT ) = J
189 STKPNT = STKPNT + 1
190 STACK( 1, STKPNT ) = J + 1
191 STACK( 2, STKPNT ) = ENDD
192 ELSE
193 STKPNT = STKPNT + 1
194 STACK( 1, STKPNT ) = J + 1
195 STACK( 2, STKPNT ) = ENDD
196 STKPNT = STKPNT + 1
197 STACK( 1, STKPNT ) = START
198 STACK( 2, STKPNT ) = J
199 END IF
200 ELSE
201 *
202 * Sort into increasing order
203 *
204 I = START - 1
205 J = ENDD + 1
206 90 CONTINUE
207 100 CONTINUE
208 J = J - 1
209 IF( D( J ).GT.DMNMX )
210 $ GO TO 100
211 110 CONTINUE
212 I = I + 1
213 IF( D( I ).LT.DMNMX )
214 $ GO TO 110
215 IF( I.LT.J ) THEN
216 TMP = D( I )
217 D( I ) = D( J )
218 D( J ) = TMP
219 GO TO 90
220 END IF
221 IF( J-START.GT.ENDD-J-1 ) THEN
222 STKPNT = STKPNT + 1
223 STACK( 1, STKPNT ) = START
224 STACK( 2, STKPNT ) = J
225 STKPNT = STKPNT + 1
226 STACK( 1, STKPNT ) = J + 1
227 STACK( 2, STKPNT ) = ENDD
228 ELSE
229 STKPNT = STKPNT + 1
230 STACK( 1, STKPNT ) = J + 1
231 STACK( 2, STKPNT ) = ENDD
232 STKPNT = STKPNT + 1
233 STACK( 1, STKPNT ) = START
234 STACK( 2, STKPNT ) = J
235 END IF
236 END IF
237 END IF
238 IF( STKPNT.GT.0 )
239 $ GO TO 10
240 RETURN
241 *
242 * End of DLASRT
243 *
244 END