root / src / lapack / double / dlasrt.f @ 8
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| 1 | 1 | pfleura2 | SUBROUTINE DLASRT( ID, N, D, INFO ) |
|---|---|---|---|
| 2 | 1 | pfleura2 | * |
| 3 | 1 | pfleura2 | * -- LAPACK routine (version 3.2) -- |
| 4 | 1 | pfleura2 | * -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 5 | 1 | pfleura2 | * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 6 | 1 | pfleura2 | * November 2006 |
| 7 | 1 | pfleura2 | * |
| 8 | 1 | pfleura2 | * .. Scalar Arguments .. |
| 9 | 1 | pfleura2 | CHARACTER ID |
| 10 | 1 | pfleura2 | INTEGER INFO, N |
| 11 | 1 | pfleura2 | * .. |
| 12 | 1 | pfleura2 | * .. Array Arguments .. |
| 13 | 1 | pfleura2 | DOUBLE PRECISION D( * ) |
| 14 | 1 | pfleura2 | * .. |
| 15 | 1 | pfleura2 | * |
| 16 | 1 | pfleura2 | * Purpose |
| 17 | 1 | pfleura2 | * ======= |
| 18 | 1 | pfleura2 | * |
| 19 | 1 | pfleura2 | * Sort the numbers in D in increasing order (if ID = 'I') or |
| 20 | 1 | pfleura2 | * in decreasing order (if ID = 'D' ). |
| 21 | 1 | pfleura2 | * |
| 22 | 1 | pfleura2 | * Use Quick Sort, reverting to Insertion sort on arrays of |
| 23 | 1 | pfleura2 | * size <= 20. Dimension of STACK limits N to about 2**32. |
| 24 | 1 | pfleura2 | * |
| 25 | 1 | pfleura2 | * Arguments |
| 26 | 1 | pfleura2 | * ========= |
| 27 | 1 | pfleura2 | * |
| 28 | 1 | pfleura2 | * ID (input) CHARACTER*1 |
| 29 | 1 | pfleura2 | * = 'I': sort D in increasing order; |
| 30 | 1 | pfleura2 | * = 'D': sort D in decreasing order. |
| 31 | 1 | pfleura2 | * |
| 32 | 1 | pfleura2 | * N (input) INTEGER |
| 33 | 1 | pfleura2 | * The length of the array D. |
| 34 | 1 | pfleura2 | * |
| 35 | 1 | pfleura2 | * D (input/output) DOUBLE PRECISION array, dimension (N) |
| 36 | 1 | pfleura2 | * On entry, the array to be sorted. |
| 37 | 1 | pfleura2 | * On exit, D has been sorted into increasing order |
| 38 | 1 | pfleura2 | * (D(1) <= ... <= D(N) ) or into decreasing order |
| 39 | 1 | pfleura2 | * (D(1) >= ... >= D(N) ), depending on ID. |
| 40 | 1 | pfleura2 | * |
| 41 | 1 | pfleura2 | * INFO (output) INTEGER |
| 42 | 1 | pfleura2 | * = 0: successful exit |
| 43 | 1 | pfleura2 | * < 0: if INFO = -i, the i-th argument had an illegal value |
| 44 | 1 | pfleura2 | * |
| 45 | 1 | pfleura2 | * ===================================================================== |
| 46 | 1 | pfleura2 | * |
| 47 | 1 | pfleura2 | * .. Parameters .. |
| 48 | 1 | pfleura2 | INTEGER SELECT |
| 49 | 1 | pfleura2 | PARAMETER ( SELECT = 20 ) |
| 50 | 1 | pfleura2 | * .. |
| 51 | 1 | pfleura2 | * .. Local Scalars .. |
| 52 | 1 | pfleura2 | INTEGER DIR, ENDD, I, J, START, STKPNT |
| 53 | 1 | pfleura2 | DOUBLE PRECISION D1, D2, D3, DMNMX, TMP |
| 54 | 1 | pfleura2 | * .. |
| 55 | 1 | pfleura2 | * .. Local Arrays .. |
| 56 | 1 | pfleura2 | INTEGER STACK( 2, 32 ) |
| 57 | 1 | pfleura2 | * .. |
| 58 | 1 | pfleura2 | * .. External Functions .. |
| 59 | 1 | pfleura2 | LOGICAL LSAME |
| 60 | 1 | pfleura2 | EXTERNAL LSAME |
| 61 | 1 | pfleura2 | * .. |
| 62 | 1 | pfleura2 | * .. External Subroutines .. |
| 63 | 1 | pfleura2 | EXTERNAL XERBLA |
| 64 | 1 | pfleura2 | * .. |
| 65 | 1 | pfleura2 | * .. Executable Statements .. |
| 66 | 1 | pfleura2 | * |
| 67 | 1 | pfleura2 | * Test the input paramters. |
| 68 | 1 | pfleura2 | * |
| 69 | 1 | pfleura2 | INFO = 0 |
| 70 | 1 | pfleura2 | DIR = -1 |
| 71 | 1 | pfleura2 | IF( LSAME( ID, 'D' ) ) THEN |
| 72 | 1 | pfleura2 | DIR = 0 |
| 73 | 1 | pfleura2 | ELSE IF( LSAME( ID, 'I' ) ) THEN |
| 74 | 1 | pfleura2 | DIR = 1 |
| 75 | 1 | pfleura2 | END IF |
| 76 | 1 | pfleura2 | IF( DIR.EQ.-1 ) THEN |
| 77 | 1 | pfleura2 | INFO = -1 |
| 78 | 1 | pfleura2 | ELSE IF( N.LT.0 ) THEN |
| 79 | 1 | pfleura2 | INFO = -2 |
| 80 | 1 | pfleura2 | END IF |
| 81 | 1 | pfleura2 | IF( INFO.NE.0 ) THEN |
| 82 | 1 | pfleura2 | CALL XERBLA( 'DLASRT', -INFO ) |
| 83 | 1 | pfleura2 | RETURN |
| 84 | 1 | pfleura2 | END IF |
| 85 | 1 | pfleura2 | * |
| 86 | 1 | pfleura2 | * Quick return if possible |
| 87 | 1 | pfleura2 | * |
| 88 | 1 | pfleura2 | IF( N.LE.1 ) |
| 89 | 1 | pfleura2 | $ RETURN |
| 90 | 1 | pfleura2 | * |
| 91 | 1 | pfleura2 | STKPNT = 1 |
| 92 | 1 | pfleura2 | STACK( 1, 1 ) = 1 |
| 93 | 1 | pfleura2 | STACK( 2, 1 ) = N |
| 94 | 1 | pfleura2 | 10 CONTINUE |
| 95 | 1 | pfleura2 | START = STACK( 1, STKPNT ) |
| 96 | 1 | pfleura2 | ENDD = STACK( 2, STKPNT ) |
| 97 | 1 | pfleura2 | STKPNT = STKPNT - 1 |
| 98 | 1 | pfleura2 | IF( ENDD-START.LE.SELECT .AND. ENDD-START.GT.0 ) THEN |
| 99 | 1 | pfleura2 | * |
| 100 | 1 | pfleura2 | * Do Insertion sort on D( START:ENDD ) |
| 101 | 1 | pfleura2 | * |
| 102 | 1 | pfleura2 | IF( DIR.EQ.0 ) THEN |
| 103 | 1 | pfleura2 | * |
| 104 | 1 | pfleura2 | * Sort into decreasing order |
| 105 | 1 | pfleura2 | * |
| 106 | 1 | pfleura2 | DO 30 I = START + 1, ENDD |
| 107 | 1 | pfleura2 | DO 20 J = I, START + 1, -1 |
| 108 | 1 | pfleura2 | IF( D( J ).GT.D( J-1 ) ) THEN |
| 109 | 1 | pfleura2 | DMNMX = D( J ) |
| 110 | 1 | pfleura2 | D( J ) = D( J-1 ) |
| 111 | 1 | pfleura2 | D( J-1 ) = DMNMX |
| 112 | 1 | pfleura2 | ELSE |
| 113 | 1 | pfleura2 | GO TO 30 |
| 114 | 1 | pfleura2 | END IF |
| 115 | 1 | pfleura2 | 20 CONTINUE |
| 116 | 1 | pfleura2 | 30 CONTINUE |
| 117 | 1 | pfleura2 | * |
| 118 | 1 | pfleura2 | ELSE |
| 119 | 1 | pfleura2 | * |
| 120 | 1 | pfleura2 | * Sort into increasing order |
| 121 | 1 | pfleura2 | * |
| 122 | 1 | pfleura2 | DO 50 I = START + 1, ENDD |
| 123 | 1 | pfleura2 | DO 40 J = I, START + 1, -1 |
| 124 | 1 | pfleura2 | IF( D( J ).LT.D( J-1 ) ) THEN |
| 125 | 1 | pfleura2 | DMNMX = D( J ) |
| 126 | 1 | pfleura2 | D( J ) = D( J-1 ) |
| 127 | 1 | pfleura2 | D( J-1 ) = DMNMX |
| 128 | 1 | pfleura2 | ELSE |
| 129 | 1 | pfleura2 | GO TO 50 |
| 130 | 1 | pfleura2 | END IF |
| 131 | 1 | pfleura2 | 40 CONTINUE |
| 132 | 1 | pfleura2 | 50 CONTINUE |
| 133 | 1 | pfleura2 | * |
| 134 | 1 | pfleura2 | END IF |
| 135 | 1 | pfleura2 | * |
| 136 | 1 | pfleura2 | ELSE IF( ENDD-START.GT.SELECT ) THEN |
| 137 | 1 | pfleura2 | * |
| 138 | 1 | pfleura2 | * Partition D( START:ENDD ) and stack parts, largest one first |
| 139 | 1 | pfleura2 | * |
| 140 | 1 | pfleura2 | * Choose partition entry as median of 3 |
| 141 | 1 | pfleura2 | * |
| 142 | 1 | pfleura2 | D1 = D( START ) |
| 143 | 1 | pfleura2 | D2 = D( ENDD ) |
| 144 | 1 | pfleura2 | I = ( START+ENDD ) / 2 |
| 145 | 1 | pfleura2 | D3 = D( I ) |
| 146 | 1 | pfleura2 | IF( D1.LT.D2 ) THEN |
| 147 | 1 | pfleura2 | IF( D3.LT.D1 ) THEN |
| 148 | 1 | pfleura2 | DMNMX = D1 |
| 149 | 1 | pfleura2 | ELSE IF( D3.LT.D2 ) THEN |
| 150 | 1 | pfleura2 | DMNMX = D3 |
| 151 | 1 | pfleura2 | ELSE |
| 152 | 1 | pfleura2 | DMNMX = D2 |
| 153 | 1 | pfleura2 | END IF |
| 154 | 1 | pfleura2 | ELSE |
| 155 | 1 | pfleura2 | IF( D3.LT.D2 ) THEN |
| 156 | 1 | pfleura2 | DMNMX = D2 |
| 157 | 1 | pfleura2 | ELSE IF( D3.LT.D1 ) THEN |
| 158 | 1 | pfleura2 | DMNMX = D3 |
| 159 | 1 | pfleura2 | ELSE |
| 160 | 1 | pfleura2 | DMNMX = D1 |
| 161 | 1 | pfleura2 | END IF |
| 162 | 1 | pfleura2 | END IF |
| 163 | 1 | pfleura2 | * |
| 164 | 1 | pfleura2 | IF( DIR.EQ.0 ) THEN |
| 165 | 1 | pfleura2 | * |
| 166 | 1 | pfleura2 | * Sort into decreasing order |
| 167 | 1 | pfleura2 | * |
| 168 | 1 | pfleura2 | I = START - 1 |
| 169 | 1 | pfleura2 | J = ENDD + 1 |
| 170 | 1 | pfleura2 | 60 CONTINUE |
| 171 | 1 | pfleura2 | 70 CONTINUE |
| 172 | 1 | pfleura2 | J = J - 1 |
| 173 | 1 | pfleura2 | IF( D( J ).LT.DMNMX ) |
| 174 | 1 | pfleura2 | $ GO TO 70 |
| 175 | 1 | pfleura2 | 80 CONTINUE |
| 176 | 1 | pfleura2 | I = I + 1 |
| 177 | 1 | pfleura2 | IF( D( I ).GT.DMNMX ) |
| 178 | 1 | pfleura2 | $ GO TO 80 |
| 179 | 1 | pfleura2 | IF( I.LT.J ) THEN |
| 180 | 1 | pfleura2 | TMP = D( I ) |
| 181 | 1 | pfleura2 | D( I ) = D( J ) |
| 182 | 1 | pfleura2 | D( J ) = TMP |
| 183 | 1 | pfleura2 | GO TO 60 |
| 184 | 1 | pfleura2 | END IF |
| 185 | 1 | pfleura2 | IF( J-START.GT.ENDD-J-1 ) THEN |
| 186 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 187 | 1 | pfleura2 | STACK( 1, STKPNT ) = START |
| 188 | 1 | pfleura2 | STACK( 2, STKPNT ) = J |
| 189 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 190 | 1 | pfleura2 | STACK( 1, STKPNT ) = J + 1 |
| 191 | 1 | pfleura2 | STACK( 2, STKPNT ) = ENDD |
| 192 | 1 | pfleura2 | ELSE |
| 193 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 194 | 1 | pfleura2 | STACK( 1, STKPNT ) = J + 1 |
| 195 | 1 | pfleura2 | STACK( 2, STKPNT ) = ENDD |
| 196 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 197 | 1 | pfleura2 | STACK( 1, STKPNT ) = START |
| 198 | 1 | pfleura2 | STACK( 2, STKPNT ) = J |
| 199 | 1 | pfleura2 | END IF |
| 200 | 1 | pfleura2 | ELSE |
| 201 | 1 | pfleura2 | * |
| 202 | 1 | pfleura2 | * Sort into increasing order |
| 203 | 1 | pfleura2 | * |
| 204 | 1 | pfleura2 | I = START - 1 |
| 205 | 1 | pfleura2 | J = ENDD + 1 |
| 206 | 1 | pfleura2 | 90 CONTINUE |
| 207 | 1 | pfleura2 | 100 CONTINUE |
| 208 | 1 | pfleura2 | J = J - 1 |
| 209 | 1 | pfleura2 | IF( D( J ).GT.DMNMX ) |
| 210 | 1 | pfleura2 | $ GO TO 100 |
| 211 | 1 | pfleura2 | 110 CONTINUE |
| 212 | 1 | pfleura2 | I = I + 1 |
| 213 | 1 | pfleura2 | IF( D( I ).LT.DMNMX ) |
| 214 | 1 | pfleura2 | $ GO TO 110 |
| 215 | 1 | pfleura2 | IF( I.LT.J ) THEN |
| 216 | 1 | pfleura2 | TMP = D( I ) |
| 217 | 1 | pfleura2 | D( I ) = D( J ) |
| 218 | 1 | pfleura2 | D( J ) = TMP |
| 219 | 1 | pfleura2 | GO TO 90 |
| 220 | 1 | pfleura2 | END IF |
| 221 | 1 | pfleura2 | IF( J-START.GT.ENDD-J-1 ) THEN |
| 222 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 223 | 1 | pfleura2 | STACK( 1, STKPNT ) = START |
| 224 | 1 | pfleura2 | STACK( 2, STKPNT ) = J |
| 225 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 226 | 1 | pfleura2 | STACK( 1, STKPNT ) = J + 1 |
| 227 | 1 | pfleura2 | STACK( 2, STKPNT ) = ENDD |
| 228 | 1 | pfleura2 | ELSE |
| 229 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 230 | 1 | pfleura2 | STACK( 1, STKPNT ) = J + 1 |
| 231 | 1 | pfleura2 | STACK( 2, STKPNT ) = ENDD |
| 232 | 1 | pfleura2 | STKPNT = STKPNT + 1 |
| 233 | 1 | pfleura2 | STACK( 1, STKPNT ) = START |
| 234 | 1 | pfleura2 | STACK( 2, STKPNT ) = J |
| 235 | 1 | pfleura2 | END IF |
| 236 | 1 | pfleura2 | END IF |
| 237 | 1 | pfleura2 | END IF |
| 238 | 1 | pfleura2 | IF( STKPNT.GT.0 ) |
| 239 | 1 | pfleura2 | $ GO TO 10 |
| 240 | 1 | pfleura2 | RETURN |
| 241 | 1 | pfleura2 | * |
| 242 | 1 | pfleura2 | * End of DLASRT |
| 243 | 1 | pfleura2 | * |
| 244 | 1 | pfleura2 | END |