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1.4 bertrand 1: *> \brief \b DSYCONV
2: *
3: * =========== DOCUMENTATION ===========
4: *
5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
7: *
8: *> \htmlonly
9: *> Download DSYCONV + dependencies
10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dsyconv.f">
11: *> [TGZ]</a>
12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dsyconv.f">
13: *> [ZIP]</a>
14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dsyconv.f">
15: *> [TXT]</a>
16: *> \endhtmlonly
17: *
18: * Definition:
19: * ===========
20: *
21: * SUBROUTINE DSYCONV( UPLO, WAY, N, A, LDA, IPIV, WORK, INFO )
22: *
23: * .. Scalar Arguments ..
24: * CHARACTER UPLO, WAY
25: * INTEGER INFO, LDA, N
26: * ..
27: * .. Array Arguments ..
28: * INTEGER IPIV( * )
29: * DOUBLE PRECISION A( LDA, * ), WORK( * )
30: * ..
31: *
32: *
33: *> \par Purpose:
34: * =============
35: *>
36: *> \verbatim
37: *>
38: *> DSYCONV convert A given by TRF into L and D and vice-versa.
39: *> Get Non-diag elements of D (returned in workspace) and
40: *> apply or reverse permutation done in TRF.
41: *> \endverbatim
42: *
43: * Arguments:
44: * ==========
45: *
46: *> \param[in] UPLO
47: *> \verbatim
48: *> UPLO is CHARACTER*1
49: *> Specifies whether the details of the factorization are stored
50: *> as an upper or lower triangular matrix.
51: *> = 'U': Upper triangular, form is A = U*D*U**T;
52: *> = 'L': Lower triangular, form is A = L*D*L**T.
53: *> \endverbatim
54: *>
55: *> \param[in] WAY
56: *> \verbatim
57: *> WAY is CHARACTER*1
58: *> = 'C': Convert
59: *> = 'R': Revert
60: *> \endverbatim
61: *>
62: *> \param[in] N
63: *> \verbatim
64: *> N is INTEGER
65: *> The order of the matrix A. N >= 0.
66: *> \endverbatim
67: *>
68: *> \param[in] A
69: *> \verbatim
70: *> A is DOUBLE PRECISION array, dimension (LDA,N)
71: *> The block diagonal matrix D and the multipliers used to
72: *> obtain the factor U or L as computed by DSYTRF.
73: *> \endverbatim
74: *>
75: *> \param[in] LDA
76: *> \verbatim
77: *> LDA is INTEGER
78: *> The leading dimension of the array A. LDA >= max(1,N).
79: *> \endverbatim
80: *>
81: *> \param[in] IPIV
82: *> \verbatim
83: *> IPIV is INTEGER array, dimension (N)
84: *> Details of the interchanges and the block structure of D
85: *> as determined by DSYTRF.
86: *> \endverbatim
87: *>
88: *> \param[out] WORK
89: *> \verbatim
90: *> WORK is DOUBLE PRECISION array, dimension (N)
91: *> \endverbatim
92: *>
93: *> \param[out] INFO
94: *> \verbatim
95: *> INFO is INTEGER
96: *> = 0: successful exit
97: *> < 0: if INFO = -i, the i-th argument had an illegal value
98: *> \endverbatim
99: *
100: * Authors:
101: * ========
102: *
103: *> \author Univ. of Tennessee
104: *> \author Univ. of California Berkeley
105: *> \author Univ. of Colorado Denver
106: *> \author NAG Ltd.
107: *
108: *> \date November 2011
109: *
110: *> \ingroup doubleSYcomputational
111: *
112: * =====================================================================
1.1 bertrand 113: SUBROUTINE DSYCONV( UPLO, WAY, N, A, LDA, IPIV, WORK, INFO )
114: *
1.4 bertrand 115: * -- LAPACK computational routine (version 3.4.0) --
1.1 bertrand 116: * -- LAPACK is a software package provided by Univ. of Tennessee, --
117: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.4 bertrand 118: * November 2011
1.1 bertrand 119: *
120: * .. Scalar Arguments ..
121: CHARACTER UPLO, WAY
122: INTEGER INFO, LDA, N
123: * ..
124: * .. Array Arguments ..
125: INTEGER IPIV( * )
126: DOUBLE PRECISION A( LDA, * ), WORK( * )
127: * ..
128: *
129: * =====================================================================
130: *
131: * .. Parameters ..
132: DOUBLE PRECISION ZERO
133: PARAMETER ( ZERO = 0.0D+0 )
134: * ..
135: * .. External Functions ..
136: LOGICAL LSAME
137: EXTERNAL LSAME
138: *
139: * .. External Subroutines ..
140: EXTERNAL XERBLA
141: * .. Local Scalars ..
142: LOGICAL UPPER, CONVERT
143: INTEGER I, IP, J
144: DOUBLE PRECISION TEMP
145: * ..
146: * .. Executable Statements ..
147: *
148: INFO = 0
149: UPPER = LSAME( UPLO, 'U' )
150: CONVERT = LSAME( WAY, 'C' )
151: IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
152: INFO = -1
153: ELSE IF( .NOT.CONVERT .AND. .NOT.LSAME( WAY, 'R' ) ) THEN
154: INFO = -2
155: ELSE IF( N.LT.0 ) THEN
156: INFO = -3
157: ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
158: INFO = -5
159:
160: END IF
161: IF( INFO.NE.0 ) THEN
162: CALL XERBLA( 'DSYCONV', -INFO )
163: RETURN
164: END IF
165: *
166: * Quick return if possible
167: *
168: IF( N.EQ.0 )
169: $ RETURN
170: *
171: IF( UPPER ) THEN
172: *
173: * A is UPPER
174: *
175: * Convert A (A is upper)
176: *
177: * Convert VALUE
178: *
179: IF ( CONVERT ) THEN
180: I=N
181: WORK(1)=ZERO
182: DO WHILE ( I .GT. 1 )
183: IF( IPIV(I) .LT. 0 ) THEN
184: WORK(I)=A(I-1,I)
185: A(I-1,I)=ZERO
186: I=I-1
187: ELSE
188: WORK(I)=ZERO
189: ENDIF
190: I=I-1
191: END DO
192: *
193: * Convert PERMUTATIONS
194: *
195: I=N
196: DO WHILE ( I .GE. 1 )
197: IF( IPIV(I) .GT. 0) THEN
198: IP=IPIV(I)
199: IF( I .LT. N) THEN
200: DO 12 J= I+1,N
201: TEMP=A(IP,J)
202: A(IP,J)=A(I,J)
203: A(I,J)=TEMP
204: 12 CONTINUE
205: ENDIF
206: ELSE
207: IP=-IPIV(I)
208: IF( I .LT. N) THEN
209: DO 13 J= I+1,N
210: TEMP=A(IP,J)
211: A(IP,J)=A(I-1,J)
212: A(I-1,J)=TEMP
213: 13 CONTINUE
214: ENDIF
215: I=I-1
216: ENDIF
217: I=I-1
218: END DO
219:
220: ELSE
221: *
222: * Revert A (A is upper)
223: *
224: *
225: * Revert PERMUTATIONS
226: *
227: I=1
228: DO WHILE ( I .LE. N )
229: IF( IPIV(I) .GT. 0 ) THEN
230: IP=IPIV(I)
231: IF( I .LT. N) THEN
232: DO J= I+1,N
233: TEMP=A(IP,J)
234: A(IP,J)=A(I,J)
235: A(I,J)=TEMP
236: END DO
237: ENDIF
238: ELSE
239: IP=-IPIV(I)
240: I=I+1
241: IF( I .LT. N) THEN
242: DO J= I+1,N
243: TEMP=A(IP,J)
244: A(IP,J)=A(I-1,J)
245: A(I-1,J)=TEMP
246: END DO
247: ENDIF
248: ENDIF
249: I=I+1
250: END DO
251: *
252: * Revert VALUE
253: *
254: I=N
255: DO WHILE ( I .GT. 1 )
256: IF( IPIV(I) .LT. 0 ) THEN
257: A(I-1,I)=WORK(I)
258: I=I-1
259: ENDIF
260: I=I-1
261: END DO
262: END IF
263: ELSE
264: *
265: * A is LOWER
266: *
267: IF ( CONVERT ) THEN
268: *
269: * Convert A (A is lower)
270: *
271: *
272: * Convert VALUE
273: *
274: I=1
275: WORK(N)=ZERO
276: DO WHILE ( I .LE. N )
277: IF( I.LT.N .AND. IPIV(I) .LT. 0 ) THEN
278: WORK(I)=A(I+1,I)
279: A(I+1,I)=ZERO
280: I=I+1
281: ELSE
282: WORK(I)=ZERO
283: ENDIF
284: I=I+1
285: END DO
286: *
287: * Convert PERMUTATIONS
288: *
289: I=1
290: DO WHILE ( I .LE. N )
291: IF( IPIV(I) .GT. 0 ) THEN
292: IP=IPIV(I)
293: IF (I .GT. 1) THEN
294: DO 22 J= 1,I-1
295: TEMP=A(IP,J)
296: A(IP,J)=A(I,J)
297: A(I,J)=TEMP
298: 22 CONTINUE
299: ENDIF
300: ELSE
301: IP=-IPIV(I)
302: IF (I .GT. 1) THEN
303: DO 23 J= 1,I-1
304: TEMP=A(IP,J)
305: A(IP,J)=A(I+1,J)
306: A(I+1,J)=TEMP
307: 23 CONTINUE
308: ENDIF
309: I=I+1
310: ENDIF
311: I=I+1
312: END DO
313: ELSE
314: *
315: * Revert A (A is lower)
316: *
317: *
318: * Revert PERMUTATIONS
319: *
320: I=N
321: DO WHILE ( I .GE. 1 )
322: IF( IPIV(I) .GT. 0 ) THEN
323: IP=IPIV(I)
324: IF (I .GT. 1) THEN
325: DO J= 1,I-1
326: TEMP=A(I,J)
327: A(I,J)=A(IP,J)
328: A(IP,J)=TEMP
329: END DO
330: ENDIF
331: ELSE
332: IP=-IPIV(I)
333: I=I-1
334: IF (I .GT. 1) THEN
335: DO J= 1,I-1
336: TEMP=A(I+1,J)
337: A(I+1,J)=A(IP,J)
338: A(IP,J)=TEMP
339: END DO
340: ENDIF
341: ENDIF
342: I=I-1
343: END DO
344: *
345: * Revert VALUE
346: *
347: I=1
348: DO WHILE ( I .LE. N-1 )
349: IF( IPIV(I) .LT. ZERO ) THEN
350: A(I+1,I)=WORK(I)
351: I=I+1
352: ENDIF
353: I=I+1
354: END DO
355: END IF
356: END IF
357:
358: RETURN
359: *
360: * End of DSYCONV
361: *
362: END