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1.8 bertrand 1: *> \brief \b ZTRMM
1.1 bertrand 2: *
1.8 bertrand 3: * =========== DOCUMENTATION ===========
1.1 bertrand 4: *
1.8 bertrand 5: * Online html documentation available at
6: * http://www.netlib.org/lapack/explore-html/
1.1 bertrand 7: *
1.8 bertrand 8: * Definition:
9: * ===========
10: *
11: * SUBROUTINE ZTRMM(SIDE,UPLO,TRANSA,DIAG,M,N,ALPHA,A,LDA,B,LDB)
12: *
13: * .. Scalar Arguments ..
14: * COMPLEX*16 ALPHA
15: * INTEGER LDA,LDB,M,N
16: * CHARACTER DIAG,SIDE,TRANSA,UPLO
17: * ..
18: * .. Array Arguments ..
19: * COMPLEX*16 A(LDA,*),B(LDB,*)
20: * ..
21: *
22: *
23: *> \par Purpose:
24: * =============
25: *>
26: *> \verbatim
27: *>
28: *> ZTRMM performs one of the matrix-matrix operations
29: *>
30: *> B := alpha*op( A )*B, or B := alpha*B*op( A )
31: *>
32: *> where alpha is a scalar, B is an m by n matrix, A is a unit, or
33: *> non-unit, upper or lower triangular matrix and op( A ) is one of
34: *>
35: *> op( A ) = A or op( A ) = A**T or op( A ) = A**H.
36: *> \endverbatim
1.1 bertrand 37: *
1.8 bertrand 38: * Arguments:
1.1 bertrand 39: * ==========
40: *
1.8 bertrand 41: *> \param[in] SIDE
42: *> \verbatim
43: *> SIDE is CHARACTER*1
44: *> On entry, SIDE specifies whether op( A ) multiplies B from
45: *> the left or right as follows:
46: *>
47: *> SIDE = 'L' or 'l' B := alpha*op( A )*B.
48: *>
49: *> SIDE = 'R' or 'r' B := alpha*B*op( A ).
50: *> \endverbatim
51: *>
52: *> \param[in] UPLO
53: *> \verbatim
54: *> UPLO is CHARACTER*1
55: *> On entry, UPLO specifies whether the matrix A is an upper or
56: *> lower triangular matrix as follows:
57: *>
58: *> UPLO = 'U' or 'u' A is an upper triangular matrix.
59: *>
60: *> UPLO = 'L' or 'l' A is a lower triangular matrix.
61: *> \endverbatim
62: *>
63: *> \param[in] TRANSA
64: *> \verbatim
65: *> TRANSA is CHARACTER*1
66: *> On entry, TRANSA specifies the form of op( A ) to be used in
67: *> the matrix multiplication as follows:
68: *>
69: *> TRANSA = 'N' or 'n' op( A ) = A.
70: *>
71: *> TRANSA = 'T' or 't' op( A ) = A**T.
72: *>
73: *> TRANSA = 'C' or 'c' op( A ) = A**H.
74: *> \endverbatim
75: *>
76: *> \param[in] DIAG
77: *> \verbatim
78: *> DIAG is CHARACTER*1
79: *> On entry, DIAG specifies whether or not A is unit triangular
80: *> as follows:
81: *>
82: *> DIAG = 'U' or 'u' A is assumed to be unit triangular.
83: *>
84: *> DIAG = 'N' or 'n' A is not assumed to be unit
85: *> triangular.
86: *> \endverbatim
87: *>
88: *> \param[in] M
89: *> \verbatim
90: *> M is INTEGER
91: *> On entry, M specifies the number of rows of B. M must be at
92: *> least zero.
93: *> \endverbatim
94: *>
95: *> \param[in] N
96: *> \verbatim
97: *> N is INTEGER
98: *> On entry, N specifies the number of columns of B. N must be
99: *> at least zero.
100: *> \endverbatim
101: *>
102: *> \param[in] ALPHA
103: *> \verbatim
104: *> ALPHA is COMPLEX*16
105: *> On entry, ALPHA specifies the scalar alpha. When alpha is
106: *> zero then A is not referenced and B need not be set before
107: *> entry.
108: *> \endverbatim
109: *>
110: *> \param[in] A
111: *> \verbatim
112: *> A is COMPLEX*16 array of DIMENSION ( LDA, k ), where k is m
113: *> when SIDE = 'L' or 'l' and is n when SIDE = 'R' or 'r'.
114: *> Before entry with UPLO = 'U' or 'u', the leading k by k
115: *> upper triangular part of the array A must contain the upper
116: *> triangular matrix and the strictly lower triangular part of
117: *> A is not referenced.
118: *> Before entry with UPLO = 'L' or 'l', the leading k by k
119: *> lower triangular part of the array A must contain the lower
120: *> triangular matrix and the strictly upper triangular part of
121: *> A is not referenced.
122: *> Note that when DIAG = 'U' or 'u', the diagonal elements of
123: *> A are not referenced either, but are assumed to be unity.
124: *> \endverbatim
125: *>
126: *> \param[in] LDA
127: *> \verbatim
128: *> LDA is INTEGER
129: *> On entry, LDA specifies the first dimension of A as declared
130: *> in the calling (sub) program. When SIDE = 'L' or 'l' then
131: *> LDA must be at least max( 1, m ), when SIDE = 'R' or 'r'
132: *> then LDA must be at least max( 1, n ).
133: *> \endverbatim
134: *>
135: *> \param[in] B
136: *> \verbatim
137: *> B is (input/output) COMPLEX*16 array of DIMENSION ( LDB, n ).
138: *> Before entry, the leading m by n part of the array B must
139: *> contain the matrix B, and on exit is overwritten by the
140: *> transformed matrix.
141: *> \endverbatim
142: *>
143: *> \param[in] LDB
144: *> \verbatim
145: *> LDB is INTEGER
146: *> On entry, LDB specifies the first dimension of B as declared
147: *> in the calling (sub) program. LDB must be at least
148: *> max( 1, m ).
149: *> \endverbatim
150: *
151: * Authors:
152: * ========
153: *
154: *> \author Univ. of Tennessee
155: *> \author Univ. of California Berkeley
156: *> \author Univ. of Colorado Denver
157: *> \author NAG Ltd.
158: *
159: *> \date November 2011
160: *
161: *> \ingroup complex16_blas_level3
162: *
163: *> \par Further Details:
164: * =====================
165: *>
166: *> \verbatim
167: *>
168: *> Level 3 Blas routine.
169: *>
170: *> -- Written on 8-February-1989.
171: *> Jack Dongarra, Argonne National Laboratory.
172: *> Iain Duff, AERE Harwell.
173: *> Jeremy Du Croz, Numerical Algorithms Group Ltd.
174: *> Sven Hammarling, Numerical Algorithms Group Ltd.
175: *> \endverbatim
176: *>
177: * =====================================================================
178: SUBROUTINE ZTRMM(SIDE,UPLO,TRANSA,DIAG,M,N,ALPHA,A,LDA,B,LDB)
1.1 bertrand 179: *
1.8 bertrand 180: * -- Reference BLAS level3 routine (version 3.4.0) --
181: * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
182: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
183: * November 2011
1.1 bertrand 184: *
1.8 bertrand 185: * .. Scalar Arguments ..
186: COMPLEX*16 ALPHA
187: INTEGER LDA,LDB,M,N
188: CHARACTER DIAG,SIDE,TRANSA,UPLO
189: * ..
190: * .. Array Arguments ..
191: COMPLEX*16 A(LDA,*),B(LDB,*)
192: * ..
1.1 bertrand 193: *
194: * =====================================================================
195: *
196: * .. External Functions ..
197: LOGICAL LSAME
198: EXTERNAL LSAME
199: * ..
200: * .. External Subroutines ..
201: EXTERNAL XERBLA
202: * ..
203: * .. Intrinsic Functions ..
204: INTRINSIC DCONJG,MAX
205: * ..
206: * .. Local Scalars ..
1.8 bertrand 207: COMPLEX*16 TEMP
1.1 bertrand 208: INTEGER I,INFO,J,K,NROWA
209: LOGICAL LSIDE,NOCONJ,NOUNIT,UPPER
210: * ..
211: * .. Parameters ..
1.8 bertrand 212: COMPLEX*16 ONE
1.1 bertrand 213: PARAMETER (ONE= (1.0D+0,0.0D+0))
1.8 bertrand 214: COMPLEX*16 ZERO
1.1 bertrand 215: PARAMETER (ZERO= (0.0D+0,0.0D+0))
216: * ..
217: *
218: * Test the input parameters.
219: *
220: LSIDE = LSAME(SIDE,'L')
221: IF (LSIDE) THEN
222: NROWA = M
223: ELSE
224: NROWA = N
225: END IF
226: NOCONJ = LSAME(TRANSA,'T')
227: NOUNIT = LSAME(DIAG,'N')
228: UPPER = LSAME(UPLO,'U')
229: *
230: INFO = 0
231: IF ((.NOT.LSIDE) .AND. (.NOT.LSAME(SIDE,'R'))) THEN
232: INFO = 1
233: ELSE IF ((.NOT.UPPER) .AND. (.NOT.LSAME(UPLO,'L'))) THEN
234: INFO = 2
235: ELSE IF ((.NOT.LSAME(TRANSA,'N')) .AND.
236: + (.NOT.LSAME(TRANSA,'T')) .AND.
237: + (.NOT.LSAME(TRANSA,'C'))) THEN
238: INFO = 3
239: ELSE IF ((.NOT.LSAME(DIAG,'U')) .AND. (.NOT.LSAME(DIAG,'N'))) THEN
240: INFO = 4
241: ELSE IF (M.LT.0) THEN
242: INFO = 5
243: ELSE IF (N.LT.0) THEN
244: INFO = 6
245: ELSE IF (LDA.LT.MAX(1,NROWA)) THEN
246: INFO = 9
247: ELSE IF (LDB.LT.MAX(1,M)) THEN
248: INFO = 11
249: END IF
250: IF (INFO.NE.0) THEN
251: CALL XERBLA('ZTRMM ',INFO)
252: RETURN
253: END IF
254: *
255: * Quick return if possible.
256: *
257: IF (M.EQ.0 .OR. N.EQ.0) RETURN
258: *
259: * And when alpha.eq.zero.
260: *
261: IF (ALPHA.EQ.ZERO) THEN
262: DO 20 J = 1,N
263: DO 10 I = 1,M
264: B(I,J) = ZERO
265: 10 CONTINUE
266: 20 CONTINUE
267: RETURN
268: END IF
269: *
270: * Start the operations.
271: *
272: IF (LSIDE) THEN
273: IF (LSAME(TRANSA,'N')) THEN
274: *
275: * Form B := alpha*A*B.
276: *
277: IF (UPPER) THEN
278: DO 50 J = 1,N
279: DO 40 K = 1,M
280: IF (B(K,J).NE.ZERO) THEN
281: TEMP = ALPHA*B(K,J)
282: DO 30 I = 1,K - 1
283: B(I,J) = B(I,J) + TEMP*A(I,K)
284: 30 CONTINUE
285: IF (NOUNIT) TEMP = TEMP*A(K,K)
286: B(K,J) = TEMP
287: END IF
288: 40 CONTINUE
289: 50 CONTINUE
290: ELSE
291: DO 80 J = 1,N
292: DO 70 K = M,1,-1
293: IF (B(K,J).NE.ZERO) THEN
294: TEMP = ALPHA*B(K,J)
295: B(K,J) = TEMP
296: IF (NOUNIT) B(K,J) = B(K,J)*A(K,K)
297: DO 60 I = K + 1,M
298: B(I,J) = B(I,J) + TEMP*A(I,K)
299: 60 CONTINUE
300: END IF
301: 70 CONTINUE
302: 80 CONTINUE
303: END IF
304: ELSE
305: *
1.7 bertrand 306: * Form B := alpha*A**T*B or B := alpha*A**H*B.
1.1 bertrand 307: *
308: IF (UPPER) THEN
309: DO 120 J = 1,N
310: DO 110 I = M,1,-1
311: TEMP = B(I,J)
312: IF (NOCONJ) THEN
313: IF (NOUNIT) TEMP = TEMP*A(I,I)
314: DO 90 K = 1,I - 1
315: TEMP = TEMP + A(K,I)*B(K,J)
316: 90 CONTINUE
317: ELSE
318: IF (NOUNIT) TEMP = TEMP*DCONJG(A(I,I))
319: DO 100 K = 1,I - 1
320: TEMP = TEMP + DCONJG(A(K,I))*B(K,J)
321: 100 CONTINUE
322: END IF
323: B(I,J) = ALPHA*TEMP
324: 110 CONTINUE
325: 120 CONTINUE
326: ELSE
327: DO 160 J = 1,N
328: DO 150 I = 1,M
329: TEMP = B(I,J)
330: IF (NOCONJ) THEN
331: IF (NOUNIT) TEMP = TEMP*A(I,I)
332: DO 130 K = I + 1,M
333: TEMP = TEMP + A(K,I)*B(K,J)
334: 130 CONTINUE
335: ELSE
336: IF (NOUNIT) TEMP = TEMP*DCONJG(A(I,I))
337: DO 140 K = I + 1,M
338: TEMP = TEMP + DCONJG(A(K,I))*B(K,J)
339: 140 CONTINUE
340: END IF
341: B(I,J) = ALPHA*TEMP
342: 150 CONTINUE
343: 160 CONTINUE
344: END IF
345: END IF
346: ELSE
347: IF (LSAME(TRANSA,'N')) THEN
348: *
349: * Form B := alpha*B*A.
350: *
351: IF (UPPER) THEN
352: DO 200 J = N,1,-1
353: TEMP = ALPHA
354: IF (NOUNIT) TEMP = TEMP*A(J,J)
355: DO 170 I = 1,M
356: B(I,J) = TEMP*B(I,J)
357: 170 CONTINUE
358: DO 190 K = 1,J - 1
359: IF (A(K,J).NE.ZERO) THEN
360: TEMP = ALPHA*A(K,J)
361: DO 180 I = 1,M
362: B(I,J) = B(I,J) + TEMP*B(I,K)
363: 180 CONTINUE
364: END IF
365: 190 CONTINUE
366: 200 CONTINUE
367: ELSE
368: DO 240 J = 1,N
369: TEMP = ALPHA
370: IF (NOUNIT) TEMP = TEMP*A(J,J)
371: DO 210 I = 1,M
372: B(I,J) = TEMP*B(I,J)
373: 210 CONTINUE
374: DO 230 K = J + 1,N
375: IF (A(K,J).NE.ZERO) THEN
376: TEMP = ALPHA*A(K,J)
377: DO 220 I = 1,M
378: B(I,J) = B(I,J) + TEMP*B(I,K)
379: 220 CONTINUE
380: END IF
381: 230 CONTINUE
382: 240 CONTINUE
383: END IF
384: ELSE
385: *
1.7 bertrand 386: * Form B := alpha*B*A**T or B := alpha*B*A**H.
1.1 bertrand 387: *
388: IF (UPPER) THEN
389: DO 280 K = 1,N
390: DO 260 J = 1,K - 1
391: IF (A(J,K).NE.ZERO) THEN
392: IF (NOCONJ) THEN
393: TEMP = ALPHA*A(J,K)
394: ELSE
395: TEMP = ALPHA*DCONJG(A(J,K))
396: END IF
397: DO 250 I = 1,M
398: B(I,J) = B(I,J) + TEMP*B(I,K)
399: 250 CONTINUE
400: END IF
401: 260 CONTINUE
402: TEMP = ALPHA
403: IF (NOUNIT) THEN
404: IF (NOCONJ) THEN
405: TEMP = TEMP*A(K,K)
406: ELSE
407: TEMP = TEMP*DCONJG(A(K,K))
408: END IF
409: END IF
410: IF (TEMP.NE.ONE) THEN
411: DO 270 I = 1,M
412: B(I,K) = TEMP*B(I,K)
413: 270 CONTINUE
414: END IF
415: 280 CONTINUE
416: ELSE
417: DO 320 K = N,1,-1
418: DO 300 J = K + 1,N
419: IF (A(J,K).NE.ZERO) THEN
420: IF (NOCONJ) THEN
421: TEMP = ALPHA*A(J,K)
422: ELSE
423: TEMP = ALPHA*DCONJG(A(J,K))
424: END IF
425: DO 290 I = 1,M
426: B(I,J) = B(I,J) + TEMP*B(I,K)
427: 290 CONTINUE
428: END IF
429: 300 CONTINUE
430: TEMP = ALPHA
431: IF (NOUNIT) THEN
432: IF (NOCONJ) THEN
433: TEMP = TEMP*A(K,K)
434: ELSE
435: TEMP = TEMP*DCONJG(A(K,K))
436: END IF
437: END IF
438: IF (TEMP.NE.ONE) THEN
439: DO 310 I = 1,M
440: B(I,K) = TEMP*B(I,K)
441: 310 CONTINUE
442: END IF
443: 320 CONTINUE
444: END IF
445: END IF
446: END IF
447: *
448: RETURN
449: *
450: * End of ZTRMM .
451: *
452: END