SCALAPACK 2.2.2
LAPACK: Linear Algebra PACKage
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◆ pbsmatadd()

subroutine pbsmatadd ( integer  icontxt,
character*1  mode,
integer  m,
integer  n,
real  alpha,
real, dimension( lda, * )  a,
integer  lda,
real  beta,
real, dimension( ldb, * )  b,
integer  ldb 
)

Definition at line 1 of file pbsmatadd.f.

3*
4* -- PB-BLAS routine (version 2.1) --
5* University of Tennessee, Knoxville, Oak Ridge National Laboratory.
6* April 28, 1996
7*
8* .. Scalar Arguments ..
9 CHARACTER*1 MODE
10 INTEGER ICONTXT, LDA, LDB, M, N
11 REAL ALPHA, BETA
12* ..
13* .. Array Arguments ..
14 REAL A( LDA, * ), B( LDB, * )
15* ..
16*
17* Purpose
18* =======
19*
20* PBSMATADD performs the matrix add operation B := alpha*A + beta*B,
21* where alpha and beta are scalars, and A and B are m-by-n
22* upper/lower trapezoidal matrices, or rectangular matrices.
23*
24* Arguments
25* =========
26*
27* ICONTXT (input) INTEGER
28* ICONTXT is the BLACS mechanism for partitioning communication
29* space. A defining property of a context is that a message in
30* a context cannot be sent or received in another context. The
31* BLACS context includes the definition of a grid, and each
32* process' coordinates in it.
33*
34* MODE (input) CHARACTER*1
35* Specifies the part of the matrix A, or (conjugate) transposed
36* matrix A to be added to the matrix B,
37* = 'U': Upper triangular part
38* up(B) = alpha*up(A) + beta*up(B)
39* = 'L': Lower triangular part
40* lo(B) = alpha*lo(A) + beta*lo(B)
41* = 'T': Transposed matrix A
42* B = alpha*A**T + beta*B
43* = 'C': Conjugate transposed matrix A
44* B = alpha*A**H + beta*B
45* Otherwise: B = alpha*A + beta*B
46* if M = LDA = LDB: use one BLAS loop
47* if MODE = 'V' : columnwise copy using BLAS if possible
48* else : use double loops
49*
50* M (input) INTEGER
51* M specifies the number of columns of the matrix A if
52* MODE != 'T'/'C', and it specifies the number of rows of the
53* matrix A otherwise. It also specifies the number of rows of
54* the matrix B. M >= 0.
55*
56* N (input) INTEGER
57* N specifies the number of rows of the matrix A if
58* MODE != 'T'/'C', and it specifies the number of columns of
59* the matrix A otherwise. It also specifies the number of
60* columns of the matrix B. N >= 0.
61*
62* ALPHA (input) REAL
63* ALPHA specifies the scalar alpha.
64*
65* A (input) REAL array, dimension (LDA,N)
66* The m by n matrix A if MODE != 'T'/'C'.
67* If MODE = 'U', only the upper triangle or trapezoid is
68* accessed; if MODE = 'L', only the lower triangle or
69* trapezoid is accessed. Otherwise all m-by-n data matrix
70* is accessed.
71* And the n by m matrix A if MODE = 'T'/'C'.
72*
73* LDA (input) INTEGER
74* The leading dimension of the array A. LDA >= max(1,M) if
75* MODE != 'T'/'C'. And LDA >= max(1,N) if MODE = 'T'/'C'.
76*
77* BETA (input) REAL
78* BETA specifies the scalar beta.
79*
80* B (input) REAL array, dimension (LDB,N)
81* On exit, B = alpha*A + beta*B
82*
83* LDB (input) INTEGER
84* The leading dimension of the array B. LDB >= max(1,M).
85*
86* =====================================================================
87*
88* .. Parameters ..
89 REAL ZERO, ONE
90 parameter( zero = 0.0e+0, one = 1.0e+0)
91* ..
92* .. Local Scalars ..
93 INTEGER I, J
94* ..
95* .. External Functions ..
96 LOGICAL LSAME
97 EXTERNAL lsame
98* ..
99* .. External Subroutines ..
100 EXTERNAL sscal, scopy, saxpy
101* ..
102* .. Intrinsic Functions ..
103 INTRINSIC min
104* ..
105* .. Executable Statements ..
106*
107 IF( m.LE.0 .OR. n.LE.0 .OR. ( alpha.EQ.zero.AND.beta.EQ.one ) )
108 $ RETURN
109*
110* A is upper triangular or upper trapezoidal,
111*
112 IF( lsame( mode, 'U' ) ) THEN
113 IF( alpha.EQ.zero ) THEN
114 IF( beta.EQ.zero ) THEN
115 DO 20 j = 1, n
116 DO 10 i = 1, min( j, m )
117 b( i, j ) = zero
118 10 CONTINUE
119 20 CONTINUE
120 ELSE
121 DO 40 j = 1, n
122 DO 30 i = 1, min( j, m )
123 b( i, j ) = beta * b( i, j )
124 30 CONTINUE
125 40 CONTINUE
126 END IF
127*
128 ELSE IF( alpha.EQ.one ) THEN
129 IF( beta.EQ.zero ) THEN
130 DO 60 j = 1, n
131 DO 50 i = 1, min( j, m )
132 b( i, j ) = a( i, j )
133 50 CONTINUE
134 60 CONTINUE
135 ELSE IF( beta.EQ.one ) THEN
136 DO 80 j = 1, n
137 DO 70 i = 1, min( j, m )
138 b( i, j ) = a( i, j ) + b( i, j )
139 70 CONTINUE
140 80 CONTINUE
141 ELSE
142 DO 100 j = 1, n
143 DO 90 i = 1, min( j, m )
144 b( i, j ) = a( i, j ) + beta * b( i, j )
145 90 CONTINUE
146 100 CONTINUE
147 END IF
148*
149 ELSE
150 IF( beta.EQ.zero ) THEN
151 DO 120 j = 1, n
152 DO 110 i = 1, min( j, m )
153 b( i, j ) = alpha * a( i, j )
154 110 CONTINUE
155 120 CONTINUE
156 ELSE IF( beta.EQ.one ) THEN
157 DO 140 j = 1, n
158 DO 130 i = 1, min( j, m )
159 b( i, j ) = alpha * a( i, j ) + b( i, j )
160 130 CONTINUE
161 140 CONTINUE
162 ELSE
163 DO 160 j = 1, n
164 DO 150 i = 1, min( j, m )
165 b( i, j ) = alpha * a( i, j ) + beta * b( i, j )
166 150 CONTINUE
167 160 CONTINUE
168 END IF
169 END IF
170*
171* A is lower triangular or upper trapezoidal,
172*
173 ELSE IF( lsame( mode, 'L' ) ) THEN
174 IF( alpha.EQ.zero ) THEN
175 IF( beta.EQ.zero ) THEN
176 DO 180 j = 1, n
177 DO 170 i = j, m
178 b( i, j ) = zero
179 170 CONTINUE
180 180 CONTINUE
181 ELSE
182 DO 200 j = 1, n
183 DO 190 i = j, m
184 b( i, j ) = beta * b( i, j )
185 190 CONTINUE
186 200 CONTINUE
187 END IF
188*
189 ELSE IF( alpha.EQ.one ) THEN
190 IF( beta.EQ.zero ) THEN
191 DO 220 j = 1, n
192 DO 210 i = j, m
193 b( i, j ) = a( i, j )
194 210 CONTINUE
195 220 CONTINUE
196 ELSE IF( beta.EQ.one ) THEN
197 DO 240 j = 1, n
198 DO 230 i = j, m
199 b( i, j ) = a( i, j ) + b( i, j )
200 230 CONTINUE
201 240 CONTINUE
202 ELSE
203 DO 260 j = 1, n
204 DO 250 i = j, m
205 b( i, j ) = a( i, j ) + beta * b( i, j )
206 250 CONTINUE
207 260 CONTINUE
208 END IF
209*
210 ELSE
211 IF( beta.EQ.zero ) THEN
212 DO 280 j = 1, n
213 DO 270 i = j, m
214 b( i, j ) = alpha * a( i, j )
215 270 CONTINUE
216 280 CONTINUE
217 ELSE IF( beta.EQ.one ) THEN
218 DO 300 j = 1, n
219 DO 290 i = j, m
220 b( i, j ) = alpha * a( i, j ) + b( i, j )
221 290 CONTINUE
222 300 CONTINUE
223 ELSE
224 DO 320 j = 1, n
225 DO 310 i = j, m
226 b( i, j ) = alpha * a( i, j ) + beta * b( i, j )
227 310 CONTINUE
228 320 CONTINUE
229 END IF
230 END IF
231*
232* If MODE = 'Transpose'/'Conjugate'
233*
234 ELSE IF( lsame( mode, 'T' ) .OR. lsame( mode, 'C' ) ) THEN
235 IF( alpha.EQ.zero ) THEN
236 IF( beta.EQ.zero ) THEN
237 DO 340 j = 1, n
238 DO 330 i = 1, m
239 b( i, j ) = zero
240 330 CONTINUE
241 340 CONTINUE
242 ELSE
243 DO 360 j = 1, n
244 DO 350 i = 1, m
245 b( i, j ) = beta * b( i, j )
246 350 CONTINUE
247 360 CONTINUE
248 END IF
249*
250 ELSE IF( alpha.EQ.one ) THEN
251 IF( beta.EQ.zero ) THEN
252 DO 380 j = 1, n
253 DO 370 i = 1, m
254 b( i, j ) = a( j, i )
255 370 CONTINUE
256 380 CONTINUE
257 ELSE IF( beta.EQ.one ) THEN
258 DO 400 j = 1, n
259 DO 390 i = 1, m
260 b( i, j ) = a( j, i ) + b( i, j )
261 390 CONTINUE
262 400 CONTINUE
263 ELSE
264 DO 420 j = 1, n
265 DO 410 i = 1, m
266 b( i, j ) = a( j, i ) + beta * b( i, j )
267 410 CONTINUE
268 420 CONTINUE
269 END IF
270*
271 ELSE
272 IF( beta.EQ.zero ) THEN
273 DO 440 j = 1, n
274 DO 430 i = 1, m
275 b( i, j ) = alpha * a( j, i )
276 430 CONTINUE
277 440 CONTINUE
278 ELSE IF( beta.EQ.one ) THEN
279 DO 460 j = 1, n
280 DO 450 i = 1, m
281 b( i, j ) = alpha * a( j, i ) + b( i, j )
282 450 CONTINUE
283 460 CONTINUE
284 ELSE
285 DO 480 j = 1, n
286 DO 470 i = 1, m
287 b( i, j ) = alpha * a( j, i ) + beta * b( i, j )
288 470 CONTINUE
289 480 CONTINUE
290 END IF
291 END IF
292*
293* Other cases (for genral matrix additions)
294*
295 ELSE
296 IF( alpha.EQ.zero ) THEN
297 IF( beta.EQ.zero ) THEN
298 DO 500 j = 1, n
299 DO 490 i = 1, m
300 b( i, j ) = zero
301 490 CONTINUE
302 500 CONTINUE
303*
304 ELSE
305 IF( m.EQ.ldb ) THEN
306 CALL sscal( m*n, beta, b( 1, 1 ), 1 )
307 ELSE IF( lsame( mode, 'V' ) ) THEN
308 DO 510 j = 1, n
309 CALL sscal( m, beta, b( 1, j ), 1 )
310 510 CONTINUE
311 ELSE
312 DO 530 j = 1, n
313 DO 520 i = 1, m
314 b( i, j ) = beta * b( i, j )
315 520 CONTINUE
316 530 CONTINUE
317 END IF
318 END IF
319*
320 ELSE IF( alpha.EQ.one ) THEN
321 IF( beta.EQ.zero ) THEN
322 IF( m.EQ.lda .AND. m.EQ.ldb ) THEN
323 CALL scopy( m*n, a( 1, 1 ), 1, b( 1, 1 ), 1 )
324 ELSE IF( lsame( mode, 'V' ) ) THEN
325 DO 540 j = 1, n
326 CALL scopy( m, a( 1, j ), 1, b( 1, j ), 1 )
327 540 CONTINUE
328 ELSE
329 DO 560 j = 1, n
330 DO 550 i = 1, m
331 b( i, j ) = a( i, j )
332 550 CONTINUE
333 560 CONTINUE
334 END IF
335*
336 ELSE IF( beta.EQ.one ) THEN
337 DO 580 j = 1, n
338 DO 570 i = 1, m
339 b( i, j ) = a( i, j ) + b( i, j )
340 570 CONTINUE
341 580 CONTINUE
342*
343 ELSE
344 DO 600 j = 1, n
345 DO 590 i = 1, m
346 b( i, j ) = a( i, j ) + beta * b( i, j )
347 590 CONTINUE
348 600 CONTINUE
349 END IF
350*
351 ELSE
352 IF( beta.EQ.zero ) THEN
353 DO 620 j = 1, n
354 DO 610 i = 1, m
355 b( i, j ) = alpha * a( i, j )
356 610 CONTINUE
357 620 CONTINUE
358*
359 ELSE IF( beta.EQ.one ) THEN
360 IF( m.EQ.lda .AND. m.EQ.ldb ) THEN
361 CALL saxpy( m*n, alpha, a( 1, 1 ), 1, b( 1, 1 ), 1 )
362 ELSE IF( lsame( mode, 'V' ) ) THEN
363 DO 630 j = 1, n
364 CALL saxpy( m, alpha, a( 1, j ), 1, b( 1, j ), 1 )
365 630 CONTINUE
366 ELSE
367 DO 650 j = 1, n
368 DO 640 i = 1, m
369 b( i, j ) = alpha * a( i, j ) + b( i, j )
370 640 CONTINUE
371 650 CONTINUE
372 END IF
373*
374 ELSE
375 DO 670 j = 1, n
376 DO 660 i = 1, m
377 b( i, j ) = alpha * a( i, j ) + beta * b( i, j )
378 660 CONTINUE
379 670 CONTINUE
380 END IF
381 END IF
382 END IF
383*
384 RETURN
385*
386* End of PBSMATADD
387*
min
#define min(A, B)
Definition pcgemr.c:181
lsame
logical function lsame(ca, cb)
Definition tools.f:1724
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