ScaLAPACK 2.1  2.1 ScaLAPACK: Scalable Linear Algebra PACKage
PB_Ctop.c
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1 /* ---------------------------------------------------------------------
2 *
3 * -- PBLAS auxiliary routine (version 2.0) --
4 * University of Tennessee, Knoxville, Oak Ridge National Laboratory,
5 * and University of California, Berkeley.
6 * April 1, 1998
7 *
8 * ---------------------------------------------------------------------
9 */
10 /*
11 * Include files
12 */
13 #include "../pblas.h"
14 #include "../PBpblas.h"
15 #include "../PBtools.h"
16 #include "../PBblacs.h"
17 #include "../PBblas.h"
18
19 #ifdef __STDC__
20 char * PB_Ctop( int * ICTXT, char * OP, char * SCOPE, char * TOP )
21 #else
22 char * PB_Ctop( ICTXT, OP, SCOPE, TOP )
23 /*
24 * .. Scalar Arguments ..
25 */
26  int * ICTXT;
27 /*
28 * .. Array Arguments ..
29 */
30  char * OP, * SCOPE, * TOP;
31 #endif
32 {
33 /*
34 * Purpose
35 * =======
36 *
37 * PB_Ctop returns or initializes the row-, column- or all- broadcast
38 * or combine topologies.
39 *
40 * Arguments
41 * =========
42 *
43 * ICTXT (local input) INTEGER
44 * On entry, ICTXT specifies the BLACS context handle, indica-
45 * ting the global context of the operation. The context itself
46 * is global, but the value of ICTXT is local.
47 *
48 * OP (global input) pointer to CHAR
49 * On input, OP specifies the BLACS operation defined as fol-
50 * lows:
51 * OP = 'B' or 'b', BLACS broadcast operation,
52 * OP = 'C' or 'c', BLACS combine operation.
53 *
54 * SCOPE (global input) pointer to CHAR
55 * On entry, SCOPE specifies the scope of the BLACS operation as
56 * follows:
57 * SCOPE = 'R' or 'r', rowwise broadcast or combine,
58 * SCOPE = 'C' or 'c', column broadcast or combine,
59 * SCOPE = 'A' or 'a', all broadcast or combine.
60 *
61 * TOP (global input) pointer to CHAR
62 * On entry, TOP is a character string specifying the BLACS to-
63 * pology to be used i.e. to be set for the given operation spe-
64 * cified by OP and SCOPE. If TOP = TOP_GET, the routine instead
65 * returns the current topology in use for the given operation
66 * specified by OP and SCOPE.
67 *
68 * -- Written on April 1, 1998 by
69 * Antoine Petitet, University of Tennessee, Knoxville 37996, USA.
70 *
71 * ---------------------------------------------------------------------
72 */
73 /*
74 * .. Local Scalars ..
75 */
76  static char rbtop = CTOP_DEFAULT;
77  static char cbtop = CTOP_DEFAULT;
78  static char abtop = CTOP_DEFAULT;
79  static char rctop = CTOP_DEFAULT;
80  static char cctop = CTOP_DEFAULT;
81  static char actop = CTOP_DEFAULT;
82 /* ..
83 * .. Executable Statements ..
84 *
85 */
86 /*
87 * This BLACS topology information should be cached within a BLACS context.
88 * This will be corrected in the near future. Sorry.
89 */
90  if( *OP == CBCAST )
91  {
92 /*
94 */
95  if( *TOP == CTOP_GET )
96  {
97 /*
98 * retrieve the current topology in SCOPE
99 */
100  if( *SCOPE == CROW ) { return( &rbtop ); }
101  else if( *SCOPE == CCOLUMN ) { return( &cbtop ); }
102  else { return( &abtop ); }
103  }
104  else
105  {
106 /*
107 * set the topology to be used from now on in SCOPE
108 */
109  if( *SCOPE == CROW ) { rbtop = *TOP; return( &rbtop ); }
110  else if( *SCOPE == CCOLUMN ) { cbtop = *TOP; return( &cbtop ); }
111  else { abtop = *TOP; return( &abtop ); }
112  }
113  }
114  else
115  {
116 /*
117 * BLACS combine operations
118 */
119  if( *TOP == CTOP_GET )
120  {
121 /*
122 * retrieve the current topology in SCOPE
123 */
124  if( *SCOPE == CROW ) { return( &rctop ); }
125  else if( *SCOPE == CCOLUMN ) { return( &cctop ); }
126  else { return( &actop ); }
127  }
128  else
129  {
130 /*
131 * set the topology to be used from now on in SCOPE
132 */
133  if( *SCOPE == CROW ) { rctop = *TOP; return( &rctop ); }
134  else if( *SCOPE == CCOLUMN ) { cctop = *TOP; return( &cctop ); }
135  else { actop = *TOP; return( &actop ); }
136  }
137  }
138 /*
139 * End of PB_Ctop
140 */
141 }
PB_Ctop
char * PB_Ctop(int *ICTXT, char *OP, char *SCOPE, char *TOP)
Definition: PB_Ctop.c:22
CTOP_GET
#define CTOP_GET
Definition: PBblacs.h:25
CBCAST
#define CBCAST
Definition: PBblacs.h:23
CROW
#define CROW
Definition: PBblacs.h:21
CCOLUMN
#define CCOLUMN
Definition: PBblacs.h:20
CTOP_DEFAULT
#define CTOP_DEFAULT
Definition: PBblacs.h:26