root / src / pfact / HPL_pdfact.c @ 7
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| 1 | 1 | equemene | /*
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| 2 | 1 | equemene | * -- High Performance Computing Linpack Benchmark (HPL)
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| 3 | 1 | equemene | * HPL - 2.0 - September 10, 2008
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| 4 | 1 | equemene | * Antoine P. Petitet
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| 5 | 1 | equemene | * University of Tennessee, Knoxville
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| 6 | 1 | equemene | * Innovative Computing Laboratory
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| 7 | 1 | equemene | * (C) Copyright 2000-2008 All Rights Reserved
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| 8 | 1 | equemene | *
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| 9 | 1 | equemene | * -- Copyright notice and Licensing terms:
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| 10 | 1 | equemene | *
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| 11 | 1 | equemene | * Redistribution and use in source and binary forms, with or without
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| 12 | 1 | equemene | * modification, are permitted provided that the following conditions
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| 13 | 1 | equemene | * are met:
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| 14 | 1 | equemene | *
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| 15 | 1 | equemene | * 1. Redistributions of source code must retain the above copyright
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| 16 | 1 | equemene | * notice, this list of conditions and the following disclaimer.
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| 17 | 1 | equemene | *
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| 18 | 1 | equemene | * 2. Redistributions in binary form must reproduce the above copyright
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| 19 | 1 | equemene | * notice, this list of conditions, and the following disclaimer in the
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| 20 | 1 | equemene | * documentation and/or other materials provided with the distribution.
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| 21 | 1 | equemene | *
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| 22 | 1 | equemene | * 3. All advertising materials mentioning features or use of this
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| 23 | 1 | equemene | * software must display the following acknowledgement:
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| 24 | 1 | equemene | * This product includes software developed at the University of
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| 25 | 1 | equemene | * Tennessee, Knoxville, Innovative Computing Laboratory.
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| 26 | 1 | equemene | *
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| 27 | 1 | equemene | * 4. The name of the University, the name of the Laboratory, or the
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| 28 | 1 | equemene | * names of its contributors may not be used to endorse or promote
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| 29 | 1 | equemene | * products derived from this software without specific written
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| 30 | 1 | equemene | * permission.
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| 31 | 1 | equemene | *
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| 32 | 1 | equemene | * -- Disclaimer:
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| 33 | 1 | equemene | *
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| 34 | 1 | equemene | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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| 35 | 1 | equemene | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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| 36 | 1 | equemene | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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| 37 | 1 | equemene | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY
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| 38 | 1 | equemene | * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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| 39 | 1 | equemene | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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| 40 | 1 | equemene | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 41 | 1 | equemene | * DATA OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 42 | 1 | equemene | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 43 | 1 | equemene | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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| 44 | 1 | equemene | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 45 | 1 | equemene | * ---------------------------------------------------------------------
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| 46 | 1 | equemene | */
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| 47 | 1 | equemene | /*
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| 48 | 1 | equemene | * Include files
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| 49 | 1 | equemene | */
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| 50 | 1 | equemene | #include "hpl.h" |
| 51 | 1 | equemene | |
| 52 | 1 | equemene | #ifdef STDC_HEADERS
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| 53 | 1 | equemene | void HPL_pdfact
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| 54 | 1 | equemene | ( |
| 55 | 1 | equemene | HPL_T_panel * PANEL |
| 56 | 1 | equemene | ) |
| 57 | 1 | equemene | #else
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| 58 | 1 | equemene | void HPL_pdfact
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| 59 | 1 | equemene | ( PANEL ) |
| 60 | 1 | equemene | HPL_T_panel * PANEL; |
| 61 | 1 | equemene | #endif
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| 62 | 1 | equemene | {
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| 63 | 1 | equemene | /*
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| 64 | 1 | equemene | * Purpose
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| 65 | 1 | equemene | * =======
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| 66 | 1 | equemene | *
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| 67 | 1 | equemene | * HPL_pdfact recursively factorizes a 1-dimensional panel of columns.
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| 68 | 1 | equemene | * The RPFACT function pointer specifies the recursive algorithm to be
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| 69 | 1 | equemene | * used, either Crout, Left- or Right looking. NBMIN allows to vary the
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| 70 | 1 | equemene | * recursive stopping criterium in terms of the number of columns in the
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| 71 | 1 | equemene | * panel, and NDIV allow to specify the number of subpanels each panel
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| 72 | 1 | equemene | * should be divided into. Usuallly a value of 2 will be chosen. Finally
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| 73 | 1 | equemene | * PFACT is a function pointer specifying the non-recursive algorithm to
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| 74 | 1 | equemene | * to be used on at most NBMIN columns. One can also choose here between
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| 75 | 1 | equemene | * Crout, Left- or Right looking. Empirical tests seem to indicate that
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| 76 | 1 | equemene | * values of 4 or 8 for NBMIN give the best results.
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| 77 | 1 | equemene | *
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| 78 | 1 | equemene | * Bi-directional exchange is used to perform the swap::broadcast
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| 79 | 1 | equemene | * operations at once for one column in the panel. This results in a
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| 80 | 1 | equemene | * lower number of slightly larger messages than usual. On P processes
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| 81 | 1 | equemene | * and assuming bi-directional links, the running time of this function
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| 82 | 1 | equemene | * can be approximated by (when N is equal to N0):
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| 83 | 1 | equemene | *
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| 84 | 1 | equemene | * N0 * log_2( P ) * ( lat + ( 2*N0 + 4 ) / bdwth ) +
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| 85 | 1 | equemene | * N0^2 * ( M - N0/3 ) * gam2-3
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| 86 | 1 | equemene | *
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| 87 | 1 | equemene | * where M is the local number of rows of the panel, lat and bdwth are
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| 88 | 1 | equemene | * the latency and bandwidth of the network for double precision real
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| 89 | 1 | equemene | * words, and gam2-3 is an estimate of the Level 2 and Level 3 BLAS
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| 90 | 1 | equemene | * rate of execution. The recursive algorithm allows indeed to almost
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| 91 | 1 | equemene | * achieve Level 3 BLAS performance in the panel factorization. On a
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| 92 | 1 | equemene | * large number of modern machines, this operation is however latency
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| 93 | 1 | equemene | * bound, meaning that its cost can be estimated by only the latency
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| 94 | 1 | equemene | * portion N0 * log_2(P) * lat. Mono-directional links will double this
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| 95 | 1 | equemene | * communication cost.
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| 96 | 1 | equemene | *
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| 97 | 1 | equemene | * Arguments
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| 98 | 1 | equemene | * =========
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| 99 | 1 | equemene | *
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| 100 | 1 | equemene | * PANEL (local input/output) HPL_T_panel *
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| 101 | 1 | equemene | * On entry, PANEL points to the data structure containing the
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| 102 | 1 | equemene | * panel information.
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| 103 | 1 | equemene | *
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| 104 | 1 | equemene | * ---------------------------------------------------------------------
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| 105 | 1 | equemene | */
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| 106 | 1 | equemene | /*
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| 107 | 1 | equemene | * .. Local Variables ..
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| 108 | 1 | equemene | */
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| 109 | 1 | equemene | void * vptr = NULL; |
| 110 | 1 | equemene | int align, jb;
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| 111 | 1 | equemene | /* ..
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| 112 | 1 | equemene | * .. Executable Statements ..
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| 113 | 1 | equemene | */
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| 114 | 1 | equemene | jb = PANEL->jb; PANEL->n -= jb; PANEL->ja += jb; |
| 115 | 1 | equemene | |
| 116 | 1 | equemene | if( ( PANEL->grid->mycol != PANEL->pcol ) || ( jb <= 0 ) ) return; |
| 117 | 1 | equemene | #ifdef HPL_DETAILED_TIMING
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| 118 | 1 | equemene | HPL_ptimer( HPL_TIMING_RPFACT ); |
| 119 | 1 | equemene | #endif
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| 120 | 1 | equemene | align = PANEL->algo->align; |
| 121 | 1 | equemene | vptr = (void *)malloc( ( (size_t)(align) +
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| 122 | 1 | equemene | (size_t)(((4+((unsigned int)(jb) << 1)) << 1) )) * |
| 123 | 1 | equemene | sizeof(double) ); |
| 124 | 1 | equemene | if( vptr == NULL ) |
| 125 | 1 | equemene | { HPL_pabort( __LINE__, "HPL_pdfact", "Memory allocation failed" ); }
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| 126 | 1 | equemene | /*
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| 127 | 1 | equemene | * Factor the panel - Update the panel pointers
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| 128 | 1 | equemene | */
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| 129 | 1 | equemene | PANEL->algo->rffun( PANEL, PANEL->mp, jb, 0, (double *)HPL_PTR( vptr, |
| 130 | 1 | equemene | ((size_t)(align) * sizeof(double) ) ) ); |
| 131 | 1 | equemene | if( vptr ) free( vptr );
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| 132 | 1 | equemene | |
| 133 | 1 | equemene | PANEL->A = Mptr( PANEL->A, 0, jb, PANEL->lda );
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| 134 | 1 | equemene | PANEL->nq -= jb; PANEL->jj += jb; |
| 135 | 1 | equemene | #ifdef HPL_DETAILED_TIMING
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| 136 | 1 | equemene | HPL_ptimer( HPL_TIMING_RPFACT ); |
| 137 | 1 | equemene | #endif
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| 138 | 1 | equemene | /*
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| 139 | 1 | equemene | * End of HPL_pdfact
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| 140 | 1 | equemene | */
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| 141 | 1 | equemene | } |