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| 2 | 1 | equemene | <HEAD>
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| 3 | 1 | equemene | <TITLE>HPL_pdmxswp HPL 2.0 Library Functions September 10, 2008</TITLE> |
| 4 | 1 | equemene | </HEAD>
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| 5 | 1 | equemene | |
| 6 | 1 | equemene | <BODY BGCOLOR="WHITE" TEXT = "#000000" LINK = "#0000ff" VLINK = "#000099" |
| 7 | 1 | equemene | ALINK = "#ffff00"> |
| 8 | 1 | equemene | |
| 9 | 1 | equemene | <H1>Name</H1> |
| 10 | 1 | equemene | <B>HPL_pdmxswp</B> swaps and broacast the pivot row. |
| 11 | 1 | equemene | |
| 12 | 1 | equemene | <H1>Synopsis</H1> |
| 13 | 1 | equemene | <CODE>#include "hpl.h"</CODE><BR><BR> |
| 14 | 1 | equemene | <CODE>void</CODE> |
| 15 | 1 | equemene | <CODE>HPL_pdmxswp(</CODE> |
| 16 | 1 | equemene | <CODE>HPL_T_panel *</CODE> |
| 17 | 1 | equemene | <CODE>PANEL</CODE>, |
| 18 | 1 | equemene | <CODE>const int</CODE> |
| 19 | 1 | equemene | <CODE>M</CODE>, |
| 20 | 1 | equemene | <CODE>const int</CODE> |
| 21 | 1 | equemene | <CODE>II</CODE>, |
| 22 | 1 | equemene | <CODE>const int</CODE> |
| 23 | 1 | equemene | <CODE>JJ</CODE>, |
| 24 | 1 | equemene | <CODE>double *</CODE> |
| 25 | 1 | equemene | <CODE>WORK</CODE> |
| 26 | 1 | equemene | <CODE>);</CODE> |
| 27 | 1 | equemene | |
| 28 | 1 | equemene | <H1>Description</H1> |
| 29 | 1 | equemene | <B>HPL_pdmxswp</B> |
| 30 | 1 | equemene | swaps and broadcasts the absolute value max row using |
| 31 | 1 | equemene | bi-directional exchange. The buffer is partially set by HPL_dlocmax. |
| 32 | 1 | equemene | |
| 33 | 1 | equemene | Bi-directional exchange is used to perform the swap::broadcast |
| 34 | 1 | equemene | operations at once for one column in the panel. This results in a |
| 35 | 1 | equemene | lower number of slightly larger messages than usual. On P processes |
| 36 | 1 | equemene | and assuming bi-directional links, the running time of this function |
| 37 | 1 | equemene | can be approximated by |
| 38 | 1 | equemene | |
| 39 | 1 | equemene | log_2( P ) * ( lat + ( 2 * N0 + 4 ) / bdwth ) |
| 40 | 1 | equemene | |
| 41 | 1 | equemene | where lat and bdwth are the latency and bandwidth of the network for |
| 42 | 1 | equemene | double precision real elements. Communication only occurs in one |
| 43 | 1 | equemene | process column. Mono-directional links will cause the communication |
| 44 | 1 | equemene | cost to double. |
| 45 | 1 | equemene | |
| 46 | 1 | equemene | <H1>Arguments</H1> |
| 47 | 1 | equemene | <PRE>
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| 48 | 1 | equemene | PANEL (local input/output) HPL_T_panel * |
| 49 | 1 | equemene | On entry, PANEL points to the data structure containing the |
| 50 | 1 | equemene | panel information. |
| 51 | 1 | equemene | </PRE>
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| 52 | 1 | equemene | <PRE>
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| 53 | 1 | equemene | M (local input) const int |
| 54 | 1 | equemene | On entry, M specifies the local number of rows of the matrix |
| 55 | 1 | equemene | column on which this function operates. |
| 56 | 1 | equemene | </PRE>
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| 57 | 1 | equemene | <PRE>
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| 58 | 1 | equemene | II (local input) const int |
| 59 | 1 | equemene | On entry, II specifies the row offset where the column to be |
| 60 | 1 | equemene | operated on starts with respect to the panel. |
| 61 | 1 | equemene | </PRE>
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| 62 | 1 | equemene | <PRE>
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| 63 | 1 | equemene | JJ (local input) const int |
| 64 | 1 | equemene | On entry, JJ specifies the column offset where the column to |
| 65 | 1 | equemene | be operated on starts with respect to the panel. |
| 66 | 1 | equemene | </PRE>
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| 67 | 1 | equemene | <PRE>
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| 68 | 1 | equemene | WORK (local workspace) double * |
| 69 | 1 | equemene | On entry, WORK is a workarray of size at least 2 * (4+2*N0). |
| 70 | 1 | equemene | It is assumed that HPL_dlocmax was called prior to this |
| 71 | 1 | equemene | routine to initialize the first four entries of this array. |
| 72 | 1 | equemene | On exit, the N0 length max row is stored in WORK[4:4+N0-1]; |
| 73 | 1 | equemene | Note that this is also the JJth row (or column) of L1. The |
| 74 | 1 | equemene | remaining part is used as a temporary array. |
| 75 | 1 | equemene | </PRE>
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| 76 | 1 | equemene | |
| 77 | 1 | equemene | <H1>See Also</H1> |
| 78 | 1 | equemene | <A HREF="HPL_dlocmax.html">HPL_dlocmax</A>, |
| 79 | 1 | equemene | <A HREF="HPL_dlocswpN.html">HPL_dlocswpN</A>, |
| 80 | 1 | equemene | <A HREF="HPL_dlocswpT.html">HPL_dlocswpT</A>, |
| 81 | 1 | equemene | <A HREF="HPL_pdpancrN.html">HPL_pdpancrN</A>, |
| 82 | 1 | equemene | <A HREF="HPL_pdpancrT.html">HPL_pdpancrT</A>, |
| 83 | 1 | equemene | <A HREF="HPL_pdpanllN.html">HPL_pdpanllN</A>, |
| 84 | 1 | equemene | <A HREF="HPL_pdpanllT.html">HPL_pdpanllT</A>, |
| 85 | 1 | equemene | <A HREF="HPL_pdpanrlN.html">HPL_pdpanrlN</A>, |
| 86 | 1 | equemene | <A HREF="HPL_pdpanrlT.html">HPL_pdpanrlT</A>, |
| 87 | 1 | equemene | <A HREF="HPL_pdrpancrN.html">HPL_pdrpancrN</A>, |
| 88 | 1 | equemene | <A HREF="HPL_pdrpancrT.html">HPL_pdrpancrT</A>, |
| 89 | 1 | equemene | <A HREF="HPL_pdrpanllN.html">HPL_pdrpanllN</A>, |
| 90 | 1 | equemene | <A HREF="HPL_pdrpanllT.html">HPL_pdrpanllT</A>, |
| 91 | 1 | equemene | <A HREF="HPL_pdrpanrlN.html">HPL_pdrpanrlN</A>, |
| 92 | 1 | equemene | <A HREF="HPL_pdrpanrlT.html">HPL_pdrpanrlT</A>, |
| 93 | 1 | equemene | <A HREF="HPL_pdfact.html">HPL_pdfact</A>. |
| 94 | 1 | equemene | |
| 95 | 1 | equemene | </BODY>
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| 96 | 1 | equemene | </HTML> |