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| 3 | 1 | equemene | <TITLE>HPL_pdlaswp01T HPL 2.0 Library Functions September 10, 2008</TITLE> |
| 4 | 1 | equemene | </HEAD>
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| 8 | 1 | equemene | |
| 9 | 1 | equemene | <H1>Name</H1> |
| 10 | 1 | equemene | <B>HPL_pdlaswp01T</B> Broadcast a column panel L and swap the row panel U. |
| 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_pdlaswp01T(</CODE> |
| 16 | 1 | equemene | <CODE>HPL_T_panel *</CODE> |
| 17 | 1 | equemene | <CODE>PBCST</CODE>, |
| 18 | 1 | equemene | <CODE>int *</CODE> |
| 19 | 1 | equemene | <CODE>IFLAG</CODE>, |
| 20 | 1 | equemene | <CODE>HPL_T_panel *</CODE> |
| 21 | 1 | equemene | <CODE>PANEL</CODE>, |
| 22 | 1 | equemene | <CODE>const int</CODE> |
| 23 | 1 | equemene | <CODE>NN</CODE> |
| 24 | 1 | equemene | <CODE>);</CODE> |
| 25 | 1 | equemene | |
| 26 | 1 | equemene | <H1>Description</H1> |
| 27 | 1 | equemene | <B>HPL_pdlaswp01T</B> |
| 28 | 1 | equemene | applies the NB row interchanges to NN columns of the |
| 29 | 1 | equemene | trailing submatrix and broadcast a column panel. |
| 30 | 1 | equemene | |
| 31 | 1 | equemene | A "Spread then roll" algorithm performs the swap :: broadcast of the |
| 32 | 1 | equemene | row panel U at once, resulting in a minimal communication volume and |
| 33 | 1 | equemene | a "very good" use of the connectivity if available. With P process |
| 34 | 1 | equemene | rows and assuming bi-directional links, the running time of this |
| 35 | 1 | equemene | function can be approximated by: |
| 36 | 1 | equemene | |
| 37 | 1 | equemene | (log_2(P)+(P-1)) * lat + K * NB * LocQ(N) / bdwth |
| 38 | 1 | equemene | |
| 39 | 1 | equemene | where NB is the number of rows of the row panel U, N is the global |
| 40 | 1 | equemene | number of columns being updated, lat and bdwth are the latency and |
| 41 | 1 | equemene | bandwidth of the network for double precision real words. K is |
| 42 | 1 | equemene | a constant in (2,3] that depends on the achieved bandwidth during a |
| 43 | 1 | equemene | simultaneous message exchange between two processes. An empirical |
| 44 | 1 | equemene | optimistic value of K is typically 2.4. |
| 45 | 1 | equemene | |
| 46 | 1 | equemene | <H1>Arguments</H1> |
| 47 | 1 | equemene | <PRE>
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| 48 | 1 | equemene | PBCST (local input/output) HPL_T_panel * |
| 49 | 1 | equemene | On entry, PBCST points to the data structure containing the |
| 50 | 1 | equemene | panel (to be broadcast) information. |
| 51 | 1 | equemene | </PRE>
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| 52 | 1 | equemene | <PRE>
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| 53 | 1 | equemene | IFLAG (local input/output) int * |
| 54 | 1 | equemene | On entry, IFLAG indicates whether or not the broadcast has |
| 55 | 1 | equemene | already been completed. If not, probing will occur, and the |
| 56 | 1 | equemene | outcome will be contained in IFLAG on exit. |
| 57 | 1 | equemene | </PRE>
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| 58 | 1 | equemene | <PRE>
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| 59 | 1 | equemene | PANEL (local input/output) HPL_T_panel * |
| 60 | 1 | equemene | On entry, PANEL points to the data structure containing the |
| 61 | 1 | equemene | panel information. |
| 62 | 1 | equemene | </PRE>
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| 63 | 1 | equemene | <PRE>
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| 64 | 1 | equemene | NN (local input) const int |
| 65 | 1 | equemene | On entry, NN specifies the local number of columns of the |
| 66 | 1 | equemene | trailing submatrix to be swapped and broadcast starting at |
| 67 | 1 | equemene | the current position. NN must be at least zero. |
| 68 | 1 | equemene | </PRE>
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| 69 | 1 | equemene | |
| 70 | 1 | equemene | <H1>See Also</H1> |
| 71 | 1 | equemene | <A HREF="HPL_pdgesv.html">HPL_pdgesv</A>, |
| 72 | 1 | equemene | <A HREF="HPL_pdgesvK2.html">HPL_pdgesvK2</A>, |
| 73 | 1 | equemene | <A HREF="HPL_pdupdateNT.html">HPL_pdupdateNT</A>, |
| 74 | 1 | equemene | <A HREF="HPL_pdupdateTT.html">HPL_pdupdateTT</A>, |
| 75 | 1 | equemene | <A HREF="HPL_pipid.html">HPL_pipid</A>, |
| 76 | 1 | equemene | <A HREF="HPL_plindx1.html">HPL_plindx1</A>, |
| 77 | 1 | equemene | <A HREF="HPL_plindx10.html">HPL_plindx10</A>, |
| 78 | 1 | equemene | <A HREF="HPL_spreadT.html">HPL_spreadT</A>, |
| 79 | 1 | equemene | <A HREF="HPL_equil.html">HPL_equil</A>, |
| 80 | 1 | equemene | <A HREF="HPL_rollT.html">HPL_rollT</A>, |
| 81 | 1 | equemene | <A HREF="HPL_dlaswp10N.html">HPL_dlaswp10N</A>, |
| 82 | 1 | equemene | <A HREF="HPL_dlaswp01T.html">HPL_dlaswp01T</A>, |
| 83 | 1 | equemene | <A HREF="HPL_dlaswp06T.html">HPL_dlaswp06T</A>. |
| 84 | 1 | equemene | |
| 85 | 1 | equemene | </BODY>
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| 86 | 1 | equemene | </HTML> |