HPL_pdmxswp(3) HPL Library Functions HPL_pdmxswp(3) NAME HPL_pdmxswp - swaps and broacast the pivot row. SYNOPSIS #include "hpl.h" void HPL_pdmxswp( HPL_T_panel * PANEL, const int M, const int II, const int JJ, double * WORK ); DESCRIPTION HPL_pdmxswp swaps and broadcasts the absolute value max row using bi- directional exchange. The buffer is partially set by HPL_dlocmax. Bi-directional exchange is used to perform the swap::broadcast oper- ations at once for one column in the panel. This results in a lower number of slightly larger messages than usual. On P processes and assum- ing bi-directional links, the running time of this function can be approx- imated by log_2( P ) * ( lat + ( 2 * N0 + 4 ) / bdwth ) where lat and bdwth are the latency and bandwidth of the network for dou- ble precision real elements. Communication only occurs in one process column. Mono-directional links will cause the communication cost to dou- ble. ARGUMENTS PANEL (local input/output) HPL_T_panel * On entry, PANEL points to the data structure containing the panel information. M (local input) const int On entry, M specifies the local number of rows of the matrix col- umn on which this function operates. II (local input) const int On entry, II specifies the row offset where the column to be oper- ated on starts with respect to the panel. JJ (local input) const int On entry, JJ specifies the column offset where the column to be operated on starts with respect to the panel. WORK (local workspace) double * On entry, WORK is a workarray of size at least 2 * (4+2*N0). It is assumed that HPL_dlocmax was called prior to this routine to initialize the first four entries of this array. On exit, the N0 length max row is stored in WORK[4:4+N0-1]; Note that this is also the JJth row (or column) of L1. The remaining part is used as a temporary array. SEE ALSO HPL_dlocmax (3), HPL_dlocswpN (3), HPL_dlocswpT (3), HPL_pdpancrN (3), HPL_pdpancrT (3), HPL_pdpanllN (3), HPL_pdpanllT (3), HPL_pdpanrlN (3), HPL_pdpanrlT (3), HPL_pdrpancrN (3), HPL_pdrpancrT (3), HPL_pdrpanllN (3), HPL_pdrpanllT (3), HPL_pdrpanrlN (3), HPL_pdrpanrlT (3), HPL_pdfact (3). HPL 2.3 December 2, 2018 HPL_pdmxswp(3)
NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | SEE ALSO
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