HPL_pdlaswp01T(3) HPL Library Functions HPL_pdlaswp01T(3) NAME HPL_pdlaswp01T - Broadcast a column panel L and swap the row panel U. SYNOPSIS #include "hpl.h" void HPL_pdlaswp01T( HPL_T_panel * PBCST, int * IFLAG, HPL_T_panel * PANEL, const int NN ); DESCRIPTION HPL_pdlaswp01T applies the NB row interchanges to NN columns of the trailing submatrix and broadcast a column panel. A "Spread then roll" algorithm performs the swap :: broadcast of the row panel U at once, resulting in a minimal communication volume and a "very good" use of the connectivity if available. With P process rows and assuming bi-directional links, the running time of this function can be approximated by: (log_2(P)+(P-1)) * lat + K * NB * LocQ(N) / bdwth where NB is the number of rows of the row panel U, N is the global num- ber of columns being updated, lat and bdwth are the latency and band- width of the network for double precision real words. K is a con- stant in (2,3] that depends on the achieved bandwidth during a simultane- ous message exchange between two processes. An empirical optimistic value of K is typically 2.4. ARGUMENTS PBCST (local input/output) HPL_T_panel * On entry, PBCST points to the data structure containing the panel (to be broadcast) information. IFLAG (local input/output) int * On entry, IFLAG indicates whether or not the broadcast has al- ready been completed. If not, probing will occur, and the outcome will be contained in IFLAG on exit. PANEL (local input/output) HPL_T_panel * On entry, PANEL points to the data structure containing the panel information. NN (local input) const int On entry, NN specifies the local number of columns of the trailing submatrix to be swapped and broadcast starting at the current position. NN must be at least zero. SEE ALSO HPL_pdgesv (3), HPL_pdgesvK2 (3), HPL_pdupdateNT (3), HPL_pdupdateTT (3), HPL_pipid (3), HPL_plindx1 (3), HPL_plindx10 (3), HPL_spreadT (3), HPL_equil (3), HPL_rollT (3), HPL_dlaswp10N (3), HPL_dlaswp01T (3), HPL_dlaswp06T (3). HPL 2.3 December 2, 2018 HPL_pdlaswp01T(3)
NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | SEE ALSO
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