NAME

SYNOPSIS

void HPL_pdlaswp00N( HPL_T_panel * PBCST, int * IFLAG, HPL_T_panel * PANEL, const int NN );

DESCRIPTION

Bi-directional exchange is used to perform the swap :: broadcast of the row panel U at once, resulting in a lower number of messages than usual as well as a lower communication volume. With P process rows and assuming bi-directional links, the running time of this function can be approximated by:

log_2(P) * (lat + NB*LocQ(N) / bdwth)

where NB is the number of rows of the row panel U, N is the global number of columns being updated, lat and bdwth are the latency and bandwidth of the network for double precision real words. Mono directional links will double this communication cost.

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 already 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 (to be broadcast and swapped) 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