# HPL_plindx10 man page

HPL_plindx10 — Compute the logarithmic maps for the spreading.

## Synopsis

**#include "hpl.h"****void HPL_plindx10( HPL_T_panel *** *PANEL*, **const int** *K*, **const int *** *IPID*, **int *** *IPLEN*, **int *** *IPMAP*, **int *** *IPMAPM1* **);**

## Description

**HPL_plindx10** computes three arrays IPLEN, IPMAP and IPMAPM1 that contain the logarithmic mapping information for the spreading phase.

## Arguments

- PANEL (local input/output) HPL_T_panel *
- On entry, PANEL points to the data structure containing the panel information.
- K (global input) const int
- On entry, K specifies the number of entries in IPID. K is at least 2*N, and at most 4*N.
- IPID (global input) const int *
- On entry, IPID is an array of length K. The first K entries of that array contain the src and final destination resulting from the application of the interchanges.
- IPLEN (global output) int *
- On entry, IPLEN is an array of dimension NPROW + 1. On exit, this array is such that IPLEN[i] is the number of rows of A in the processes before process IMAP[i] after the sort, with the convention that IPLEN[nprow] is the total number of rows. In other words, IPLEN[i+1] - IPLEN[i] is the local number of rows of A that should be moved for each process. IPLEN is such that the number of rows of the source process row can be computed as IPLEN[1] - IPLEN[0], and the remaining entries of this array are sorted so that the quantities IPLEN[i+1] - IPLEN[i] are logarithmically sorted.
- IPMAP (global output) int *
- On entry, IPMAP is an array of dimension NPROW. On exit, this array contains the logarithmic mapping of the processes. In other words, IPMAP[myrow] is the corresponding sorted process coordinate.
- IPMAPM1 (global output) int *
- On entry, IPMAPM1 is an array of dimension NPROW. On exit, this array contains the inverse of the logarithmic mapping contained in IPMAP: IPMAPM1[ IPMAP[i] ] = i, for all i in [0.. NPROW)

## See Also

**HPL_pdlaswp00N** (3), **HPL_pdlaswp00T** (3), **HPL_pdlaswp01N** (3), **HPL_pdlaswp01T** (3).