# Name

**HPL_equil**Equilibrate U and forward the column panel L.

# Synopsis

`#include "hpl.h"`

`void`

`HPL_equil(`

`HPL_T_panel *`

`PBCST`

,
`int *`

`IFLAG`

,
`HPL_T_panel *`

`PANEL`

,
`const enum HPL_TRANS`

`TRANS`

,
`const int`

`N`

,
`double *`

`U`

,
`const int`

`LDU`

,
`int *`

`IPLEN`

,
`const int *`

`IPMAP`

,
`const int *`

`IPMAPM1`

,
`int *`

`IWORK`

`);`

# Description

**HPL_equil**equilibrates the local pieces of U, so that on exit to this function, pieces of U contained in every process row are of the same size. This phase makes the rolling phase optimal. In addition, this function probes for the column panel L and forwards it when possible.

# 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 equilibrated) information.

TRANS (global input) const enum HPL_TRANS On entry, TRANS specifies whether U is stored in transposed or non-transposed form.

N (local input) const int On entry, N specifies the number of rows or columns of U. N must be at least 0.

U (local input/output) double * On entry, U is an array of dimension (LDU,*) containing the local pieces of U in each process row.

LDU (local input) const int On entry, LDU specifies the local leading dimension of U. LDU should be at least MAX(1,IPLEN[nprow]) when U is stored in non-transposed form, and MAX(1,N) otherwise.

IPLEN (global input) int * On entry, IPLEN is an array of dimension NPROW+1. This array is such that IPLEN[i+1] - IPLEN[i] is the number of rows of U in process IPMAP[i].

IPMAP (global input) const int * On entry, IPMAP is an array of dimension NPROW. This array contains the logarithmic mapping of the processes. In other words, IPMAP[myrow] is the absolute coordinate of the sorted process.

IPMAPM1 (global input) const int * On entry, IPMAPM1 is an array of dimension NPROW. This array contains the inverse of the logarithmic mapping contained in IPMAP: For i in [0.. NPROCS) IPMAPM1[IPMAP[i]] = i.

IWORK (workspace) int * On entry, IWORK is a workarray of dimension NPROW+1.