# Name

HPL_spreadN Spread row panel U and forward current column panel.

# Synopsis

`#include "hpl.h"`
`void` `HPL_spreadN(` `HPL_T_panel *` `PBCST`, `int *` `IFLAG`, `HPL_T_panel *` `PANEL`, `const enum HPL_SIDE` `SIDE`, `const int` `N`, `double *` `U`, `const int` `LDU`, `const int` `SRCDIST`, `const int *` `IPLEN`, `const int *` `IPMAP`, `const int *` `IPMAPM1` `);`

# Description

HPL_spreadN spreads the local array containing local pieces of U, so that on exit to this function, a piece of U is contained in every process row. The array IPLEN contains the number of rows of U, that should be spread on any given process row. This function also probes for the presence of the column panel PBCST. In case of success, this panel will be forwarded. If PBCST is NULL on input, this probing mechanism will be disabled.

# 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 spread) information.

    SIDE    (global input)                const enum HPL_SIDE
            On entry, SIDE specifies whether the local piece of U located
            in process IPMAP[SRCDIST] should be spread to the right or to
            the left. This feature is used by the equilibration process.

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

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

    LDU     (local input)                 const int
            On entry, LDU specifies the local leading dimension of U. LDU
            should be at least MAX(1,IPLEN[nprow]).

    SRCDIST (local input)                 const int
            On entry,  SRCDIST  specifies the source process that spreads
            its piece of U.

    IPLEN   (global input)                const 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 each process before process IPMAP[i], 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 U that
            should be moved to 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.. NPROW) IPMAPM1[IPMAP[i]] = i.

# See Also

HPL_pdlaswp01N.