# p?lawil

Forms the Wilkinson transform.

## Syntax

call pslawil(ii, jj, m, a, desca, h44, h33, h43h34, v)

call pdlawil(ii, jj, m, a, desca, h44, h33, h43h34, v)

## Description

This routine gets the transform given by h44, h33, and h43h34 into v starting at row m.

## Input Parameters

ii

  (global) INTEGER.

  Row owner of h(m+2, m+2).

jj

  (global) INTEGER.

  Column owner of h(m+2, m+2).

m

  (global) INTEGER.

  On entry, the location from where the transform starts (row m). Unchanged on exit.

a

  (global)

  REAL for pslawil

  DOUBLE PRECISION for pdlawil

  Array, DIMENSION (desca(lld_),*).

  On entry, the Hessenberg matrix. Unchanged on exit.

desca

  (global and local) INTEGER

  Array of DIMENSION (dlen_). The array descriptor for the distributed matrix A. Unchanged on exit.

h43h34

  (global)

  REAL for pslawil

  DOUBLE PRECISION for pdlawil

  These three values are for the double shift QR iteration. Unchanged on exit.

## Output Parameters

v

  (global)

  REAL for pslawil

  DOUBLE PRECISION for pdlawil

  Array of size 3 that contains the transform on output.

Parent topic: Auxiliary Routines