/usr/share/octave/packages/bim-1.1.5/bim2c_pde_gradient.m is in octave-bim 1.1.5-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | ## Copyright (C) 2006,2007,2008,2009,2010 Carlo de Falco, Massimiliano Culpo
##
## This file is part of:
## BIM - Diffusion Advection Reaction PDE Solver
##
## BIM is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## BIM is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with BIM; If not, see <http://www.gnu.org/licenses/>.
##
## author: Carlo de Falco <cdf _AT_ users.sourceforge.net>
## author: Massimiliano Culpo <culpo _AT_ users.sourceforge.net>
## -*- texinfo -*-
##
## @deftypefn {Function File} {[@var{gx},@var{gy}]} = @
## bim2c_pde_gradient(@var{mesh},@var{u})
##
## Compute the gradient of the piecewise linear conforming scalar
## function @var{u}.
##
## @seealso{bim2c_global_flux}
## @end deftypefn
function [gx, gy] = bim2c_pde_gradient(mesh,u)
## Check input
if nargin != 2
error("bim2c_pde_gradient: wrong number of input parameters.");
elseif !(isstruct(mesh) && isfield(mesh,"p") &&
isfield (mesh,"t") && isfield(mesh,"e"))
error("bim2c_pde_gradient: first input is not a valid mesh structure.");
endif
nnodes = columns(mesh.p);
if (numel (u) != nnodes)
error("bim2c_pde_gradient: length(u) != nnodes.");
endif
shgx = reshape(mesh.shg(1,:,:),3,[]);
gx = sum(shgx.*u(mesh.t(1:3,:)),1);
shgy = reshape(mesh.shg(2,:,:),3,[]);
gy = sum(shgy.*u(mesh.t(1:3,:)),1);
endfunction
|