Mercurial > forge
view extra/bim/inst/bim3c_pde_gradient.m @ 12412:d3da1a3fda79 octave-forge
do not assume vector direction
author | cdf |
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date | Sun, 30 Mar 2014 16:14:44 +0000 |
parents | 7b91ea5611f4 |
children | 0e3e5de39d88 |
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## 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}, @var{gz}]} = @ ## bim3c_pde_gradient(@var{mesh},@var{u}) ## ## Compute the gradient of the piecewise linear conforming scalar ## function @var{u}. ## ## @seealso{bim3c_global_flux} ## @end deftypefn function [gx, gy, gz] = bim3c_pde_gradient (mesh, u) ## Check input if (nargin != 2) error("bim3c_pde_gradient: wrong number of input parameters."); elseif (! (isstruct (mesh) && isfield (mesh,"p")) && isfield (mesh, "t") && isfield(mesh, "e")) error ("bim3c_pde_gradient: first input is not a valid mesh structure."); endif nnodes = columns (mesh.p); if (numel (u) != nnodes) error ("bim3c_pde_gradient: length(u) != nnodes."); endif gx = sum (squeeze (mesh.shg(1,:,:)) .* u(mesh.t(1:4,:)), 1); gy = sum (squeeze (mesh.shg(2,:,:)) .* u(mesh.t(1:4,:)), 1); gz = sum (squeeze (mesh.shg(3,:,:)) .* u(mesh.t(1:4,:)), 1); endfunction