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view extra/bim/inst/bim2a_axisymmetric_rhs.m @ 12628:4cacfa5f9470 octave-forge
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author | cdf |
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date | Mon, 08 Jun 2015 08:51:06 +0000 |
parents | afa2a6681ec6 |
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## Copyright (C) 2006-2014 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> ## author: Matteo porro <meoo85 _AT_ users.sourceforge.net> ## author: Emanuela Abbate <emanuela.abbate _AT_ mail.polimi.it> ## -*- texinfo -*- ## @deftypefn {Function File} {[@var{b}]} = @ ## bim2a_axisymmetric_rhs(@var{mesh},@var{f},@var{g}) ## ## Build the finite element right-hand side of a diffusion problem ## in cylindrical coordinates with axisymmetric configuration ## employing mass-lumping. ## ## The equation taken into account is: ## ## @var{delta} * u = f * g ## ## where @var{f} is an element-wise constant scalar function, while ## @var{g} is a piecewise linear conforming scalar function. ## ## @seealso{bim2a_axisymmetric_reaction, bim2a_axisymmetric_advection_diffusion, ## bim2a_axisymmetric_laplacian, bim1a_axisymmetric_rhs} ## @end deftypefn function b = bim2a_axisymmetric_rhs(mesh,f,g) ## Check input if (nargin != 3) error("bim2a_axisymmetric_rhs: wrong number of input parameters."); elseif !(isstruct(mesh) && isfield(mesh,"p") && isfield (mesh,"t") && isfield(mesh,"e")) error("bim2a_axisymmetric_rhs: first input is not a valid mesh structure."); elseif !(all(mesh.p(1,:) >= 0) || all(mesh.p(1,:) <= 0)) error("bim2a_axisymmetric_rhs: the input mesh cannot intersect the rotation axis r=0."); endif nnodes = columns(mesh.p); nelem = columns(mesh.t); r = abs (mesh.p(1,:)); ## Turn scalar input to a vector of appropriate size if isscalar(f) f = f*ones(nelem,1); endif if isscalar(g) g = g*ones(nnodes,1); endif if !( isvector(f) && isvector(g) ) error("bim2a_axisymmetric_rhs: coefficients are not valid vectors."); elseif length(f) != nelem error("bim2a_axisymmetric_rhs: length of f is not equal to the number of elements."); elseif length(g) != nnodes error("bim2a_axisymmetric_rhs: length of g is not equal to the number of nodes."); endif g = g(mesh.t(1:3,:)); wjacdet = mesh.wjacdet; ## Build local matrix Blocmat = zeros(3,nelem); for inode = 1:3 Blocmat(inode,:) = f'.*g(inode,:).*wjacdet(inode,:) .* r(mesh.t(inode,:)); endfor gnode = (mesh.t(1:3,:)); ## Assemble global matrix b = sparse(gnode(:),1,Blocmat(:)); endfunction %!shared mesh,f,g,nnodes,nelem % x = y = linspace(0,1,4); % [mesh] = msh2m_structured_mesh(x,y,1,1:4); % [mesh] = bim2c_mesh_properties(mesh); % nnodes = columns(mesh.p); % nelem = columns(mesh.t); % g = ones(columns(mesh.t),1); % f = ones(columns(mesh.p),1); %!test % [b] = bim2a_axisymmetric_rhs(mesh,f,g); % assert(size(b),[nnodes, 1]); %!test % [b1] = bim2a_axisymmetric_rhs(mesh,3*f,g); % [b2] = bim2a_axisymmetric_rhs(mesh,f,3*g); % assert(b1,b2); %!test % [b1] = bim2a_axisymmetric_rhs(mesh,3*f,g); % [b2] = bim2a_axisymmetric_rhs(mesh,3,1); % assert(b1,b2);