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Minjun Bae on 13 Jan 2020
Commented: Ravi Kumar on 19 Jan 2021
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Hi all,
I keep running into the error while I am specifying coefficients, namely c, a, and f, and the problem is I do not know why.
It would be very much appreciated if somebody kindly pointed me into the right direction.
- Below is my code:
Mypde = createpde(1);
geometryFromEdges(Mypde, dl);
mesh = generateMesh(Mypde, 'Hmax', 1e-6);
-----------------------
function amatrix = acoeffunction(region,state)
%Given
gv=-2.7460e-6;
I_tkns=7e-8;
F=9.6485e4;
%Now define variables
dP = @(state.u) 30*(state.u^4)-60*(state.u)^3+30*(state.u)^2;
E_chem = gv*dP;
E_over = -E_chem/F;
ED_rate = -I_tkns*E_over;
%Build a matrix for the a coefficient.
n1=2; %length of the vector, representing coefficients
nr = numel(region.x*region.y) %number of columns, region x and y are multiplied because it is a 2D problem.
amatrix = zeros(n1,nr); %allocate a
amatrix(1,:) = ED_rate*V_li*state.ux/state.u
amatrix(2,:) = ED_rate*V_li*state.uy/state.u
- In order for me to test whether the function is correct, I simply put a constant for all other coefficients, and the handle function for a indicated above.
specifyCoefficients(Mypde, 'm', 0, 'd', 1, 'c', 1, 'a', @acoeffunction, 'f', 1)
- The error I am getting is shown below:
Error using pde.CoefficientAssignment/checkCoefFcnHdlArgCounts (line
500)
Function specifying a coefficient must accept two
input arguments and return one output argument.
Error in pde.CoefficientAssignment/checkFcnHdlArgCounts (line 273)
self.checkCoefFcnHdlArgCounts(self.f, systemsize, ndims);
Error in pde.CoefficientAssignment (line 105)
obj.checkFcnHdlArgCounts(systemsize, numdims);
Error in pde.PDEModel/specifyCoefficients (line 139)
coef =
pde.CoefficientAssignment(self.EquationCoefficients,argsToPass{:});
Thank you so much in advance.
If you find any other problems in my script, please let me know.
Have a great day.
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Charlotte Rougier on 31 Jan 2020
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Hi, have you managed to solve this? I have the same issue. Thanks!
ADSW121365 on 4 Mar 2020
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Also seeking a solution to this.
Minjun Bae on 5 Mar 2020
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Hi guys,
I was able to solve this problem.
When you specify a handle function for a coefficient value, if your code includes some functions or variables that are not recognized by the system, this error comes up.
Double check if your code has some contents undefined.
For example,
function fmatrix = fcoeffunction(location,state)
fmatrix=zeros(3,nr)
fmatrix(1,:)=0;
fmatrix(2,:)=0;
fmatrix(3,:)=0;
This also will cause the same error because 'nr' has not been defined in the function handle.
Therefore, nr = numel(location.x) has to be defined before you call nr for defininf fmatrix.
MEHDI Heydari on 20 May 2020
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Hello Minjun,
I did the same steps as you state, but still getting the same error.
I really appriciate if you can comment on my code below.
%c coefficient Matrix
function cMatrix=cCoeff(location, state)
s=0.000610655417342708;
n1=6;
n2=numel(location.x);
cMatrix=zerose(n1,n2);
cMatrix(1,:)= s^2*45337.*exp(-3887./state.u(2,:))/3600;
cMatrix(3,:)=cMatrix(1,:);
cMatrix(4,:)=0.0004*(state.u(1,:)./(1+state.u(1,:))).^2-0.0066*...
(state.u(1,:)./(1+state.u(1,:)))+0.2224;
end
Ravi Kumar on 20 May 2020
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You seem to have a typo in assiging zeros, zerose(n1,n2) must be zeros(n1,n2).
MEHDI Heydari on 26 Jun 2020
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Thanks so much for your attention.
You are right! It works after the correction
mar tav on 10 Jan 2021
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Dear MEHDI Heydari
would you please guide me? I have the same problem as you, but my function is
function [cmatrix] = ccoeffunction(location, B_HMM)
n1 = 4;
nr = numel(location.x);
cmatrix = zeros(n1,nr);
cmatrix(1,:) = B_HMM(1,:);
cmatrix(2,:) = B_HMM(2,:);
cmatrix(3,:) = B_HMM(3,:);
cmatrix(4,:) = B_HMM(4,:);
end
I want to assign the B_HMM matrix as the c coefficient.
Ravi Kumar on 19 Jan 2021
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The ccoeffunction should take two argument, location, state. You are using second argument to pass additional arguments. You can pass additional argument using a wrapper.
In your main scrtip:
B_HMM = ...
ccoefWrapper = @(location, state) ccoeffunction(location, state, B_HMM)
specifyCoefficients(model,'m',...,'c', ccoefWrapper,'f',...)
Then write the function:
function [cmatrix] = ccoeffunction(location, state,B_HMM)
n1 = 4;
nr = numel(location.x);
cmatrix = zeros(n1,nr);
cmatrix(1,:) = B_HMM(1,:);
cmatrix(2,:) = B_HMM(2,:);
cmatrix(3,:) = B_HMM(3,:);
cmatrix(4,:) = B_HMM(4,:);
end
You need to fillin appropriately for ... in the example I have shown above.
Regards,
Ravi
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Answers (1)
Jothi Saravanan on 12 Nov 2020
Open in MATLAB Online
Hi, I am getting the same error. Can someone say what is the mistake I made?
clc; tic; % Clears the screen
clear all;
e=0.5;
mu=0.00689;
V=265.988178;
omega=1047.197;
C=0.0000508;
R=0.508/2;
phi=45;
L=0.127;
%v=12*mu/h^3;
phi=45;
model = createpde();
rect1 = [3,
4,
-1,
1,
1,
-1,
0.3,
0.3,
-0.3,
-0.3];
r=decsg(rect1);
geometryFromEdges(model,r);
applyBoundaryCondition(model,'dirichlet','Edge',1:4,'u',1*10^5);
specifyCoefficients(model,'m',0,...
'd',0,...
'c',1,...
'a',0,...
'f',@fcoeffunction);
generateMesh(model,'Hmax',0.083);
results = solvepde(model);
p= results.NodalSolution;
function f = fcoeffunction(location,state)
N = 1; % Number of equations
nr = length(location.x); % Number of columns
f = zeros(1,nr); % Allocate f
dh=-e*cosd(phi)*sind(location.x+phi)+e*sind(phi)*cosd(location.x+phi);
dt=0.1*omega(e*cosd(phi)*cosd(location.x+phi)+e*sind(phi)*sind(location.x+phi);
o=location.y^2-(L^2/4);
h=C+e*cosd(location.x);
r=(omega*dh+2*dt);
f(1,:)=3*mu*r*o/h^3;
end
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MEHDI Heydari on 12 Nov 2020
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Hi,
There are some errors in your fcoeffunction. Creat new function save it with the name fcoeffunction and then it will run!
function f = fcoeffunction(location,~)
eA=0.5;
mu=0.00689;
omega=1047.197;
C=0.0000508;
L=0.127;
%v=12*mu/h^3;
phi=45;
nr = length(location.x); % Number of columns
f = zeros(1,nr); % Allocate f
dh=-eA*cosd(phi)*sind(location.x+phi)+eA*sind(phi)*cosd(location.x+phi);
dt=0.1*omega*eA*cosd(phi)*cosd(location.x+phi)+eA*sind(phi)*sind(location.x+phi);
o=location.y.^2-(L^2/4);
h=C+eA*cosd(location.x);
r=(omega*dh+2*dt);
f(1,:)=3*mu*r.*o./(h.^3);
end
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