Non-constant Numerical coefficients (m,d,a,c,f)

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Sattik Basu 2022-5-12

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https://ww2.mathworks.cn/matlabcentral/answers/1718025-non-constant-numerical-coefficients-m-d-a-c-f

回答： Avni Agrawal 2023-10-5

The pdetoolbox is equipped to solve a PDE with non-constant coefficients. However, from what i read in the manuals, the coefficients need to be a function of location (x,y) or state (u,ux,uy,t). However, if I know the coefficient distribution across the entire geometry (ie, i have a matrix of for a rectangular domain), how can I input them as coefficients to the toolbox?

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Prakhar Sharma 2022-6-14

I have the same question

Torsten 2022-6-14

在 MATLAB Online 中打开

As a function handle:

f = @(x,y) interp2(X,Y,Coefficient,x,y)

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Answer 1

Avni Agrawal 2023-10-5

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https://ww2.mathworks.cn/matlabcentral/answers/1718025-non-constant-numerical-coefficients-m-d-a-c-f#answer_1326554

在 MATLAB Online 中打开

I understand that you are trying to find how to pass input arguments to function handle for non-constant numerical co-efficients.

The function must accept two input arguments, location and state. The solvers automatically compute and populate the data in the “location” and “state” structure arrays and pass this data to your function. Specify the PDE coefficients using the function you wrote.

This can be understood by the following example :

specifyCoefficients(model,"m",0,"d",0,"c",1,"a",0,"f",@fcoefffunc); 
function fcoeff = fcoefffunc(location,state) 
    fcoeff = location.x.^2.*sin(location.y); 
    scatter(location.x,location.y,".","black"); 
    hold on 
end 