Error returned in Eigs Function " Undefined operator '.*' "

Hello !

I am working on the resolution of Orr-Sommerfeld equation and I used the code readable at https://www.mathworks.com/matlabcentral/mlc-downloads/downloads/submissions/23972/versions/22/previews/chebfun/examples/ode-eig/html/OrrSommerfeld.html .

However, it returns error. I ran line by line until finding the problem line, it is this one :

% e = eigs(A,B,50,'LR');

Which returns a triple error :

% Undefined operator '.*' for input arguments of type 'operatorBlock'.
%
% Error in @(x,u)(diff(u,4)-2.*diff(u,2)+u)./Re-2i.*u-1i.*diag(1-x.^2).*(diff(u,2)-u)
%
% Error in chebop/feval (line 190)
%    out = N.op(x, u);
%
% Error in chebop/linearize (line 150)
%         Nu = feval(N, x, u{:});
%
% Error in chebop/eigs (line 59)
% [L, ~, isLinear, u0] = linearize(N, N.init, [], linCheck);

Does anyone has an idea for the origin of these errors ?

Thanks.

Wulfran Deberdt, last semester's project at UC Berkeley

[Walter Roberson]

Make sure you get the current version of the code from https://github.com/chebfun/chebfun

Answer 1

[Andrew Knyazev]

Looks like a bug in chebfun - just make this comment at https://www.mathworks.com/matlabcentral/fileexchange/47023-chebfun-current-version for the chebfun authors to see and react.

Answer 2

[Wulfran Deberdt]

Thank you but I found the problem, just have to withdraw the built-in function "diag"