Error with Cheb function

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Chala Kedir 2022-4-9

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https://ww2.mathworks.cn/matlabcentral/answers/1692395-error-with-cheb-function

回答： Bhavana Ravirala 2023-2-15

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Where the ODE is

with boundary condition

y(1)=sin(1)

D = [1/pi*3 ,1];
N = chebop(D); 
N.lbc = [1];
N.rbc = 1 - sin(1);
N.op = @(t,x,y) diff(y,2) + (2/x)*diff(y,1) + (1/(x^4))*y;
[x, y] = N\0;
plot([x, y]);

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Chala Kedir 2022-4-10

编辑：Chala Kedir 2022-4-10

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@Walter Roberson

this is the error message I get

Error using chebop/linearize
Failed to evaluate operator on the initial guess passed (or the one constructed
by CHEBOP). A potential cause might be division by a zero CHEBFUN. Please supply
a valid initial guess via the 'init' field of the CHEBOP.
Error in chebop/solvebvp (line 109)
[L, residual, isLinear] = linearize(N, u0, x);
Error in  \  (line 56)
    [varargout{1:nargout}] = solvebvp(N, rhs, varargin{:});
Error in untitled (line 6)
[x, y] = N\0;

Torsten 2022-4-10

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Are you sure about your D ?

Shouldn't it be

D = [1, 1/3*pi];

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回答（1 个）

Bhavana Ravirala 2023-2-15

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1692395-error-with-cheb-function#answer_1171910

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Hi,

The error you received indicates that the operator fails to evaluate the initial guess. To resolve this error, we can assign the initial guess with the boundary conditions.

N.init = [0; sin(1)];

Hope this helps!!