the error here in equalization an ordinary variable in symbolic the error in E and says:" Conversion to double from sym is not possible." wt can ii do???

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SAM alimostafa 2011-4-4

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/4732-the-error-here-in-equalization-an-ordinary-variable-in-symbolic-the-error-in-e-and-says-conversion

syms x;

 syms y;
rt=[x y];
xloc=[1 2 4 5];
yloc=[23 45 67 44];
N=4;

noOfratios=6;

E=[ones(1,1),ones(1,1)]

%s=5*ones(1,length(N));

for i=1:N

di=rt-[xloc(i),yloc(i)]

E(i,1)=1./(abs(di).^2);

end

for i = 1:noOfratios

    j = setdiff(1:noOfratios,i);
    k(i,j)=E(i)/E(j);

end

for i = 1:noOfratios

j = setdiff(1:noOfratios,i);

c(i,j)=r(i,2)-k(i,j).*r(j,2);

di=[xloc(i)-xloc(j),yloc(i)-yloc(j)]

p(i,j)=(k(i,j).*(abs(di)))./(1-k(i,j).^2)

end

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回答（1 个）

Walter Roberson 2011-4-4

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https://ww2.mathworks.cn/matlabcentral/answers/4732-the-error-here-in-equalization-an-ordinary-variable-in-symbolic-the-error-in-e-and-says-conversion#answer_6570

Umm, exactly which line does it say it on?

And where did you get the idea that the single symbolic variable "r", which is never assigned a value, could be indexed at (i,2) and (j,2) at the Matlab level?

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Walter Roberson 2011-4-4

Is there a point in doing the abs() before doing the .^2 ? Are you expecting imaginary values or only real values?

SAM alimostafa 2011-4-4

no points i want to ignore negative values and only real values is expecting

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