Solve large system of equations with error "Matrix is close to singular or badly scaled"

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Fernando 2017-4-7

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https://ww2.mathworks.cn/matlabcentral/answers/334238-solve-large-system-of-equations-with-error-matrix-is-close-to-singular-or-badly-scaled

评论： Fernando 2017-4-13

Dear all, I am trying to solve a problem in electromagnetism, due to the units in my equations I have coefficients with very small numbers. My program generates a system of equations which is 1377x1377. I have verified the results of the coefficient that go into the system by hand and they are all right. I thought matlab wouldn't have problems solving this kind of problem as this sytem of equation shouldn't be large compared to other kind of problems but it doesn't seem to be the case. The coefficients in my equation range from ~1.2e-10 to 2.2e-12.

I know the results are incorrect because the values I am obtaining are several orders of magnitude above of what I would expect to see and also some of the values are negative where I would expect so see a positive value. I tried to solve the problem with the default linsolve(A/b) and div(A/b).... any recommendations to try to solve my system in another way would be appreciated.