Problems with mldivide,\

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Aj
Aj 2019-10-29
评论： Walter Roberson 2019-10-29
Hello guys,
i have a A*x= B equation and filled my matrices with random numbers.
I used \ to get the results for x.
But when i use the calculated x to multiplicate with A, the result should be the matrix of B. In B and C are different matrices, which i dont understand.
Do i have any mistakes here?
A=rand(183,4);
B=rand(183,1);
x=A\B;
C=A*x;

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Walter Roberson
Walter Roberson 2019-10-29
Your system is over-determined. mldivide is going to do a least-squared fitting. The reconstruction should not be expected to be the same as the original data (not unless the original data can be explained in 4 or fewer linear terms.)
  2 个评论
Aj
Aj 2019-10-29
Thanks for the answer!
How can i fix this? Is there an alternative to mldivide?
Walter Roberson
Walter Roberson 2019-10-29
You cannot fix this. You are asking to explain 183 or more independent values with only 4 coefficients.

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