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- run pardiso twice on same matrix = not same result

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apocalx

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09-09-2011
10:23 AM

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run pardiso twice on same matrix = not same result

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Gennady_F_Intel

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09-09-2011
10:00 PM

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I just quickly checked the issue - I 've got the different numbers

x[2] = -0.220519 +j 26.730090

x[2] = -0.333848 +j 26.842847

x[2] = -0.220519 +j 26.730090

x[2] = -0.333848 +j 26.842847

x[2] = -0.220519 +j 26.730090

but the similar unrepeated results.

We will investigate the problem and back soon.

Did you check the condition number of this input?

--Gennady

styc

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09-11-2011
08:02 PM

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EDIT: Well, it is worse than that. The matrix is singular. The last row is all zeros. Changing the bottom right element to 1 produces a matrix with a 2-condition number of 1.8e27.

Konstantin_A_Intel

Employee

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09-11-2011
08:50 PM

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Indeed, if the matrix is singular (or highly ill-conditioned) than the solving process is highly unstable and, generally speaking, the result of computations is unpredictable.

Regards,

Konstantin

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For more complete information about compiler optimizations, see our Optimization Notice.