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problem with dgetrf, LU-decomposion

shapovalov
Beginner
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I want to calculate LU-decomposition of square matrix. I call function dgetrf() but returned result is uncorrect.

double A[100,100]; int Size=100; int *ipiv = new int[100]; int info;
/*...*/
dgetrf(&Size,&Size,A,&Size,ipiv,&info);

I think, matrix A beforedgetrf()must be = P*L*U after dgetrf(), where P can be obtained from ipiv. Please,check my code.

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TimP
Honored Contributor III
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You don't give enough context to test whether your A looks like a Fortran double subscripted array; in general, it will not. You must refer to the reference source code for the interpretation of ipiv. As you don't give anything to check, there are several other points on which you could make mistakes.
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Gennady_F_Intel
Moderator
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Oleg, there are some Lapack examples where you can find how these routines calling the right way.
Please see: exampleslapacksource ...dgeconx.f, dgerfsx.f, dgetrfx.f, dgetrix.f, dgetrsx.f
--Gennady

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