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Dalklint__Anna

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10-21-2020
07:42 AM

99 Views

Floating divide by zero error in dfeast_scsrgv

Hi,

I am using the FEAST eigenvalue solver to solve a generalized eigenvalue problem with symmetric sparse matrices in Fortran (Compiler: ifort 2020). I store the upper triangular parts of the matrices, i.e. set UPLO = 'U'.

Currently, I receive an error from ifort "forrtl: error (73): floating divide by zero", which is traced back to the dfeast_scsrgv call. I know that the matrices in the generalized eigenvalue problem may contain small values (i.e. values close to zero). So the sparse patterns might contain zero values. Could this be the cause of the error?

I have tried setting fpm(27) = 1 and fpm(28) = 1 to check input matrices, but this is not recognized by the dfeast_scsrgv call (it isn't listed in the output: List of input parameters fpm(1:64)-- if different from default). Is this a known issue?

Thank you,

Anna

1 Reply

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Ronald_G_Intel

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10-21-2020
12:50 PM

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You may want to try the option -no-ftz

this may or may not help. If you think you are in the realm of denormals FTZ could be causing the zeroes.

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