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QuantumATK => General Questions and Answers => Topic started by: Jyotirmoy Deb on January 21, 2020, 17:08

Title: Phonon transmission calculations error
Post by: Jyotirmoy Deb on January 21, 2020, 17:08

I have executed one phonon transmission calculations but unfortunately the calculation encountered an error showing an error message saying  "DynamicalMatrix calculations often require a tighter tolerance than the default".

Title: Re: Phonon transmission calculations error
Post by: Petr Khomyakov on January 22, 2020, 09:33

It is a warning, not an error. Using too low tolerance for total energy calculations might however give rise to large errors in Dynamical matrix, and your tolerance parameter is indeed pretty large, 10^-3, which is even larger than default value of 10^-4. I would set it to 10^-5.  In fact, one should check if Dynamical matrix does not significantly change when going, e.g., from tolerance of 10^-3 to 10^-4. If it does, one may even consider using 10^-5 to see if tolerance 10^-4 gives you converged Dynamical matrix.