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<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;">Hi All,</div>
<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;"> </div>
<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;">I am experiencing that the success in scf cycle depends on the number of processes used in mpirun. That is, for example, for a given scf input when I use "mpirun -np <strong>2</strong> pw.x < input.in",</div>
<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;">it gives the converged result in a reasonable number of iteration; but, on the other hand, if I instead use "mpirun -np <strong>8</strong> pw.x < input.in", the system does not converge numerically.</div>
<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;">First I thought it is somehow a problem of numerical error accumulation. So, I used in compilation of QE the FFTW3 as prescribed in the manual. And even used "-lfftw3l" (long-double) to cure this problem, but some other numerical problems happened in vc-relax job.</div>
<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;"> </div>
<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;">I would appreciate if anybody helps to understand the roots of this dependency and how to control it.</div>
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<div style="font-size: 16px; font-family: Tahoma; color: rgb(0, 0, 0); font-weight: 400; font-style: normal; background: rgba(0, 0, 0, 0) none repeat scroll 0% 0%;">Bests,</div>
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<div style="font-family: Tahoma; color: rgb(0, 0, 0); font-size: 16px; font-weight: 400; font-style: normal;">Mahmoud Payami</div>
<div style="font-family: Tahoma; color: rgb(0, 0, 0); font-size: 16px; font-weight: 400; font-style: normal;">NSTRI, AEOI, Tehran, Iran</div>
<div style="font-family: Tahoma; color: rgb(0, 0, 0); font-size: 16px; font-weight: 400; font-style: normal;"> </div>
<div style="font-family: Tahoma; color: rgb(0, 0, 0); font-size: 16px; font-weight: 400; font-style: normal;">Email: mpayami@aeoi.org.ir</div>
<div style="font-family: Tahoma; color: rgb(0, 0, 0); font-size: 16px; font-weight: 400; font-style: normal;">Phone: +98 (0)21 82066504</div>
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