[gpaw-users] GPAW PW crashes if ecut is too high

[Rasmus Karlsson]

Hi!
I just tried starting a PW calculation for relaxation of a unit cell of 
CmC2_1 space group. However, GPAW immediately crashes with
../gpaw/wavefunctions/pw.py", line 37, in __init__
     assert ((gd.h_cv**2).sum(1) <= 0.5 * pi**2 / ecut).all()

If running through with pdb, (gd.h_cv**2).sum(1) is
array([ 0.05550866,  0.25919729,  0.25919729])
and
0.5*pi**2/ecut is
0.22380475860123122
Obviously, the second and third item in the array is too big. Reducing 
the cutoff from 600 eV to 500 eV makes it work. This is somewhat strange.

gd.h_cv is
array([[  2.35602765e-01,   0.00000000e+00,   0.00000000e+00],
        [  3.11742550e-17,   5.09114220e-01,   0.00000000e+00],
        [  3.11742550e-17,  -4.50356897e-01,   2.37436210e-01]])

Can anyone comment on what is going on? Am I doing something wrong, or 
is GPAW behaving strangely?

The calculation was run with v. 0.9.1.10258

Thanks,
Rasmus

-- 
Rasmus Karlsson, PhD student
Applied Electrochemistry
School of Chemical Science and Engineering
KTH Royal Institute of Technology
SE-100 44 Stockholm
Sweden