error about pppm

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1

Hi,everyone,

I am using the pair_style buck/coul/long and kspace_style pppm. A error occured when I raise the temperature of the sample.

PPPM initialization …
G vector = 0.287497
grid = 100 96 60
stencil order = 5
RMS precision = 8.01474e-05
brick FFT buffer size/proc = 117920 76800 44220
Setting up run …
Memory usage per processor = 70.133 Mbytes
Step Temp Press PotEng KinEng TotEng Volume mypress[ mypress[ mypress[ mypress[ mypress[ mypress[
0 300.01562 -1120.6545 -1687179.2 4764.092 -1682415.1 1685814 -956.44707 -1290.228 -1115.2883 1519.8702 -646.7599 -4521.8512
10000 401.70476 -79.911375 -1687173.3 6378.8625 -1680794.5 1685814 83.232404 -240.88485 -82.081682 1508.9376 -664.7697 -4506.1327
20000 499.37451 1037.1055 -1687103.3 7929.8073 -1679173.5 1685814 1194.9208 888.89299 1027.5028 1487.7729 -684.30684 -4491.3764
30000 589.33391 2294.169 -1686910.4 9358.3157 -1677552.1 1685814 2439.676 2162.6424 2280.1885 1456.7391 -705.02546 -4478.9303
40000 669.02548 3716.7035 -1686553.9 10623.776 -1675930.1 1685814 3842.1686 3604.1939 3703.748 1415.9758 -724.89676 -4469.3982
50000 737.45597 5279.7464 -1686017.9 11710.417 -1674307.5 1685814 5376.5741 5186.2916 5276.3734 1367.278 -741.26255 -4463.8105
60000 795.36322 6908.24 -1685314 12629.954 -1672684 1685814 6967.5244 6831.5153 6925.6802 1312.1531 -751.37489 -4462.6538
70000 845.03839 8488.2888 -1684478 13418.77 -1671059.2 1685814 8500.836 8423.3987 8540.6317 1254.2838 -752.47931 -4465.2112
80000 889.81221 9886.8415 -1683562 14129.755 -1669432.2 1685814 9843.2774 9827.6795 9989.5677 1197.8225 -743.64969 -4468.6245
90000 933.22827 10965.318 -1682623.8 14819.179 -1667804.7 1685814 10847.629 10908.694 11139.632 1146.4326 -721.86728 -4470.1026
100000 979.99812 11517.674 -1681741 15561.86 -1666179.1 1685814 11146.399 11550.019 11856.604 1126.8174 -615.90871 -4475.5257
ERROR: Out of range atoms - cannot compute PPPM

2

Hi,everyone,

I am using the pair_style buck/coul/long and kspace_style pppm. A error
occured when I raise the temperature of the sample.

have you equilibrated your structure before raising the temperature?

axel.

3

yes. And it has no problems.

2011/3/30 Axel Kohlmeyer <[email protected]>

4

yes. And it has no problems.

and you are starting from that equilibrated structure?

your potential energy is raising very fast.
perhaps your equilibration was stuck in a
metastable state and with the raising temperature
is dropping into a different minimum.

try raising the temperature _much_ slower and
see what happens.

is the potential tested to be suitable for high temperature?

axel.

5

Yes. But the potential was test under high pressure and not tested under the high temperature.

2011/3/30 Axel Kohlmeyer <[email protected]>

6

Yes. But the potential was test under high pressure and not tested under the
high temperature.

i would re-run the calculation with a slower increase of temperature
(at lest by a factor of 10, better 20, 50 or even 100) and then carefully
monitor what is going on through visualization of the trajectory.

if you have a change in overall structure, a _lot_ of potential energy
may be released quickly, and that would need to be dissipated.

there is no simple rule for these kind of things. you have to monitor
what is going on and act using common sense.

cheers,
      axel.

7

Are you checking for the need to reneighbor every step? If atoms
move too far before reneighboring, you get that error.

Steve