Pressure fluctuations

From: Ay■e Ízlem Sezerman (asezerman_at_su.sabanciuniv.edu)
Date: Fri Nov 30 2007 - 10:50:32 CST

Hello,
I am running a NPT simulation and usingNosÚ-Hoover Langevin piston .
And my cell basiis vectors and the cocntant pressure control parameters
in my conf file are as follows:

# Periodic Boundary Conditions
cellBasisVector1 48 0. 0.
cellBasisVector2 0. 45 0.
cellBasisVector3 0. 0 54
cellOrigin 0.73 22.08 19.69

langevinPiston yes
langevinPistonTarget 1.01325 ;# in bar -> 1 atm
langevinPistonPeriod 100.
langevinPistonDecay 50.
langevinPistonTemp $temperature

I noticed that the PressAvg values fluctuates between negative and
positive values. (some part of the log file attached below). Does anyone
have an idea about the reason for this fluctuation and what can be done
to avoid this fluctuation.
Thanks for your help and time.

Ozlem

PRESSAVG: 1869000 76.6202 -147.16 14.9218 -147.16 -29.9845 0.339268
14.9218 0.339268 -32.1724
GPRESSAVG: 1869000 76.8286 -147.345 15.6683 -147.489 -30.8324 1.65845
14.6006 0.611249 -31.3294
ENERGY: 1869000 237.0592 680.6608 574.9827
33.8622 -44065.0036 3910.7420 0.0000
0.0000 3227.7406 -35399.9561 150.5978
-35384.9567 -35384.9174 150.3136 175.8987
229.9346 93549.8175 4.8211 4.8889

WRITING COORDINATES TO DCD FILE AT STEP 1869000
PRESSURE: 1870000 24.1278 -180.047 -254.666 -180.047 340.346 -228.999
-254.666 -228.999 455.44
GPRESSURE: 1870000 117.852 -167.254 -336.024 -220.417 425.33 -95.885
-161.575 -500.637 403.696
PRESSAVG: 1870000 0.0523777 -164.528 25.7712 -164.528 23.5615 72.9395
25.7712 72.9395 -23.6654
GPRESSAVG: 1870000 -0.649415 -165.241 25.8191 -164.475 23.7788 71.7497
26.8925 72.5491 -24.0225
TIMING: 1870000 CPU: 105755, 0.0580177/step Wall: 110932,
0.0602249/step, 52.5295 hours remaining, 14356 kB of memory in use.
ETITLE: TS BOND ANGLE DIHED
IMPRP ELECT VDW BOUNDARY
MISC KINETIC TOTAL TEMP
TOTAL2 TOTAL3 TEMPAVG PRESSURE
GPRESSURE VOLUME PRESSAVG GPRESSAVG

ENERGY: 1870000 224.5976 703.0702 569.8226
39.9984 -43927.2098 3826.8333 0.0000
0.0000 3182.6699 -35380.2177 148.4950
-35364.9750 -35365.3431 149.2740 273.3046
315.6259 93871.6244 -0.0172 -0.2977

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1870000
WRITING COORDINATES TO DCD FILE AT STEP 1870000
WRITING COORDINATES TO RESTART FILE AT STEP 1870000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1870000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.93036 MAX 3.04791 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.93036 MAX 2.96275 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1871000 -356.819 56.2657 -18.2488 56.2657 -51.9287 76.4039
-18.2488 76.4039 -410.579
GPRESSURE: 1871000 -320.337 235.879 -90.7807 66.6421 -55.8698 -43.8688
21.2278 72.0555 -292.276
PRESSAVG: 1871000 23.2382 -110.917 33.6388 -110.917 62.9 127.97 33.6388
127.97 -79.4046
GPRESSAVG: 1871000 23.1552 -110.973 33.6234 -110.981 62.5948 127.323
33.0791 128.835 -79.2371
ENERGY: 1871000 245.1829 689.8446 567.6882
39.7471 -43973.4139 3794.0841 0.0000
0.0000 3195.5856 -35441.2814 149.0976
-35426.7493 -35426.1834 149.7437 -273.1088
-222.8274 93920.1096 2.2445 2.1710

WRITING COORDINATES TO DCD FILE AT STEP 1871000
PRESSURE: 1872000 -35.5752 88.9889 -248.358 88.9889 -390.483 -43.7913
-248.358 -43.7913 -887.631
GPRESSURE: 1872000 -114.087 242.529 -64.2556 3.28006 -284.256 -3.41227
-461.101 -143.032 -819.19
PRESSAVG: 1872000 107.696 -98.0116 -4.33097 -98.0116 17.6097 152.704
-4.33097 152.704 -135.257
GPRESSAVG: 1872000 107.121 -98.7384 -5.1255 -98.4621 17.9441 153.464
-4.80868 152.541 -135.436
ENERGY: 1872000 259.6824 679.6077 570.3944
37.6594 -43871.6678 3741.5292 0.0000
0.0000 3182.6119 -35400.1828 148.4923
-35385.1936 -35385.9991 148.2498 -437.8963
-405.8441 93970.5940 -3.3172 -3.4570

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1872000
WRITING COORDINATES TO DCD FILE AT STEP 1872000
WRITING COORDINATES TO RESTART FILE AT STEP 1872000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1872000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.90726 MAX 2.98749 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.90726 MAX 2.96384 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1873000 -115.798 228.072 -132.67 228.072 -317.847 292.634
-132.67 292.634 -526.056
GPRESSURE: 1873000 -75.0895 94.1186 -357.685 343.155 -295.633 163.889
-164.667 303.633 -472.875
PRESSAVG: 1873000 115.042 -42.2528 22.1889 -42.2528 -24.4305 103.476
22.1889 103.476 -93.3364
GPRESSAVG: 1873000 115.393 -42.6059 23.2023 -42.5014 -24.5236 103.049
22.711 103.258 -92.7272
ENERGY: 1873000 247.4253 734.2501 571.1967
37.5962 -44031.8434 3869.6102 0.0000
0.0000 3198.1565 -35373.6085 149.2175
-35358.3466 -35358.8855 149.0654 -319.9004
-281.1992 93889.6854 -0.9082 -0.6194

WRITING COORDINATES TO DCD FILE AT STEP 1873000
PRESSURE: 1874000 589.872 67.8347 -100.388 67.8347 -326.999 288.935
-100.388 288.935 545.676
GPRESSURE: 1874000 642.538 245.606 -100.74 -206.509 -336.972 362.672
-6.84558 163.555 578.973
PRESSAVG: 1874000 88.7058 -83.6877 34.1933 -83.6877 -13.6402 161.649
34.1933 161.649 -65.689
GPRESSAVG: 1874000 88.9783 -83.1729 33.2569 -83.7144 -14.4994 161.462
34.9375 162.221 -66.1575
ENERGY: 1874000 247.2340 702.4011 572.1791
37.2265 -44013.5198 3885.9745 0.0000
0.0000 3230.3424 -35338.1622 150.7192
-35324.3805 -35319.3707 150.1177 269.5162
294.8459 93435.3967 3.1255 2.7738

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1874000
WRITING COORDINATES TO DCD FILE AT STEP 1874000
WRITING COORDINATES TO RESTART FILE AT STEP 1874000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1874000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.91903 MAX 2.98824 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.91903 MAX 2.95246 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1875000 59.2825 -384.645 -34.2689 -384.645 402.37 -90.4227
-34.2689 -90.4227 296.226
GPRESSURE: 1875000 156.326 -372.94 -56.021 -229.559 428.093 90.1725
-238.067 -119.988 323.865
PRESSAVG: 1875000 90.9692 -131.803 39.1927 -131.803 -24.0199 122.579
39.1927 122.579 -62.7053
GPRESSAVG: 1875000 91.3153 -132.35 40.1994 -131.112 -24.236 122.214
38.7907 123.454 -62.8395
ENERGY: 1875000 256.6046 691.0622 570.1243
41.7908 -43954.0969 3851.3329 0.0000
0.0000 3248.5396 -35294.6425 151.5683
-35278.7583 -35281.6626 150.6083 252.6263
302.7616 93667.2910 1.4147 1.4133

WRITING COORDINATES TO DCD FILE AT STEP 1875000
PRESSURE: 1876000 -256.859 -374.873 -200.348 -374.873 -295.671 59.7297
-200.348 59.7297 -333.202
GPRESSURE: 1876000 -245.102 -338.381 -249.374 -358.715 -137.451 -4.46398
-198.739 86.6318 -385.558
PRESSAVG: 1876000 91.9184 -125.408 12.2613 -125.408 -45.2127 88.1209
12.2613 88.1209 -35.5883
GPRESSAVG: 1876000 92.4558 -125.692 12.3646 -125.042 -44.5282 88.4378
12.7319 87.6461 -35.5486
ENERGY: 1876000 251.9766 695.5303 573.4368
41.2895 -43901.0891 3779.4227 0.0000
0.0000 3160.2474 -35399.1858 147.4488
-35383.5128 -35386.8440 150.1670 -295.2438
-256.0369 93765.3551 3.7058 4.1263

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1876000
WRITING COORDINATES TO DCD FILE AT STEP 1876000
WRITING COORDINATES TO RESTART FILE AT STEP 1876000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1876000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.93932 MAX 3.03681 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.93932 MAX 2.99366 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1877000 -382.57 82.0397 -39.8976 82.0397 -451.774 449.865
-39.8976 449.865 -261.333
GPRESSURE: 1877000 -304.44 -200.62 -126.483 229.732 -400.773 563.5
69.6013 327.958 -264.794
PRESSAVG: 1877000 93.5066 -104.905 28.9176 -104.905 -33.5867 131.901
28.9176 131.901 -60.7919
GPRESSAVG: 1877000 93.2652 -105.394 29.0114 -104.142 -33.568 132.616
28.734 132.322 -61.2283
ENERGY: 1877000 252.9688 701.9856 577.3066
44.0068 -43908.5370 3777.7357 0.0000
0.0000 3250.6901 -35303.8435 151.6686
-35289.1491 -35287.9189 150.8919 -365.2258
-323.3355 93888.3377 -0.2907 -0.5104

WRITING COORDINATES TO DCD FILE AT STEP 1877000
PRESSURE: 1878000 475.415 -177.213 -197.931 -177.213 -154.388 362.546
-197.931 362.546 -27.0002
GPRESSURE: 1878000 531.023 -307.66 -231.231 -28.5876 -178.873 306.204
-388.57 365.335 66.431
PRESSAVG: 1878000 76.142 -95.4706 21.6164 -95.4706 0.6368 197.878
21.6164 197.878 -82.9898
GPRESSAVG: 1878000 76.4051 -95.2059 21.7644 -96.5016 0.9217 197.409
20.2742 198.962 -83.7261
ENERGY: 1878000 241.5848 700.1645 569.1977
35.0316 -43882.7802 3799.4693 0.0000
0.0000 3290.9259 -35246.4063 153.5459
-35232.2567 -35228.2063 151.0456 98.0088
139.5270 93683.5863 -2.0703 -2.1331

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1878000
WRITING COORDINATES TO DCD FILE AT STEP 1878000
WRITING COORDINATES TO RESTART FILE AT STEP 1878000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1878000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.92494 MAX 3.02005 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.92494 MAX 2.96047 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1879000 -17.4663 -315.883 260.531 -315.883 302.46 349.321
260.531 349.321 217.371
GPRESSURE: 1879000 91.5974 -310.883 230.861 -339.465 233.295 310.738
328.052 257.805 285.499
PRESSAVG: 1879000 129.508 -98.1876 57.3344 -98.1876 -51.4367 207.153
57.3344 207.153 -79.1764
GPRESSAVG: 1879000 129.403 -97.3586 57.0845 -97.895 -51.6486 207.787
58.3714 206.681 -79.0875
ENERGY: 1879000 244.7713 683.1487 573.5299
39.7835 -44080.2486 3910.2172 0.0000
0.0000 3232.0175 -35396.7803 150.7974
-35381.8448 -35382.3297 151.2411 167.4547
203.4637 93698.2574 -0.3685 -0.4443

WRITING COORDINATES TO DCD FILE AT STEP 1879000
PRESSURE: 1880000 441.291 -394.1 -25.0597 -394.1 -121.68 561.315
-25.0597 561.315 -394.148
GPRESSURE: 1880000 477.726 -495.063 -15.7252 -425.902 -147.696 408.758
74.298 535.702 -277.419
PRESSAVG: 1880000 40.8499 -46.7435 65.9712 -46.7435 -3.93305 120.384
65.9712 120.384 -28.039
GPRESSAVG: 1880000 41.125 -46.2217 65.0595 -47.6776 -4.43098 119.486
65.9497 120.725 -27.7272
TIMING: 1880000 CPU: 106322, 0.0566934/step Wall: 111525,
0.0593736/step, 51.6221 hours remaining, 14356 kB of memory in use.
ETITLE: TS BOND ANGLE DIHED
IMPRP ELECT VDW BOUNDARY
MISC KINETIC TOTAL TEMP
TOTAL2 TOTAL3 TEMPAVG PRESSURE
GPRESSURE VOLUME PRESSAVG GPRESSAVG

ENERGY: 1880000 256.5704 687.5371 562.0515
36.3225 -44053.7921 3910.3020 0.0000
0.0000 3160.6764 -35440.3321 147.4688
-35425.3307 -35426.1938 149.2872 -24.8457
17.5368 93784.3183 2.9593 2.9889

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1880000
WRITING COORDINATES TO DCD FILE AT STEP 1880000
WRITING COORDINATES TO RESTART FILE AT STEP 1880000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1880000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.9124 MAX 2.97936 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.9124 MAX 2.96914 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1881000 -361.821 17.573 -280.797 17.573 -190.096 602.316
-280.797 602.316 -609.895
GPRESSURE: 1881000 -312.613 -4.90826 -352.659 60.0544 -274.289 516.073
-231.383 564.026 -450.172
PRESSAVG: 1881000 4.33381 -67.8467 37.889 -67.8467 14.4642 114.735
37.889 114.735 -20.3653
GPRESSAVG: 1881000 4.4706 -67.8633 38.3136 -66.8679 14.0917 115.902
38.3173 114.489 -20.1305
ENERGY: 1881000 254.2454 704.0720 578.7957
41.0223 -43881.4646 3753.1715 0.0000
0.0000 3201.7421 -35348.4155 149.3848
-35332.5572 -35336.0905 149.9902 -387.2710
-345.6917 93862.4071 -0.5224 -0.5227

WRITING COORDINATES TO DCD FILE AT STEP 1881000
PRESSURE: 1882000 505.855 -42.5617 -162.632 -42.5617 364.419 -129.945
-162.632 -129.945 504.27
GPRESSURE: 1882000 619.176 -56.9102 -295.023 -157.674 437.599 -77.5162
-94.5557 -140.808 448.298
PRESSAVG: 1882000 23.563 -71.8855 -3.89006 -71.8855 55.7455 166.708
-3.89006 166.708 -82.8279
GPRESSAVG: 1882000 23.8957 -72.2945 -3.86525 -71.2253 55.8913 166.898
-5.64875 166.884 -83.8563
ENERGY: 1882000 247.0403 693.6860 590.1168
40.8012 -44009.8563 3889.4225 0.0000
0.0000 3185.1106 -35363.6789 148.6088
-35349.3200 -35346.3866 150.2951 458.1816
501.6910 93531.8010 -1.1732 -1.3564

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1882000
WRITING COORDINATES TO DCD FILE AT STEP 1882000
WRITING COORDINATES TO RESTART FILE AT STEP 1882000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1882000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.90843 MAX 2.98858 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.90843 MAX 2.96562 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1883000 -526.315 -147.044 -121.627 -147.044 -387.927 75.1342
-121.627 75.1342 -33.0853
GPRESSURE: 1883000 -454.354 -16.4841 -111.456 -266.652 -185.608 85.7724
176.613 82.677 -154.539
PRESSAVG: 1883000 9.03657 -93.6366 47.437 -93.6366 13.7125 101.502
47.437 101.502 -32.7824
GPRESSAVG: 1883000 9.86898 -93.1486 46.9167 -94.5418 13.5191 101.644
48.4481 101.087 -33.5682
ENERGY: 1883000 260.0950 708.0191 575.0313
37.1201 -43959.0145 3839.5512 0.0000
0.0000 3177.6914 -35361.5064 148.2627
-35346.7841 -35345.5810 150.0107 -315.7756
-264.8336 93939.5493 -3.3445 -3.3934

WRITING COORDINATES TO DCD FILE AT STEP 1883000
PRESSURE: 1884000 -10.613 -171.89 -56.8383 -171.89 -428.672 115.776
-56.8383 115.776 355.073
GPRESSURE: 1884000 39.0488 -249.625 -150.661 -155.622 -228.37 256.119
83.5652 88.0896 200.165
PRESSAVG: 1884000 -17.7639 -42.1044 -24.279 -42.1044 -51.4429 110.462
-24.279 110.462 63.1962
GPRESSAVG: 1884000 -17.248 -42.1704 -24.1299 -40.1499 -52.2729 110.49
-25.8417 110.989 62.8091
ENERGY: 1884000 261.0082 721.4908 575.1194
39.4688 -44129.6063 3878.8251 0.0000
0.0000 3212.3090 -35441.3850 149.8778
-35426.3413 -35426.3340 149.0417 -28.0706
3.6145 93444.9630 -2.0035 -2.2373

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1884000
WRITING COORDINATES TO DCD FILE AT STEP 1884000
WRITING COORDINATES TO RESTART FILE AT STEP 1884000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1884000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.91953 MAX 2.96668 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.91953 MAX 2.96668 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1885000 65.2877 -192.153 173.237 -192.153 399.301 -24.0075
173.237 -24.0075 147.5
GPRESSURE: 1885000 296.948 34.2461 61.8756 -280.555 318.706 -122.839
184.964 -143.817 144.466
PRESSAVG: 1885000 -6.8233 -55.243 98.3687 -55.243 18.5923 188.193
98.3687 188.193 -26.8433
GPRESSAVG: 1885000 -6.90405 -54.9845 98.3126 -55.3935 19.6425 188.069
99.5897 187.597 -26.5634
ENERGY: 1885000 245.7468 737.9904 558.3091
37.8094 -44037.5022 3884.6273 0.0000
0.0000 3214.1808 -35358.8384 149.9652
-35343.1009 -35344.9946 148.8801 204.0296
253.3733 93503.9003 -5.0248 -4.6083

WRITING COORDINATES TO DCD FILE AT STEP 1885000
PRESSURE: 1886000 595.748 -58.6408 12.7695 -58.6408 390.343 78.5423
12.7695 78.5423 98.0188
GPRESSURE: 1886000 640.542 -29.6613 -260.623 -127.353 401.412 214.355
103.157 34.6343 137.722
PRESSAVG: 1886000 29.0458 -105.945 70.5066 -105.945 -49.4292 187.036
70.5066 187.036 18.0426
GPRESSAVG: 1886000 28.5196 -106.491 69.6923 -105.893 -49.5042 187.871
71.4241 187.741 18.5388
ENERGY: 1886000 248.4407 687.3692 566.1943
33.5223 -44039.8440 3901.8130 0.0000
0.0000 3233.6472 -35368.8573 150.8734
-35353.9607 -35353.1885 150.1280 361.3700
393.2254 93568.4640 -0.7803 -0.8153

WRITING EXTENDED SYSTEM TO RESTART FILE AT STEP 1886000
WRITING COORDINATES TO DCD FILE AT STEP 1886000
WRITING COORDINATES TO RESTART FILE AT STEP 1886000
FINISHED WRITING RESTART COORDINATES
WRITING VELOCITIES TO RESTART FILE AT STEP 1886000
FINISHED WRITING RESTART VELOCITIES
LDB: LOAD: AVG 2.94945 MAX 3.01572 MSGS: TOTAL 68 MAXC 10 MAXP 7 None
LDB: LOAD: AVG 2.94945 MAX 3.00166 MSGS: TOTAL 68 MAXC 10 MAXP 7 Refine
PRESSURE: 1887000 427.632 13.0294 -46.185 13.0294 -448.228 52.7726
-46.185 52.7726 -189.538
GPRESSURE: 1887000 407.611 -46.0126 -163.558 0.298585 -446.621 69.9901
-117.907 35.158 -39.2177
PRESSAVG: 1887000 25.7011 -81.2418 19.6352 -81.2418 -20.5871 193.792
19.6352 193.792 -2.34433
GPRESSAVG: 1887000 25.2535 -81.8041 19.9438 -81.0239 -20.1784 193.744
18.7887 193.183 -2.40594
ENERGY: 1887000 259.3559 717.7991 569.7005
40.1478 -43968.2131 3816.0398 0.0000
0.0000 3188.2910 -35376.8790 148.7572
-35359.7973 -35366.3342 149.6740 -70.0447
-26.0760 93734.4649 0.9232 0.8897

WRITING COORDINATES TO DCD FILE AT STEP 1887000

This archive was generated by hypermail 2.1.6 : Wed Feb 29 2012 - 15:45:38 CST