James -
Well, the pmemd simulation clearly blew up. This is most probably related
to your earlier problems with not wrapping the coordinates, but why pmemd is
responding differently, I am not sure. First of all, are you using pmemd in
amber 7 compatibility mode? The reason I ask is that in sander 7 there is a
default vlimit of 10 (I think), as opposed to no default vlimit in sander 6.
Pmemd does not use a vlimit in 6-mode, but mimics sander 7's treatment of
vlimits in 7 mode. I presume that nscm/ntcm are okay, based on COM printout
in the listing below, but the fact you suddenly have significant COM removal
indicates the pmemd simulation is in trouble. I really need to have a look
at all the input files for both these runs, and information or inputs for
earlier phases of the simulation would be useful. If there really is a bug
in pmemd, I WANT to get it fixed immediately. The last thing in the world I
want is nebulous reports of strange behaviour that may or may not be related
to the simulation instead of the software. Once the system starts
expanding, I am not at all surprised that things go south in a hurry. I am
not sure how several data structures would respond to a significant increase
in the unit cell size; in normal simulations, presuming we are not doing
bomb blasts, this doesn't happen. Anyway, it is interesting, and I want to
get to the bottom of it, so please send the files.
Regards - Bob
----- Original Message -----
From: "james tomomi macdonald" <j.macdonald.mail.cryst.bbk.ac.uk>
To: <amber.scripps.edu>
Sent: Friday, August 22, 2003 11:37 AM
Subject: AMBER: problems with pmemd
>
> Hi,
>
> I am experiencing another strange error with pmemd, which is probably
> connected to my previous problems!
>
> I have been running a constant pressure/temperature at 300K simulation for
> almost 5ns, when suddenly the temperature jumped to over 500K, then
> gradually fell back. I visually looked at the crd file with VMD, and you
> observe at this point that all the atoms move in a concerted motion in one
> direction, and you can also see layers of high and low water density
> appear.
>
> I then tried running exactly the same simulation with the same restart
> file and the same parameters on sander7, and this did not occur. I show
> the relevent parts of the output files below:
>
> pmemd:
>
> NSTEP = 6500 TIME(PS) = 4961.500 TEMP(K) = 298.47 PRESS = 63.3
> Etot = -41733.7676 EKtot = 10194.6513 EPtot = -51928.4189
> BOND = 292.5101 ANGLE = 728.0762 DIHED = 845.7586
> 1-4 NB = 310.2881 1-4 EEL = 3978.8609 VDWAALS = 6489.8158
> EELEC = -64573.7287 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4626.5850 VIRIAL = 4395.7938 VOLUME = 168813.4283
> Density = 1.0135
> Ewald error estimate: 0.7729E-06
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6600 TIME(PS) = 4961.600 TEMP(K) = 318.95 PRESS = 289.9
> Etot = -39330.7480 EKtot = 10894.0969 EPtot = -50224.8450
> BOND = 270.7332 ANGLE = 774.0337 DIHED = 856.7722
> 1-4 NB = 308.1194 1-4 EEL = 3962.1139 VDWAALS = 6547.6415
> EELEC = -62944.2589 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4810.6653 VIRIAL = 3754.2828 VOLUME = 168777.5285
> Density = 1.0137
> Ewald error estimate: 0.1708E-01
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6700 TIME(PS) = 4961.700 TEMP(K) = 357.95 PRESS = 286.2
> Etot = -36504.3138 EKtot = 12226.1990 EPtot = -48730.5128
> BOND = 321.2632 ANGLE = 747.7915 DIHED = 846.2733
> 1-4 NB = 315.5974 1-4 EEL = 3960.5898 VDWAALS = 6010.7395
> EELEC = -60932.7674 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 5114.1891 VIRIAL = 4058.7757 VOLUME = 170772.0682
> Density = 1.0018
> Ewald error estimate: 0.1601E-01
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6800 TIME(PS) = 4961.800 TEMP(K) = 390.12 PRESS = 418.9
> Etot = -34301.1423 EKtot = 13324.8770 EPtot = -47626.0194
> BOND = 298.6391 ANGLE = 820.5181 DIHED = 844.3443
> 1-4 NB = 308.4515 1-4 EEL = 3940.1651 VDWAALS = 5379.3324
> EELEC = -59217.4698 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 5403.9209 VIRIAL = 3836.1876 VOLUME = 173353.0579
> Density = 0.9869
> Ewald error estimate: 0.7236E-02
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6900 TIME(PS) = 4961.900 TEMP(K) = 421.96 PRESS = 785.4
> Etot = -31076.8311 EKtot = 14412.2642 EPtot = -45489.0952
> BOND = 294.2989 ANGLE = 779.3968 DIHED = 879.6072
> 1-4 NB = 317.9626 1-4 EEL = 3941.5282 VDWAALS = 5084.2504
> EELEC = -56786.1392 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 5864.7529 VIRIAL = 2877.9554 VOLUME = 176136.6267
> Density = 0.9713
> Ewald error estimate: 0.1240E-02
>
> --------------------------------------------------------------------------
----
>
> check COM velocity, temp: 0.008719 0.11(Removed)
>
> NSTEP = 7000 TIME(PS) = 4962.000 TEMP(K) = 452.71 PRESS = 1121.2
> Etot = -30028.8195 EKtot = 15462.6471 EPtot = -45491.4666
> BOND = 289.4439 ANGLE = 755.1666 DIHED = 866.9537
> 1-4 NB = 309.4601 1-4 EEL = 3951.9019 VDWAALS = 4989.5962
> EELEC = -56653.9891 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 6272.9548 VIRIAL = 1928.5536 VOLUME = 179455.1194
> Density = 0.9534
> Ewald error estimate: 0.2364E-01
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 7100 TIME(PS) = 4962.100 TEMP(K) = 474.42 PRESS = 1377.2
> Etot = -26714.0726 EKtot = 16204.0949 EPtot = -42918.1674
> BOND = 295.2772 ANGLE = 766.4333 DIHED = 892.7033
> 1-4 NB = 302.5419 1-4 EEL = 3953.6028 VDWAALS = 4702.3717
> EELEC = -53831.0978 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 6460.5940 VIRIAL = 1018.1852 VOLUME = 183029.9082
> Density = 0.9347
> Ewald error estimate: 0.3551E-02
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 7200 TIME(PS) = 4962.200 TEMP(K) = 505.94 PRESS = 1294.1
> Etot = -26808.0582 EKtot = 17280.7629 EPtot = -44088.8211
> BOND = 300.5836 ANGLE = 748.5357 DIHED = 874.6213
> 1-4 NB = 315.1921 1-4 EEL = 3922.2050 VDWAALS = 4535.0485
> EELEC = -54785.0072 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 6913.5681 VIRIAL = 1690.8046 VOLUME = 186915.4954
> Density = 0.9153
> Ewald error estimate: 0.8253E-01
>
> --------------------------------------------------------------------------
----
>
>
>
> sander 7:
>
>
> NSTEP = 6500 TIME(PS) = 4961.500 TEMP(K) = 301.21 PRESS = -62.9
> Etot = -41834.7763 EKtot = 10287.9979 EPtot = -52122.7742
> BOND = 274.5862 ANGLE = 728.2804 DIHED = 833.3658
> 1-4 NB = 319.1534 1-4 EEL = 3962.3669 VDWAALS = 6524.3781
> EELEC = -64764.9049 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4542.5932 VIRIAL = 4772.5128 VOLUME = 169291.9523
> Density = 1.0106
> Ewald error estimate: 0.3793E-05
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6600 TIME(PS) = 4961.600 TEMP(K) = 301.29 PRESS = -49.2
> Etot = -41833.2442 EKtot = 10290.6459 EPtot = -52123.8901
> BOND = 267.5927 ANGLE = 737.1375 DIHED = 846.7068
> 1-4 NB = 306.8492 1-4 EEL = 3970.7898 VDWAALS = 6561.6651
> EELEC = -64814.6312 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4571.9192 VIRIAL = 4751.6116 VOLUME = 169051.8821
> Density = 1.0120
> Ewald error estimate: 0.1122E-05
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6700 TIME(PS) = 4961.700 TEMP(K) = 298.50 PRESS = 46.9
> Etot = -41839.1107 EKtot = 10195.6841 EPtot = -52034.7948
> BOND = 277.8845 ANGLE = 726.3443 DIHED = 835.6000
> 1-4 NB = 304.5320 1-4 EEL = 3947.3038 VDWAALS = 6542.4171
> EELEC = -64668.8767 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4556.7967 VIRIAL = 4385.8516 VOLUME = 168938.1701
> Density = 1.0127
> Ewald error estimate: 0.4191E-05
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6800 TIME(PS) = 4961.800 TEMP(K) = 298.80 PRESS = 124.4
> Etot = -41829.7811 EKtot = 10205.7771 EPtot = -52035.5582
> BOND = 271.2634 ANGLE = 714.7948 DIHED = 861.1520
> 1-4 NB = 327.3404 1-4 EEL = 3973.7338 VDWAALS = 6593.3963
> EELEC = -64777.2389 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4580.3234 VIRIAL = 4126.4097 VOLUME = 168934.4775
> Density = 1.0127
> Ewald error estimate: 0.1744E-04
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 6900 TIME(PS) = 4961.900 TEMP(K) = 301.15 PRESS = -64.9
> Etot = -41820.1646 EKtot = 10286.1837 EPtot = -52106.3482
> BOND = 252.4161 ANGLE = 714.1134 DIHED = 859.9520
> 1-4 NB = 324.1893 1-4 EEL = 3959.5846 VDWAALS = 6402.4153
> EELEC = -64619.0189 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4602.2684 VIRIAL = 4838.9847 VOLUME = 168968.4328
> Density = 1.0125
> Ewald error estimate: 0.4794E-05
>
> --------------------------------------------------------------------------
----
>
> check COM velocity, temp: 0.000000 0.00(Removed)
>
> NSTEP = 7000 TIME(PS) = 4962.000 TEMP(K) = 301.20 PRESS = 7.1
> Etot = -41815.3976 EKtot = 10287.7635 EPtot = -52103.1611
> BOND = 261.1966 ANGLE = 749.5415 DIHED = 862.3520
> 1-4 NB = 314.4989 1-4 EEL = 3946.0642 VDWAALS = 6503.3912
> EELEC = -64740.2056 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4629.9481 VIRIAL = 4603.9726 VOLUME = 168945.3619
> Density = 1.0127
> Ewald error estimate: 0.8475E-05
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 7100 TIME(PS) = 4962.100 TEMP(K) = 299.29 PRESS = -44.3
> Etot = -41816.0813 EKtot = 10222.4834 EPtot = -52038.5648
> BOND = 265.0638 ANGLE = 714.7398 DIHED = 860.1382
> 1-4 NB = 316.6735 1-4 EEL = 3940.3158 VDWAALS = 6528.1526
> EELEC = -64663.6485 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4517.6002 VIRIAL = 4678.9184 VOLUME = 168672.9438
> Density = 1.0143
> Ewald error estimate: 0.6403E-05
>
> --------------------------------------------------------------------------
----
>
>
> NSTEP = 7200 TIME(PS) = 4962.200 TEMP(K) = 297.11 PRESS = 264.1
> Etot = -41819.3082 EKtot = 10147.8771 EPtot = -51967.1853
> BOND = 275.7279 ANGLE = 736.9878 DIHED = 855.7601
> 1-4 NB = 305.4095 1-4 EEL = 3938.0708 VDWAALS = 6571.1477
> EELEC = -64650.2892 EHBOND = 0.0000 RESTRAINT = 0.0000
> EKCMT = 4569.6899 VIRIAL = 3608.3405 VOLUME = 168587.5174
> Density = 1.0148
> Ewald error estimate: 0.8551E-05
>
> --------------------------------------------------------------------------
----
>
>
> Cheers,
>
> James.
>
>
>
> -----------------------------------------------------------------------
> The AMBER Mail Reflector
> To post, send mail to amber.scripps.edu
> To unsubscribe, send "unsubscribe amber" to majordomo.scripps.edu
>
>
-----------------------------------------------------------------------
The AMBER Mail Reflector
To post, send mail to amber.scripps.edu
To unsubscribe, send "unsubscribe amber" to majordomo.scripps.edu
Received on Fri Aug 22 2003 - 17:53:00 PDT