Re: Problem with running replica-exchange umbrella sampling of polarizable system

From: zeynab hosseini (hosseinizeynab93_at_gmail.com)
Date: Thu Sep 02 2021 - 04:40:05 CDT

Dear Hemanth,

Thank you for your answer. The problem is fixed now..

All the best,
Zeynab

On Thu, Sep 2, 2021 at 5:40 AM Hemanth Haridas <hemanth.h_at_iitgn.ac.in>
wrote:

> Dear Zeynab,
>
> Can you please post the psf and the input file that you used. I have some
> experience in setting up and running umbrella sampling simulations using
> Drude FF.
>
> On Thu, Sep 2, 2021 at 12:51 PM zeynab hosseini <
> hosseinizeynab93_at_gmail.com> wrote:
>
>> Hi Giacomo,
>>
>> Thank you so much for your reply. Sorry about that but unfortunately I
>> couldn't completely understand your prescription. I made 10
>> windows centered at 6.7A, 6.8A, 6.9A, 7A, 8A, 9A, 11A, 13A, 15A and 17A.
>> The output I already sent is related to window-0 centered at 6.7A. I
>> understood to perform standard MD for each replica independently(short
>> one)? but what do you mean by setting the centers of harmonic restraints to
>> zero? You mean for example for the window-0 I put the center 0 instead of
>> 6.7? That would't produce problem?
>>
>> All the best,
>> Zeynab
>>
>> On Wed, Sep 1, 2021 at 10:01 AM Giacomo Fiorin <giacomo.fiorin_at_gmail.com>
>> wrote:
>>
>>> Hi Zeynab, I've not used yet polarizable models in NAMD, so I don't know
>>> specifically where the error arises. Assuming that this is a symptom of an
>>> unstable configuration, what I would try to do is doing for each replica a
>>> short MD run of 100-1000 steps on your workstation or an interactive node.
>>> Start with the centers of the harmonic restraints to zero as you have shown
>>> (i.e. test the configuration of the first replica), and then do the same
>>> for all other values that will be set by the REUS script, which will modify
>>> that center for all other replicas.
>>>
>>> Giacomo
>>>
>>> On Wed, Sep 1, 2021 at 6:28 AM zeynab hosseini <
>>> hosseinizeynab93_at_gmail.com> wrote:
>>>
>>>> Dear All,
>>>>
>>>> I want to perform a replica-exchange umbrella sampling (reUS) on a
>>>> system composed of a nanotube and an amino acid solvated in water using a
>>>> polarizable force field (Drude). I did the standard MD of the system with
>>>> no problem using NAMD 2.14. The collective variable for my system is the
>>>> radial distance of the mass center of amino acid from the mass center of
>>>> the carbon nanotube. Collective variable is divided by 10 windows. As soon
>>>> as, I perform the reUS simulation I get the following error:
>>>>
>>>> colvars: Collective variables biases initialized, 2 in total.
>>>> colvars:
>>>> ----------------------------------------------------------------------
>>>> colvars: Collective variables module (re)initialized.
>>>> colvars:
>>>> ----------------------------------------------------------------------
>>>> colvars: Updating NAMD interface:
>>>> colvars: updating atomic data (0 atoms).
>>>> colvars: updating group data (2 scalable groups, 344 atoms in total).
>>>> colvars: updating grid object data (0 grid objects in total).
>>>> colvars: Re-initialized atom group for variable "Translocation":0/0. 24
>>>> atoms: total mass = 154.105, total charge = -0.279001.
>>>> colvars: Re-initialized atom group for variable "Translocation":0/1.
>>>> 320 atoms: total mass = 1921.76, total charge = 5.91999.
>>>> colvars: The final output state file will be
>>>> "output/0/win-out.job0.0.colvars.state".
>>>> colvars: Opening trajectory file "output/0/win-out.job0.0.colvars.traj".
>>>> colvars: Redefining the Tcl "cv" command to the new script interface.
>>>> Info: Startup phase 13 took 0.00555027 s, 66.3516 MB of memory in use
>>>> Info: Startup phase 14 took 5.4094e-05 s, 66.3516 MB of memory in use
>>>> Info: Startup phase 15 took 4.1293e-05 s, 67.6719 MB of memory in use
>>>> Info: Finished startup at 26.3569 s, 67.6719 MB of memory in use
>>>>
>>>> colvars: # centers = { 6.7 }
>>>> colvars: # forceConstant = 0.025 [default]
>>>> TCL: Running for 1000 steps
>>>> colvars: Updating NAMD interface:
>>>> colvars: updating atomic data (0 atoms).
>>>> colvars: updating group data (2 scalable groups, 344 atoms in total).
>>>> colvars: updating grid object data (0 grid objects in total).
>>>> colvars: Re-initialized atom group for variable "Translocation":0/0. 24
>>>> atoms: total mass = 154.105, total charge = -0.279001.
>>>> colvars: Re-initialized atom group for variable "Translocation":0/1.
>>>> 320 atoms: total mass = 1921.76, total charge = 5.91999.
>>>> colvars: The final output state file will be
>>>> "output/0/win-out.job0.0.colvars.state".
>>>> FATAL ERROR: Bad global Thole count! (0 vs 707)
>>>>
>>>> FATAL ERROR: See http://www.ks.uiuc.edu/Research/namd/bugreport.html
>>>> [Partition 0][Node 0] End of program
>>>>
>>>> I have to say that the collective variable is considered to be the mass
>>>> center of a group of atoms with no lone-pair. Since the lone-pairs are
>>>> massless.
>>>> Here is the collective variable conformation file (US-base.in):
>>>> colvarsTrajFrequency 100
>>>>
>>>> colvar {
>>>> name Translocation
>>>> width 0.1
>>>> lowerboundary 4.5
>>>> upperboundary 18.8
>>>> lowerwall 6.5
>>>> upperwall 16.8
>>>> lowerwallconstant 100.0
>>>> upperwallconstant 100.0
>>>>
>>>> distanceXY {
>>>> main {
>>>> atomnumbers {1 2 6 7 9 10 11 12 13 14 19 20 23 24 25 26 28 29
>>>> 31 32 34 35 37 38 }
>>>> }
>>>> ref {
>>>> atomnumbers {
>>>>
>>>> 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
>>>> 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89
>>>> 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110
>>>> 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129
>>>> 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148
>>>> 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167
>>>> 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186
>>>> 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205
>>>> 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224
>>>> 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243
>>>> 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262
>>>> 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281
>>>> 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300
>>>> 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319
>>>> 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338
>>>> 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357
>>>> 358 359 360}
>>>> }
>>>> axis ( 0.0, 0.0, 1.0 )
>>>> }
>>>> }
>>>>
>>>> harmonic {
>>>> name Z
>>>> colvars Translocation
>>>> centers 0.0
>>>> forceConstant 0.025;# 2.5 * 0.1^2 = 0.025
>>>> }
>>>>
>>>>
>>>>
>>>> Here is the NAMD configuration file to run the simulation:
>>>> structure input/rm-bonds-modified.psf
>>>> ###coordinates input/start%d.pdb
>>>>
>>>> paraTypeCharmm on
>>>> parameters toppar_drude/toppar_drude_master_protein_2019g.str;
>>>> parameters toppar_drude/toppar_drude_lipid_2017c.str;
>>>> parameters toppar_drude/toppar_drude_model_2019g.str;
>>>> parameters toppar_drude/toppar_drude_carbohydrate_2019a.str;
>>>> parameters toppar_drude/toppar_drude_nucleic_acid_2017c.str;
>>>>
>>>>
>>>> # Force-Field Parameters
>>>> exclude scaled1-4
>>>> 1-4scaling 1.0
>>>> cutoff 12.
>>>> switching on
>>>> ##vdwForceSwitching on
>>>> switchdist 10.
>>>> pairlistdist 13.5
>>>>
>>>>
>>>> # Integrator Parameters
>>>> timestep 1.0 ;# 1fs/step (only if needed to finish quickly)
>>>> #rigidBonds water
>>>> nonbondedFreq 2
>>>> fullElectFrequency 4
>>>> stepspercycle 20
>>>>
>>>>
>>>> # Constant Temperature Control
>>>> langevin on ;# do langevin dynamicsgmail.google.com
>>>> <https://urldefense.com/v3/__http://dynamicsgmail.google.com__;!!DZ3fjg!rr1eS3jzXnhCzE3epjT3nvhSxHDTpqYVUUEui1CrLsbun9UvEQqaExjXfxLYr-Ns8Q$>
>>>> langevinDamping 1 ;# damping coefficient (gamma) of 5/ps
>>>> langevinTemp $temperature
>>>> langevinHydrogen off ;# don't couple langevin bath to hydrogens
>>>>
>>>> # Periodic Boundary Conditions
>>>> #cellBasisVector1 61.5 0. 0.
>>>> #cellBasisVector2 0. 61.5 0.
>>>> #cellBasisVector3 0. 0 71.5
>>>> #cellOrigin -16.06 -14.75 -12
>>>>
>>>> #wrapAll on
>>>>
>>>> # PME (for full-system periodic electrostatics)
>>>> PME yes
>>>> PMEGridSpacing 1.0
>>>>
>>>> # Constant Pressure Control (variable volume)
>>>> useGroupPressure yes
>>>> useConstantArea yes
>>>> useFlexibleCell yes
>>>> margin 5
>>>>
>>>>
>>>> Would be very much grateful if somebody could guide me..
>>>>
>>>> All the best,
>>>> Zeynab
>>>>
>>>
>
> --
> *Hemanth H 18310019*
> Research Scholar
> IIT Gandhinagar
>

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