[gmx-users] LINCS error

Justin A. Lemkul jalemkul at vt.edu
Fri Oct 9 17:16:05 CEST 2009



Yongchul Chung wrote:
> Hi again gmx-users,
> 
> I ran into LINCS error again when I tried to incorporate pressure 
> scaling parameters.
> It seems like the initial pressure and temperature is erroneously large 
> as shown in the md.log file below. can anyone tell me how to fix this?
> 

Did you run energy minimization first?

-Justin

> Thanks
> 
> Input Parameters:
>    integrator           = md
>    nsteps               = 100000
>    init_step            = 0
>    ns_type              = Grid
>    nstlist              = 10
>    ndelta               = 2
>    nstcomm              = 1
>    comm_mode            = Linear
>    nstlog               = 10
>    nstxout              = 500
>    nstvout              = 1000
>    nstfout              = 0
>    nstenergy            = 10
>    nstxtcout            = 0
>    init_t               = 0
>    delta_t              = 0.002
>    xtcprec              = 1000
>    nkx                  = 0
>    nky                  = 0
>    nkz                  = 0
>    pme_order            = 4
>    ewald_rtol           = 1e-05
>    ewald_geometry       = 0
>    epsilon_surface      = 0
>    optimize_fft         = TRUE
>    ePBC                 = xyz
>    bPeriodicMols        = FALSE
>    bContinuation        = FALSE
>    bShakeSOR            = FALSE
>    etc                  = V-rescale
>    epc                  = Berendsen
>    epctype              = Isotropic
>    tau_p                = 1
>    ref_p (3x3):
>       ref_p[    0]={ 1.01325e+00,  0.00000e+00,  0.00000e+00}
>       ref_p[    1]={ 0.00000e+00,  1.01325e+00,  0.00000e+00}
>       ref_p[    2]={ 0.00000e+00,  0.00000e+00,  1.01325e+00}
>    compress (3x3):
>       compress[    0]={ 4.50000e-03,  0.00000e+00,  0.00000e+00}
>       compress[    1]={ 0.00000e+00,  4.50000e-03,  0.00000e+00}
>       compress[    2]={ 0.00000e+00,  0.00000e+00,  4.50000e-03}
>    refcoord_scaling     = No
>    posres_com (3):
>       posres_com[0]= 0.00000e+00
>       posres_com[1]= 0.00000e+00
>       posres_com[2]= 0.00000e+00
>    posres_comB (3):
>       posres_comB[0]= 0.00000e+00
>       posres_comB[1]= 0.00000e+00
>       posres_comB[2]= 0.00000e+00
>    andersen_seed        = 815131
>    rlist                = 1
>    rtpi                 = 0.05
>    coulombtype          = Cut-off
>    rcoulomb_switch      = 0
>    rcoulomb             = 1.4
>    vdwtype              = Cut-off
>    rvdw_switch          = 0
>    rvdw                 = 1.4
>    epsilon_r            = 1
>    epsilon_rf           = 1
>    tabext               = 1
>    implicit_solvent     = No
>    gb_algorithm         = Still
>    gb_epsilon_solvent   = 80
>    nstgbradii           = 1
>    rgbradii             = 2
>    gb_saltconc          = 0
>    gb_obc_alpha         = 1
>    gb_obc_beta          = 0.8
>    gb_obc_gamma         = 4.85
>    sa_surface_tension   = 2.092
>    DispCorr             = No
>    free_energy          = no
>    init_lambda          = 0
>    sc_alpha             = 0
>    sc_power             = 0
>    sc_sigma             = 0.3
>    delta_lambda         = 0
>    nwall                = 0
>    wall_type            = 9-3
>    wall_atomtype[0]     = -1
>    wall_atomtype[1]     = -1
>    wall_density[0]      = 0
>    wall_density[1]      = 0
>    wall_ewald_zfac      = 3
>    pull                 = no
>    disre                = No
>    disre_weighting      = Conservative
>    disre_mixed          = FALSE
>    dr_fc                = 1000
>    dr_tau               = 0
>    nstdisreout          = 100
>    orires_fc            = 0
>    orires_tau           = 0
>    nstorireout          = 100
>    dihre-fc             = 1000
>    em_stepsize          = 0.01
>    em_tol               = 10
>    niter                = 20
>    fc_stepsize          = 0
>    nstcgsteep           = 1000
>    nbfgscorr            = 10
>    ConstAlg             = Lincs
>    shake_tol            = 0.0001
>    lincs_order          = 4
>    lincs_warnangle      = 30
>    lincs_iter           = 1
>    bd_fric              = 0
>    ld_seed              = 1993
>    cos_accel            = 0
>    deform (3x3):
>       deform[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>       deform[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>       deform[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>    userint1             = 0
>    userint2             = 0
>    userint3             = 0
>    userint4             = 0
>    userreal1            = 0
>    userreal2            = 0
>    userreal3            = 0
>    userreal4            = 0
> grpopts:
>    nrdf:       11297
>    ref_t:         300
>    tau_t:         0.1
> anneal:          No
> ann_npoints:           0
>    acc:               0           0           0
>    nfreeze:           N           N           N
>    energygrp_flags[  0]: 0
>    efield-x:
>       n = 0
>    efield-xt:
>       n = 0
>    efield-y:
>       n = 0
>    efield-yt:
>       n = 0
>    efield-z:
>       n = 0
>    efield-zt:
>       n = 0
>    bQMMM                = FALSE
>    QMconstraints        = 0
>    QMMMscheme           = 0
>    scalefactor          = 1
> qm_opts:
>    ngQM                 = 0
> Table routines are used for coulomb: FALSE
> Table routines are used for vdw:     FALSE
> Cut-off's:   NS: 1   Coulomb: 1.4   LJ: 1.4
> System total charge: -0.000
> Configuring nonbonded kernels...
> Testing AMD 3DNow support... not present.
> Testing ia32 SSE support... present.
> 
> 
> Removing pbc first time
> 
> Initializing LINear Constraint Solver
> 
> The number of constraints is 5500
> Center of mass motion removal mode is Linear
> We have the following groups for center of mass motion removal:
>   0:  rest
> 
> There are: 5600 Atoms
> Max number of connections per atom is 4
> Total number of connections is 11000
> Max number of graph edges per atom is 4
> Total number of graph edges is 11000
> 
> Constraining the starting coordinates (step 0)
> 
> Constraining the coordinates at t0-dt (step 0)
> RMS relative constraint deviation after constraining: 4.85e-05
> Initial temperature: 307.706 K
> 
> Started mdrun on node 0 Fri Oct  9 11:09:36 2009
> 
>            Step           Time         Lambda
>               0        0.00000        0.00000
> 
> Grid: 7 x 7 x 7 cells
>    Energies (kJ/mol)
>         LJ (SR)        LJ (LR)   Coulomb (SR)   Coulomb (LR)      Potential
>     4.09130e+05   -2.61414e+01   -1.20894e+04   -4.35981e+02    3.96578e+05
>     Kinetic En.   Total Energy    Temperature Pressure (bar)  Cons. rmsd ()
>     4.24944e+04    4.39073e+05    9.04819e+02   -1.31995e+04    4.03210e-04
> 
> 
> Step 1  Warning: pressure scaling more than 1%, mu: 0.960399 0.960399 
> 0.960399
> 
> Step 3  Warning: pressure scaling more than 1%, mu: 1.13142 1.13142 1.13142
> 
> Step 4  Warning: pressure scaling more than 1%, mu: 1.81135 1.81135 1.81135
> 
> Step 5  Warning: pressure scaling more than 1%, mu: 3.4866e+09 
> 3.4866e+09 3.4866e+09
> 
> -------------------------------------------------------
> Program mdrun, VERSION 4.0.2
> Source code file: constr.c, line: 136
> 
> Fatal error:
> Too many LINCS warnings (5235)
> If you know what you are doing you can adjust the lincs warning 
> threshold in your mdp file
> or set the environment variable GMX_MAXCONSTRWARN to -1,
> but normally it is better to fix the problem
> 
> 
> On Thu, Oct 8, 2009 at 3:05 PM, Justin A. Lemkul <jalemkul at vt.edu 
> <mailto:jalemkul at vt.edu>> wrote:
> 
> 
> 
>     Yongchul Chung wrote:
> 
>         Hi guys,
> 
>         As Justin pointed out, it was the problem with md simulation
>         blowing up. I also had coloumbtype=PME and had to switch to
>         cut-off to make my simulation run faster.
> 
> 
>     And it will be substantially less accurate than using PME.  I would
>     say Jochen's advice is the best - reduce the time step to something
>     reasonable, and use PME.
> 
>     -Justin
> 
>         Thanks for all the help.
> 
>         On Thu, Oct 8, 2009 at 11:44 AM, Jochen Hub
>         <jochen at xray.bmc.uu.se <mailto:jochen at xray.bmc.uu.se>
>         <mailto:jochen at xray.bmc.uu.se <mailto:jochen at xray.bmc.uu.se>>>
>         wrote:
> 
> 
> 
> 
>             delta_t              = 0.01
> 
>            You are using a 10 fs timestep!!! That is way too long.
>         Standard is
>            2 (with bond constraints).
> 
> 
> 
>            Yongchul Chung wrote:
> 
>                Hi all,
> 
>                I am trying to simulate 100 molecules of n-alkane
>         molecules but
>                keep receiving LINC errors.
>                When I completed steepest descent I received following msg:
> 
>                Steepest Descents converged to Fmax < 500 in 819 steps
>                Potential Energy  =  1.7174361e+05
>                Maximum force     =  4.4903098e+02 on atom 172
>                Norm of force     =  3.0003010e+01
> 
>                Then I performed mdrun with the output of this file and gets
>                LINCS warning:
> 
> 
>                Input Parameters:
>                  integrator           = md
>                  nsteps               = 8000
>                  init_step            = 0
>                  ns_type              = Grid
>                  nstlist              = 10
>                  ndelta               = 2
>                  nstcomm              = 1
>                  comm_mode            = Linear
>                  nstlog               = 10
>                  nstxout              = 250
>                  nstvout              = 1000
>                  nstfout              = 0
>                  nstenergy            = 10
>                  nstxtcout            = 0
>                  init_t               = 0
>                  delta_t              = 0.01
>                  xtcprec              = 1000
>                  nkx                  = 125
>                  nky                  = 125
>                  nkz                  = 125
>                  pme_order            = 4
>                  ewald_rtol           = 1e-05
>                  ewald_geometry       = 0
>                  epsilon_surface      = 0
>                  optimize_fft         = TRUE
>                  ePBC                 = xyz
>                  bPeriodicMols        = FALSE
>                  bContinuation        = FALSE
>                  bShakeSOR            = FALSE
>                  etc                  = V-rescale
>                  epc                  = No
>                  epctype              = Isotropic
>                  tau_p                = 1
>                  ref_p (3x3):
>                     ref_p[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>                     ref_p[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>                     ref_p[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>                  compress (3x3):
>                     compress[    0]={ 0.00000e+00,  0.00000e+00,
>          0.00000e+00}
>                     compress[    1]={ 0.00000e+00,  0.00000e+00,
>          0.00000e+00}
>                     compress[    2]={ 0.00000e+00,  0.00000e+00,
>          0.00000e+00}
>                  refcoord_scaling     = No
>                  posres_com (3):
>                     posres_com[0]= 0.00000e+00
>                     posres_com[1]= 0.00000e+00
>                     posres_com[2]= 0.00000e+00
>                  posres_comB (3):
>                     posres_comB[0]= 0.00000e+00
>                     posres_comB[1]= 0.00000e+00
>                     posres_comB[2]= 0.00000e+00
>                  andersen_seed        = 815131
>                  rlist                = 1
>                  rtpi                 = 0.05
>                  coulombtype          = PME
>                  rcoulomb_switch      = 0
>                  rcoulomb             = 1
>                  vdwtype              = Cut-off
>                  rvdw_switch          = 0
>                  rvdw                 = 2
>                  epsilon_r            = 1
>                  epsilon_rf           = 1
>                  tabext               = 1
>                  implicit_solvent     = No
>                  gb_algorithm         = Still
>                  gb_epsilon_solvent   = 80
>                  nstgbradii           = 1
>                  rgbradii             = 2
>                  gb_saltconc          = 0
>                  gb_obc_alpha         = 1
>                  gb_obc_beta          = 0.8
>                  gb_obc_gamma         = 4.85
>                  sa_surface_tension   = 2.092
>                  DispCorr             = No
>                  free_energy          = no
>                  init_lambda          = 0
>                  sc_alpha             = 0
>                  sc_power             = 0
>                  sc_sigma             = 0.3
>                  delta_lambda         = 0
>                  nwall                = 0
>                  wall_type            = 9-3
>                  wall_atomtype[0]     = -1
>                  wall_atomtype[1]     = -1
>                  wall_density[0]      = 0
>                  wall_density[1]      = 0
>                  wall_ewald_zfac      = 3
>                  pull                 = no
>                  disre                = No
>                  disre_weighting      = Conservative
>                  disre_mixed          = FALSE
>                  dr_fc                = 1000
>                  dr_tau               = 0
>                  nstdisreout          = 100
>                  orires_fc            = 0
>                  orires_tau           = 0
>                  nstorireout          = 100
>                  dihre-fc             = 1000
>                  em_stepsize          = 0.01
>                  em_tol               = 10
>                  niter                = 20
>                  fc_stepsize          = 0
>                  nstcgsteep           = 1000
>                  nbfgscorr            = 10
>                  ConstAlg             = Lincs
>                  shake_tol            = 0.0001
>                  lincs_order          = 4
>                  lincs_warnangle      = 30
>                  lincs_iter           = 1
>                  bd_fric              = 0
>                  ld_seed              = 1993
>                  cos_accel            = 0
>                  deform (3x3):
>                     deform[    0]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>                     deform[    1]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>                     deform[    2]={ 0.00000e+00,  0.00000e+00,  0.00000e+00}
>                  userint1             = 0
>                  userint2             = 0
>                  userint3             = 0
>                  userint4             = 0
>                  userreal1            = 0
>                  userreal2            = 0
>                  userreal3            = 0
>                  userreal4            = 0
>                grpopts:
>                  nrdf:       11297
>                  ref_t:         300
>                  tau_t:         0.1
>                anneal:          No
>                ann_npoints:           0
>                  acc:               0           0           0
>                  nfreeze:           N           N           N
>                  energygrp_flags[  0]: 0
>                  efield-x:
>                     n = 0
>                  efield-xt:
>                     n = 0
>                  efield-y:
>                     n = 0
>                  efield-yt:
>                     n = 0
>                  efield-z:
>                     n = 0
>                  efield-zt:
>                     n = 0
>                  bQMMM                = FALSE
>                  QMconstraints        = 0
>                  QMMMscheme           = 0
>                  scalefactor          = 1
>                qm_opts:
>                  ngQM                 = 0
>                Table routines are used for coulomb: TRUE
>                Table routines are used for vdw:     FALSE
>                Will do PME sum in reciprocal space.
> 
>                ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
>                U. Essman, L. Perela, M. L. Berkowitz, T. Darden, H. Lee
>         and L.
>                G. Pedersen
>                A smooth particle mesh Ewald method
>                J. Chem. Phys. 103 (1995) pp. 8577-8592
>                -------- -------- --- Thank You --- -------- --------
> 
>                Using a Gaussian width (1/beta) of 0.320163 nm for Ewald
>                Cut-off's:   NS: 1   Coulomb: 1   LJ: 2
>                System total charge: -0.000
>                Generated table with 1500 data points for Ewald.
>                Tabscale = 500 points/nm
>                Generated table with 1500 data points for LJ6.
>                Tabscale = 500 points/nm
>                Generated table with 1500 data points for LJ12.
>                Tabscale = 500 points/nm
>                Configuring nonbonded kernels...
>                Testing AMD 3DNow support... not present.
>                Testing ia32 SSE support... present.
> 
> 
>                Removing pbc first time
> 
>                Initializing LINear Constraint Solver
> 
>                ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
>                B. Hess and H. Bekker and H. J. C. Berendsen and J. G. E.
>         M. Fraaije
>                LINCS: A Linear Constraint Solver for molecular simulations
>                J. Comp. Chem. 18 (1997) pp. 1463-1472
>                -------- -------- --- Thank You --- -------- --------
> 
>                The number of constraints is 5500
>                Center of mass motion removal mode is Linear
>                We have the following groups for center of mass motion
>         removal:
>                 0:  rest
> 
>                ++++ PLEASE READ AND CITE THE FOLLOWING REFERENCE ++++
>                G. Bussi, D. Donadio and M. Parrinello
>                Canonical sampling through velocity rescaling
>                J. Chem. Phys. 126 (2007) pp. 014101
>                -------- -------- --- Thank You --- -------- --------
> 
>                There are: 5600 Atoms
>                Max number of connections per atom is 4
>                Total number of connections is 11000
>                Max number of graph edges per atom is 4
>                Total number of graph edges is 11000
> 
>                Constraining the starting coordinates (step 0)
> 
>                Constraining the coordinates at t0-dt (step 0)
>                RMS relative constraint deviation after constraining:
>         6.33e-04
>                Initial temperature: 306.393 K
> 
>                Started mdrun on node 0 Thu Oct  8 09:58:49 2009
> 
>                          Step           Time         Lambda
>                             0        0.00000        0.00000
> 
>                Grid: 25 x 25 x 25 cells
> 
>                -------------------------------------------------------
>                Program mdrun, VERSION 4.0.2
>                Source code file: constr.c, line: 136
> 
>                Fatal error:
>                Too many LINCS warnings (3821)
>                If you know what you are doing you can adjust the lincs
>         warning
>                threshold in your mdp file
>                or set the environment variable GMX_MAXCONSTRWARN to -1,
>                but normally it is better to fix the problem
>                -------------------------------------------------------
> 
>                Can anyone help me to navigate this issue?
>                Thanks
>                --        Yongchul "Greg" Chung
>                Graduate Student
>                Dept. of Chemical Engineering, Case Western Reserve
>         University
>              
>          ------------------------------------------------------------------------
> 
>                _______________________________________________
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> 
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> 
> 
> 
>            --    ---------------------------------------------------
>            Dr. Jochen Hub
>            Molecular Biophysics group
>            Dept. of Cell & Molecular Biology
>            Uppsala University. Box 596, 75124 Uppsala, Sweden.
>            Phone: +46-18-4714451 Fax: +46-18-511755
> 
>            ---------------------------------------------------
> 
>            _______________________________________________
>            gmx-users mailing list    gmx-users at gromacs.org
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>         <mailto:gmx-users-request at gromacs.org>
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>         <mailto:gmx-users-request at gromacs.org>>.
> 
>            Can't post? Read http://www.gromacs.org/mailing_lists/users.php
> 
> 
> 
> 
>         -- 
>         Yongchul "Greg" Chung
>         Graduate Student
>         Dept. of Chemical Engineering, Case Western Reserve University
> 
> 
>         ------------------------------------------------------------------------
> 
>         _______________________________________________
>         gmx-users mailing list    gmx-users at gromacs.org
>         <mailto:gmx-users at gromacs.org>
>         http://lists.gromacs.org/mailman/listinfo/gmx-users
>         Please search the archive at http://www.gromacs.org/search
>         before posting!
>         Please don't post (un)subscribe requests to the list. Use the
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> 
> 
>     -- 
>     ========================================
> 
>     Justin A. Lemkul
>     Ph.D. Candidate
>     ICTAS Doctoral Scholar
>     Department of Biochemistry
>     Virginia Tech
>     Blacksburg, VA
>     jalemkul[at]vt.edu <http://vt.edu> | (540) 231-9080
>     http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
>     ========================================
>     _______________________________________________
>     gmx-users mailing list    gmx-users at gromacs.org
>     <mailto:gmx-users at gromacs.org>
>     http://lists.gromacs.org/mailman/listinfo/gmx-users
>     Please search the archive at http://www.gromacs.org/search before
>     posting!
>     Please don't post (un)subscribe requests to the list. Use the www
>     interface or send it to gmx-users-request at gromacs.org
>     <mailto:gmx-users-request at gromacs.org>.
>     Can't post? Read http://www.gromacs.org/mailing_lists/users.php
> 
> 
> 
> 
> -- 
> Yongchul "Greg" Chung
> Graduate Student
> Dept. of Chemical Engineering, Case Western Reserve University

-- 
========================================

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

========================================



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