<div dir="ltr">Thanks for the explanation, it is really helpful, I will convert.<br><br>在 2018年5月3日星期四 UTC+8下午8:43:17，Matt W写道：<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div dir="ltr">Your input file has<div><br></div><div>STRESS_TENSOR NUMERICAL</div><div><br></div><div>this is probably very expensive. You don't need the full stress tensor for NPT_I, and analytical should be faster and more accurate than numerical (if available for your forcefield)</div><div><div><br><br>On Thursday, May 3, 2018 at 1:18:49 PM UTC+1, jie wu wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hello, Matt, thanks for the answer, but I am a little confused. Should I use the STRESS_TENSOR DIAGONAL_ANALYTICAL instead of the MM force field or to analysis the stress changing during the simulation?<br><br>在 2018年5月3日星期四 UTC+8下午6:04:44，Matt W写道：<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Probably unrelated to you actual question, but changing to<div><br></div><div><div>STRESS_TENSOR DIAGONAL_ANALYTICAL</div><div><br></div><div>should give you a big speed up.</div><div><br></div><div>Matt</div><div><br>On Thursday, May 3, 2018 at 1:37:55 AM UTC+1, <a>498...@qq.com</a> wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Hello, everyone, I want to simulate the melting structure of molten salts. The simulation began with crystal structure and temperature was set at 3000 K in NPT ensemble， which is far more higher than the melting point. However, the result is frustrating. After 100 ps runs, the ions still in crystal structure. The parameters in the force field is in published paper and widely used, so I wonder somewhere in the input file is wrong. The file is listed below, could anyone tell me the possible problems? Thanks very much.</div><div><br></div><div><br></div><div>&GLOBAL ! Section with general information regarding which kind of simulation to perform an parameters for the whole PROGRAM</div><div> PROJECT C6 ! Name of the project. This word will appear as part of a name of all ouput files (except main ouput file, specified with -o option)</div><div> RUN_TYPE MD ! Molecular Dynamics</div><div> PRINT_LEVEL low</div><div>&END GLOBAL</div><div><br></div><div><br></div><div>&FORCE_EVAL<span style="white-space:pre"> </span>! This section defines method for calculating energy and forces</div><div> METHOD FIST<span style="white-space:pre"> </span>! Using Molecular Mechanics</div><div> STRESS_TENSOR NUMERICAL</div><div> &MM</div><div> &FORCEFIELD<span style="white-space:pre"> </span>! This section specifies forcefield parameters</div><div> ..........</div><div> &END FORCEFIELD</div><div> &POISSON<span style="white-space:pre"> </span>! This section specifies parameters for the Poisson solver</div><div> &EWALD<span style="white-space:pre"> </span>! This section specifies parameters for the EWALD summation method (for the electrostatics)</div><div> EWALD_TYPE none<span style="white-space:pre"> </span>! Standard real-space coulomb potential is computed together with the non-bonded contributions.</div><div> &END EWALD</div><div> &END POISSON</div><div><span style="white-space:pre"> </span>&NEIGHBOR_LISTS</div><div><span style="white-space:pre"> </span> GEO_CHECK TRUE</div><div><span style="white-space:pre"> </span> NEIGHBOR_LISTS_FROM_SCRATCH TRUE</div><div><span style="white-space:pre"> </span> VERLET_SKIN 1</div><div> &END NEIGHBOR_LISTS </div><div> &END MM</div><div> &SUBSYS<span style="white-space:pre"> </span>! This section defines the system</div><div> &CELL<span style="white-space:pre"> </span>! Unit cell set up</div><div> ABC 22.56 22.56 22.56<span style="white-space:pre"> </span>! Lengths of the cell vectors A, B, and C</div><div> ALPHA_BETA_GAMMA 90.0 90.0 90.0</div><div> PERIODIC XYZ</div><div> &END CELL</div><div> &TOPOLOGY<span style="white-space:pre"> </span></div><div> COORD_FILE_NAME NaCl.xyz </div><div> COORDINATE xyz<span style="white-space:pre"> </span>! The type of the file is XYZ</div><div> &END TOPOLOGY</div><div> &END SUBSYS</div><div>&END FORCE_EVAL</div><div><br></div><div>&MOTION<span style="white-space:pre"> </span>! This section defines a set of tool connected with the motion of the nuclei.</div><div> &PRINT</div><div> &TRAJECTORY</div><div> LOG_PRINT_KEY T</div><div> FORMAT XMOL</div><div> &EACH</div><div> MD 10000</div><div> &END EACH</div><div> ADD_LAST NUMERIC </div><div> &END TRAJECTORY</div><div> &END PRINT</div><div> &MD </div><div> ENSEMBLE NPT_I</div><div> TEMPERATURE 3000</div><div><span style="white-space:pre"> </span>&BAROSTAT</div><div><span style="white-space:pre"> </span> PRESSURE 0</div><div><span style="white-space:pre"> </span> TEMPERATURE 3000</div><div><span style="white-space:pre"> </span>&END BAROSTAT</div><div><span style="white-space:pre"> </span>&THERMOSTAT</div><div> TYPE NOSE</div><div> REGION GLOBAL</div><div> &NOSE</div><div> TIMECON 100</div><div> LENGTH 3</div><div> MTS 2</div><div> &END NOSE</div><div> &END THERMOSTAT</div><div><span style="white-space:pre"> </span>TIMESTEP 1.0</div><div><span style="white-space:pre"> </span>STEPS 100000</div><div> &END MD</div><div><br></div><div> &PRINT</div><div> &RESTART</div><div> LOG_PRINT_KEY T</div><div> &EACH</div><div> MD 10000</div><div> &END EACH</div><div> ADD_LAST NUMERIC</div><div> &END RESTART</div><div> &END PRINT</div><div>&END MOTION</div><div> &END</div><div>&END MOTION</div><div><br></div></div></blockquote></div></div></div></blockquote></div></blockquote></div></div></div></blockquote></div>