Differences

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--- exercises:2016_uzh_cmest:faq [2016/12/05 11:05] – [How do I obtain a charge density difference?] scaravati
+++ exercises:2016_uzh_cmest:faq [2016/12/07 13:15] – [How do I build a slab model for a surface?] scaravati
@@ Line 14: / Line 14: @@
 <code>
-mpirun -n 8 cp2k.popt -i yourinput.inp -o youroutput.out
+$ mpirun -n 8 cp2k.popt -i yourinput.inp -o youroutput.out
 </code>
@@ Line 39: / Line 39: @@
 The basic usage to obtain a charge density difference is:
 <code>
-$PATH/cubecruncher.x -i input.cube -o output.cube -subtract subsystem.cube
+$ /users/scaravat/bin/cubecruncher.x -i input.cube -o output.cube -subtract subsystem.cube
 </code>
-===== How do I build a slab to model a surface? =====
+===== How do I build a slab model for a surface? =====
 E.g. by using [[http://jp-minerals.org/vesta/en/|VESTA]].
-A tutorial you can follow is available [[http://hjklol.mit.edu/content/building-slab-geometries-catalysis-vesta|here]].
+A tutorial is available [[http://hjklol.mit.edu/content/building-slab-geometries-catalysis-vesta|here]].
 Vesta comes preinstalled on ''tcopt3'', provided that you load the proper module.
 <code>
-module load vesta
+$ module load vesta
 </code>
+===== How do I obtain the stress tensor? =====
+You have to add the following snippet to the input file:
+<code>
+&FORCE_EVAL
+  ...
+  STRESS_TENSOR ANALYTICAL
+  &PRINT
+    &STRESS_TENSOR
+    &END STRESS_TENSOR
+  &END PRINT
+  ...
+&END FORCE_EVAL
+</code>
+<note tip>Your calculation should be set up in such a way that forces are being calculated:
+e.g. ''RUN_TYPE'' set to ''GEO_OPT'' or ''ENERGY_FORCE''; instead ''RUN_TYPE ENERGY'' won't work!</note>
+===== How do I restart a calculation? =====
+There are two restart files usually produced by a run:
+  * a binary file, typically ''//<PROJECT>//-RESTART.wfn'', which contains the WFs coefficients.
+  * a ASCII file, typically ''//<PROJECT>//-1.restart'', which has the same structure as the input file with all the keyword specified (in case with the default values).
+To employ the WFs restart file it's enough to change in the input file ''SCF_GUESS ATOMIC'' or ''SCF_GUESS RANDOM''
+into ''SCF_GUESS RESTART'' (see the [[https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/DFT/SCF.html#SCF_GUESS|manual]]).
+Instead, to restart e.g. the positions of the atoms along a GEO_OPT run, you should add
+a [[https://manual.cp2k.org/trunk/CP2K_INPUT/EXT_RESTART.html|new section]] to the input file:
+<code>
+&EXT_RESTART
+    RESTART_FILE_NAME <PROJECT>-1.restart
+&END EXT_RESTART
+</code>
+where you should replace ''//<PROJECT>//'' with the content of your ''PROJECT_NAME'' (eventually aliased to ''PROJECT'') keyword in section ''&GLOBAL''.