dump_modify 1 format "%d %d %20.15g %g %g" scale yes dump_modify myDump image yes scale no flush yes dump_modify 1 region mySphere thresh x < 0.0 thresh epair >= 3.2 -dump_modify xtcdump precision 10000 +dump_modify xtcdump precision 10000 +dump_modify 1 every 1000 +dump_modify 1 every v_myVar
Description:
@@ -77,9 +80,30 @@ in the simulation. The same element name can be given to multiple atom types.The every keyword changes the dump frequency originally specified by -the dump command to a new value which must be > 0. The -dump frequency cannot be changed for the dump dcd style. +the dump command to a new value. The every keyword can be +specified in one of two ways. It can be a numeric value in which case +it must be > 0. Or it can be an equal-style variable, +which should be specified as v_name, where "name" is the variable +name. In this case, the variable is evaluated at the beginning of a +run to determine the next timestep at which a dump snapshot will be +written out. On that timestep, the variable will be evaluated again +to determine the next timestep, etc. Thus the variable should return +timestep values. See the stagger() and logfreq() math functions for +equal-style variables, as examples of useful functions +to use in this context. Other similar math functions could easily be +added as options for equal-style variables. When +using the variable option with the every keyword, you also need to +use the first option if you want an initial snapshot written to the +dump file. The every keyword cannot be used with the dump dcd +style.
+For example, the following commands will +write snapshots at timesteps 0,10,20,30,100,200,300,1000,2000,etc: +
+variable s equal logfreq(10,3,10) +dump 1 all atom 100 tmp.dump +dump_modify 1 every v_s first yes +
The first keyword determines whether a dump snapshot is written on
the very first timestep after the dump command is invoked. This will
always occur if the current timestep is a multiple of N, the frequency
diff --git a/doc/dump_modify.txt b/doc/dump_modify.txt
index 03ad9fbca5..16a04f5486 100644
--- a/doc/dump_modify.txt
+++ b/doc/dump_modify.txt
@@ -20,6 +20,7 @@ keyword = {append} or {every} or {flush} or {format} or {image} or {label} or {p
E1,...,EN = element name, e.g. C or Fe or Ga
{every} arg = N
N = dump every this many timesteps
+ N can be a variable (see below)
{first} arg = {yes} or {no}
{format} arg = C-style format string for one line of output
{flush} arg = {yes} or {no}
@@ -43,7 +44,9 @@ keyword = {append} or {every} or {flush} or {format} or {image} or {label} or {p
dump_modify 1 format "%d %d %20.15g %g %g" scale yes
dump_modify myDump image yes scale no flush yes
dump_modify 1 region mySphere thresh x < 0.0 thresh epair >= 3.2
-dump_modify xtcdump precision 10000 :pre
+dump_modify xtcdump precision 10000
+dump_modify 1 every 1000
+dump_modify 1 every v_myVar :pre
[Description:]
@@ -70,8 +73,29 @@ in the simulation. The same element name can be given to multiple
atom types.
The {every} keyword changes the dump frequency originally specified by
-the "dump"_dump.html command to a new value which must be > 0. The
-dump frequency cannot be changed for the dump {dcd} style.
+the "dump"_dump.html command to a new value. The every keyword can be
+specified in one of two ways. It can be a numeric value in which case
+it must be > 0. Or it can be an "equal-style variable"_variable.html,
+which should be specified as v_name, where "name" is the variable
+name. In this case, the variable is evaluated at the beginning of a
+run to determine the next timestep at which a dump snapshot will be
+written out. On that timestep, the variable will be evaluated again
+to determine the next timestep, etc. Thus the variable should return
+timestep values. See the stagger() and logfreq() math functions for
+"equal-style variables"_variable.html, as examples of useful functions
+to use in this context. Other similar math functions could easily be
+added as options for "equal-style variables"_variable.html. When
+using the variable option with the {every} keyword, you also need to
+use the {first} option if you want an initial snapshot written to the
+dump file. The {every} keyword cannot be used with the dump {dcd}
+style.
+
+For example, the following commands will
+write snapshots at timesteps 0,10,20,30,100,200,300,1000,2000,etc:
+
+variable s equal logfreq(10,3,10)
+dump 1 all atom 100 tmp.dump
+dump_modify 1 every v_s first yes :pre
The {first} keyword determines whether a dump snapshot is written on
the very first timestep after the dump command is invoked. This will
diff --git a/doc/variable.html b/doc/variable.html
index 9b5ba793fb..394b536b35 100644
--- a/doc/variable.html
+++ b/doc/variable.html
@@ -34,7 +34,8 @@
x==y, x!=y, xNumber 0.2, 100, 1.0e20, -15.4, etc Thermo keywords vol, pe, ebond, etc Math operators (), -x, x+y, x-y, x*y, x/y, x^y, x==y, x!=y, x Math functions sqrt(x), exp(x), ln(x), log(x), sin(x), cos(x), tan(x), asin(x), acos(x), atan(x), ceil(x), floor(x), round(x), ramp(x,y) Math functions sqrt(x), exp(x), ln(x), log(x), sin(x), cos(x), tan(x), asin(x), acos(x), atan(x), ceil(x), floor(x), round(x), ramp(x,y), stagger(x,y), logfreq(x,y,z) Group functions count(ID), mass(ID), charge(ID), xcm(ID,dim), vcm(ID,dim), fcm(ID,dim), bound(ID,dir), gyration(ID), ke(ID), angmom(ID,dim), inertia(ID,dimdim), omega(ID,dim) Region functions count(ID,IDR), mass(ID,IDR), charge(ID,IDR), xcm(ID,dim,IDR), vcm(ID,dim,IDR), fcm(ID,dim,IDR), bound(ID,dir,IDR), gyration(ID,IDR), ke(ID,IDR), angmom(ID,dim,IDR), inertia(ID,dimdim,IDR), omega(ID,dim,IDR) Atom values mass[i], type[i], x[i], y[i], z[i], vx[i], vy[i], vz[i], fx[i], fy[i], fz[i]
Ramp(x,y) uses the current timestep to generate a scalar value:
-