INTERPOLATE_GRID

Interpolate a smooth function stored on a grid onto a grid with a smaller grid spacing.

This action takes a function evaluated on a grid as input and can be used to interpolate the values of that function on to a finer grained grid. The interpolation within this algorithm is done using splines.

Compulsory keywords
 STRIDE ( default=1 ) the frequency with which the data should be collected and added to the quantity being averaged CLEAR ( default=0 ) the frequency with which to clear all the accumulated data. The default value of 0 implies that all the data will be used and that the grid will never be cleared GRID the action that creates the input grid you would like to use
Options
 SERIAL ( default=off ) do the calculation in serial. Do not parallelize LOWMEM ( default=off ) lower the memory requirements TIMINGS ( default=off ) output information on the timings of the various parts of the calculation UNORMALIZED ( default=off ) output the unaveraged quantity/quantities. LOGWEIGHTS list of actions that calculates log weights that should be used to weight configurations when calculating averages COMPONENT if your input is a vector field use this to specifiy the component of the input vector field for which you wish to use GRID_BIN the number of bins for the grid GRID_SPACING the approximate grid spacing (to be used as an alternative or together with GRID_BIN)
Examples

The input below can be used to postprocess a trajectory. It calculates a HISTOGRAM as a function the distance between atoms 1 and 2 using kernel density estimation. During the calculation the values of the kernels are evaluated at 100 points on a uniform grid between 0.0 and 3.0. Prior to outputting this function at the end of the simulation this function is interpolated onto a finer grid of 200 points between 0.0 and 3.0.

x: DISTANCE ATOMS=1,2
hA1: HISTOGRAM ARG=x GRID_MIN=0.0 GRID_MAX=3.0 GRID_BIN=100 BANDWIDTH=0.1
ii: INTERPOLATE_GRID GRID=hA1 GRID_BIN=200
DUMPGRID GRID=ii FILE=histo.dat