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