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snaptrim - select a subset of the snapshot frames in a file


snaptrim in=in_file out=out_file [parameter=value] ...


snaptrim reads snapshot(5NEMO) data from in and copies a subset of the frames to out. Frames may be selected by specifying either a time range, or sampling frequencies for particle and diagnostic frames.

snaptrim has the option of assuming the input file contains a sorted series (in time) of snapshots, in which case the scanning stops immediately after the last needed snapshot is written. (see keyword checkall= below).


The following parameters are recognized:
Input data is read from in_file, in snapshot(5NEMO) format. Default: none.
Selected frames are written to out_file. If the name contains a valid mstropen(3NEMO) formatted name, the output file will be split over multiple files. Default: none.
Select frames with time values within time_range, which is of a form such as 1.0:1.5,2.5,3.0. A special format is allowed to select the Nth snapshot using times=#N, where the first snapshot is counted as 1. Special values are first, last and all. If timefuzz=nearest (see below) is used, time_range must contain just a single value. Default: all.
Select one out of every interval particle frames within time_range; if 0, select none. Default: 1, which selects all.
Select one out of every interval diagnostic frames within time_range; if 0, select none. Default: 1, which selects all.
Set it to true if you don’t want history records to be in the output file. Default: false.
Set it to true if you really want to be sure all snapshots are checked if to be copied. This keyword must be set to true when the input snapshot is not sorted in time. By setting it to false, it can speed up scanning enormously. Default: false.
Fuzzyness allowed in comparing times requested for output, and actual times in snapshot. The special string value "nearest" is also allowed to output the snapshot closest to the requested time. In this case, the times= keyword cannot contain ranges.

See Also

snapsample(1NEMO) , snapmask(1NEMO) , snapshot(5NEMO)


For times=last you should not use a pipe in the input stream, i.e. in=-.


Joshua E. Barnes

Update History

xx-xxx-8x    V1.0 Created    JEB
xx-mar-89    V1.2 keyword amnesia= added    JEB
12-apr-89    V1.3 keyword checkall= added    PJT
5-maa-98    V1.6 added first/last times    PJT
14-sep-02    V2.0 support multiple output files    PJT
31-dec-03    V2.1 timefuzz= implemented    PJT

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