Truncate the timespan of a BirdFlow model

truncate_birdflow() Eliminates marginals and/or transitions from a BirdFlow model and adjusts other aspects of the model so that it only covers part of a year. The intent is to reduce object size and processing time when only part of the year is of interest.

Usage

truncate_birdflow(bf, ...)

Arguments

bf

A BirdFlow object.

...

Arguments passed on to lookup_timestep_sequence

season

a season name, season alias, or "all". See lookup_season_timesteps() for options.

start

The starting point in time specified as a timestep, character date, or date object.

end

The ending point in time as a date or timestep.

direction

Either "forward" or "backward" defaults to "forward" if not processing dates. If using date input direction is optional and is only used to verify the direction implicit in the dates.

season_buffer

Only used with season input. season_buffer is passed to lookup_season_timesteps() and defaults to 1; it is the number of timesteps to extend the season by at each end.

n_steps

Alternative to end The end will be n_steps away from start in direction; and the resulting sequence will have n_step transitions and n_steps + 1 timesteps.

Value

A BirdFlow model that only contains information about transitions for a subset of the year as specified by ....

Details

The model timesteps will always be numbered from 1 to n_timesteps() and so likely will not be consistent with weeks of the year with the truncated model.

Currently it's possible to truncate both a fitted model and a model produced by preprocess_species() but I have yet to create a way to export a preprocessed model after truncating it (independently of preprocess_species()) or to truncate during preprocessing. So currently the utility is limited to reducing the size of fitted models.

It's possible to truncate a model over the year boundary but routes generated from such a model will not plot correctly so it's not recommended; see issue #120.