getTwist {bulletr}

Estimate the twist in a bullet land

Description

Estimation of the twist in a barrel follows roughly the process described by Chu et al (2010). At the moment, twist is estimated from a single land - but the twist should be the same for the whole barrel. Therefore all lands of the same barrel should have the same twist. A note on timing: at the moment calculating the twist rate for a bullet land takes several minutes. XXX TODO XXX make the different methods a parameter. Also, accept other input than the path - if we start with the flattened bulletland we get results much faster.

Usage

getTwist(path, bullet = NULL, twistlimit = NULL, cutoff = 0.75)

Arguments

path

to a file in x3p format

bullet

data in x3p format as returned by function read_x3p

twistlimit

Constraint the possible twist value

cutoff

Use this for the quantile cutoff

Value

numeric value estimating the twist

Examples

## Not run: 
# execution takes several minutes
load("data/b1.rda")
twist <- getTwist(path="barrel 1 bullet 1", bullet = b1, twistlimit=c(-2,0)*1.5625)

## End(Not run)