getTwist: Estimate the twist in a bullet land

In heike/x3prplus: Algorithms for Matching Bullet Lands

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, transpose = FALSE, twistlimit = NULL,
  cutoff = 0.75)

Arguments

path	to a file in x3p format
bullet	data in x3p format as returned by function read.x3p
transpose	If TRUE, transpose the matrix
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)

heike/x3prplus documentation built on May 17, 2019, 3:24 p.m.