trapz: Calculate the area under a sampled curve (or set of curves).

In neuroconductor/ANTsR: ANTs in R: Quantification Tools for Biomedical Images

Description

Given a vector (or a matrix) representing a curve (or set of curves, columnwise), the area (or set of areas) is calculated using the trapezoidal rule.

Usage

trapz(x, y)

Arguments

x	vector of samples for the dependent variable.
y	vector or matrix of samples for the independent variable. In the case of the latter, curves are organized column-wise.

Value

area (areas) under the sampled curve (curves).

Author(s)

Tustison NJ

Examples

x <- seq( 0, 1, by = 0.0001 )
y <- exp( x )

# Compare with true area of exp( 1 ) - 1 = 1.718282...
areaEstimate <- trapz( x, y )

neuroconductor/ANTsR documentation built on Oct. 11, 2020, 8:14 a.m.