Trapezoidal integration with limits.

Source: R/utils.R

Compute the area of a function with values y at the points x within given limits.

trapz_limits(x, y, lower, upper)

Arguments

x

x-coordinates of points on the x-axis.
y

Function values associated with the x-coordinates.
lower

Lower integration boundary.
upper

Upper integration boundary.

Value

Area under the curve defined by the (x, y)-tuples.

Examples

x <- 0:5
y <- c(1, 4, 2, 3, 3, 0)

trapz_limits(x, y, -2, 10)

#> [1] 12.5

trapz_limits(x, y, -2, -1)

#> [1] 0

trapz_limits(x, y, -2, .4)

#> [1] 0.64

trapz_limits(x, y, .4, .7)

#> [1] 0.795

trapz_limits(x, y, .4, 3.6)

#> [1] 9.16

trapz_limits(x, y, .4, 7)

#> [1] 11.86

trapz_limits(x, y, 6, 7)

#> [1] 0

if (FALSE) {
# throws an error
trapz_limits(x, y, 4, 3)
}