primitive {gsignal}

Primitive

Description

Calculate the indefinitive integral of a function.

Usage

primitive(FUN, t, C = 0)

Arguments

FUN

the function to calculate the primitive of.

t

points at which the function FUN is evaluated, specified as a vector of ascending values

C

constant of integration. Default: 0

Details

This function is a fancy way of calculating the cumulative sum.

Value

Vector of integrated function values.

Author(s)

Juan Pablo Carbajal.
Conversion to R by Geert van Boxtel, [e-mail]

See Also

cumsum

Examples

f <- function(t) sin(2 * pi * 3 * t)
t <- c(0, sort(runif(100)))
F <- primitive (f, t, 0)
t_true <- seq(0, 1, length.out = 1e3)
F_true <- (1 - cos(2 * pi * 3 * t_true)) / (2 * pi * 3)
plot (t, F, xlab = "", ylab = "")
lines (t_true, F_true, col = "red")
legend("topright", legend = c("Numerical primitive", "True primitive"),
  lty = c(0, 1), pch = c(1, NA), col = 1:2)