int2 {rmutil}

Vectorized Two-dimensional Numerical Integration

Description

int performs vectorized numerical integration of a given two-dimensional function.

Usage

int2(f, a=c(-Inf,-Inf), b=c(Inf,Inf), eps=1.0e-6, max=16, d=5)

Arguments

f

The function (of two variables) to integrate, returning either a scalar or a vector.

a

A two-element vector or a two-column matrix giving the lower bounds. It cannot contain both -Inf and finite values.

b

A two-element vector or a two-column matrix giving the upper bounds. It cannot contain both Inf and finite values.

eps

Precision.

max

The maximum number of steps, by default set to 16.

d

The number of extrapolation points so that 2k is the order of integration, by default set to 5; d=2 is Simpson's rule.

Value

The vector of values of the integrals of the function supplied.

Author(s)

J.K. Lindsey

Examples

f <- function(x,y) sin(x)+cos(y)-x^2
int2(f, a=c(0,1), b=c(2,4))
#
fn1 <- function(x, y) x^2+y^2
fn2 <- function(x, y) (1:4)*x^2+(2:5)*y^2
int2(fn1, c(1,2), c(2,4))
int2(fn2, c(1,2), c(2,4))
int2(fn1, matrix(c(1:4,1:4),ncol=2), matrix(c(2:5,2:5),ncol=2))
int2(fn2, matrix(c(1:4,1:4),ncol=2), matrix(c(2:5,2:5),ncol=2))