integrateTrapezoid {oce} | R Documentation |
Estimate the integral of one-dimensional function using the trapezoidal rule.
integrateTrapezoid(x, y, type=c("A", "dA", "cA"))
x |
x values, or a single value that is taken as the (constant) difference between x values. |
y |
y values, with length ( |
type |
Flag indicating the desired return value (see “Value”). |
If type="A"
(the default), a single value is returned, containing
the estimate of the integral of y=y(x)
. If type="dA"
, a
numeric vector of the same length as x
, of which the first element
is zer0, the second element is the integral between x[1]
and
x[2]
, etc. If type="cA"
, the result is the cumulative sum
(as in cumsum
) of the values that would be returned for
type="dA"
. See “Examples”.
There is no handling of NA
values.
Dan Kelley
x <- seq(0, 1, length.out=10) # try larger length.out to see if area approaches 2 y <- 2*x + 3*x^2 A <- integrateTrapezoid(x, y) dA <- integrateTrapezoid(x, y, "dA") cA <- integrateTrapezoid(x, y, "cA") print(A) print(sum(dA)) print(tail(cA, 1)) print(integrateTrapezoid(diff(x[1:2]), y)) print(integrateTrapezoid(y))