stepfun
Compute a Step Function
Description
Computes a left- or right-continuous step function.
Usage
stepfun(x, y, f = as.numeric(right), ties = "ordered", right = FALSE)
is.stepfun(x)
knots(Fn, ...)
## S3 method for class 'stepfun':
knots(Fn, ...)
## S3 method for class 'stepfun':
summary(object, ...)
as.stepfun(x, ...)
## Default S3 method:
as.stepfun(x, ...)
Arguments
| x |
For stepfun, a numeric vector giving the breakpoints (knots) of the step function.
x must be sorted by increasing order and have at least one element.
indicates points of plateau levels.
For as.stepfun and is.stepfun, x is any object.
For print.stepfun, x is an object that inherits from "stepfun".
|
| y |
a numeric vector, with length 1 + length(x),
indicating the possible values of the step function.
If right is FALSE the value at x[i]
will be y[i+1], if TRUE it will be y[i].
|
| f |
A number between 0 and 1 indicating how the levels of the plateaus
between jump points should be calculated. For a plateau between
jump points level will be 1-f times the value at the left jump
point plus f times the value at the right jump point.
The plateau to the left of x[1] will have value y[1],
that to the left of x[length(x)] will have value y[length(x)+1],
regardless of the value of f or right.
|
| ties |
arguments to be passed to function "approxfun".
|
| right |
a logical value, if TRUE, the value at x[i] will be y[i],
otherwise y[i+1].
|
| Fn |
an object inheriting from "stepfun".
|
| digit |
the maximum number of digits after the decimal point to print.
|
| ... |
additional arguments to be passed to or from future functions.
|
Value
| stepfun | returns a function of one argument v, which
performs the interpolation specified.
|
| is.stepfun |
returns TRUE if x is a function and inherits from "stepfun".
|
| knots |
returns a vector containing knots (breakpoints) of a stepfun object.
|
| print.stepfun |
returns x, with the invisible set to prevent reprinting.
|
| summary.stepfun |
invisibly returns NULL.
|
| as.stepfun | returns a stepfun object implied by its input.
This is a generic function and the basic methods do nothing useful:
the default method gives an error and the stepfun method returns
its input.
|
See Also
Examples
y0 <- c(1, 2, 3)
sfun0 <- stepfun(c(4, 5), c(11, 12, 17), f = 0)
sfun0(c(3.7, 4, 4.2, 5, 5.1))
is.stepfun(sfun0)
knots(sfun0)
print(sfun0)