dual {salad} | R Documentation |
Dual objects
Description
Create a dual object
Usage
dual(x, varnames, dx, constant = FALSE)
Arguments
x |
a numeric object (vector, matrix, or array) |
varnames |
(optional) the name of the variables in x |
dx |
(optional) a list of derivatives for the elements of x |
constant |
if 'TRUE', then a constant is returned. |
Details
The basic usage is dual(x)
which will create an object of
class 'dual' with unit derivatives in each of its components. The variable
names will be derived from the names of x
, or generated in the form
x1
, x2
, etc.
Another possible usage is dual(x, varnames = c('x1', 'x2'), constant = TRUE)
which returns an object with null derivatives in x1
and x2
.
Finally, a list of derivatives can be defined using option dx
.
Value
an object of class 'dual'
Examples
# simple usage
x <- dual( c(1,2) )
x
d(x)
x <- dual(matrix(c(1,2,3,4), 2, 2))
x
d(x, "x1.1")
# using an object with names
x <- dual( c(a = 1, b = 2) )
x
d(x)
# generate a constant
x <- dual(1, varnames = c("x1", "x2"), constant = TRUE)
# specify dx
x <- dual(c(1,2), dx = list(x1 = c(1,1)))
x
d(x)
# this is equivalent to :
x <- dual(1)
x <- c(x, x + 1)
x
d(x)
[Package salad version 1.0 Index]