Evaluate Expression Involving Function Arrays
Evaluates any expression involving one or more function arrays
(fasp objects) and returns another function array.
eval.fasp(expr, envir, dotonly=TRUE)
expr |
An expression involving the names of objects of class |
envir |
Optional. The environment in which to evaluate the expression,
or a named list containing |
dotonly |
Logical. Passed to |
This is a wrapper to make it easier to perform pointwise calculations with the arrays of summary functions used in spatial statistics.
A function array (object of class "fasp") can be regarded as a matrix
whose entries are functions. Objects of this kind
are returned by the command alltypes.
Suppose X is an object of class "fasp".
Then eval.fasp(X+3) effectively adds 3 to the value of
every function in the array X, and returns
the resulting object.
Suppose X and Y are two objects of class "fasp"
which are compatible (for example the arrays
must have the same dimensions). Then
eval.fasp(X + Y) will add the corresponding functions in
each cell of the arrays X and Y,
and return the resulting array of functions.
Suppose X is an object of class "fasp"
and f is an object of class "fv".
Then eval.fasp(X + f) will add the function f
to the functions in each cell of the array X,
and return the resulting array of functions.
In general, expr can be any expression involving
(a) the names of objects of class "fasp" or "fv",
(b) scalar constants, and (c) functions which are vectorised.
See the Examples.
First eval.fasp determines which of the variable names
in the expression expr refer to objects of class "fasp".
The expression is then evaluated for each cell of the array
using eval.fv.
The expression expr must be vectorised.
There must be at least one object of class "fasp" in the expression.
All such objects must be compatible.
Another object of class "fasp".
Adrian Baddeley Adrian.Baddeley@curtin.edu.au
and Rolf Turner r.turner@auckland.ac.nz
K <- alltypes(amacrine, "K") # expressions involving a fasp object eval.fasp(K + 3) L <- eval.fasp(sqrt(K/pi)) # expression involving two fasp objects D <- eval.fasp(K - L) # subtracting the unmarked K function from the cross-type K functions K0 <- Kest(unmark(amacrine)) DK <- eval.fasp(K - K0) ## Use of 'envir' S <- eval.fasp(1-G, list(G=alltypes(amacrine, 'G')))
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