multipol-package {multipol} | R Documentation |
Various tools to manipulate and combine multivariate polynomials
Package: | multipol |
Type: | Package |
Version: | 1.0 |
Date: | 2008-01-24 |
License: | GPL |
Basically, coerce an array to a multivariate polynomial (a
“multipol”) using as.multipol()
.
Taking a matrix a
as an example, because this has two dimensions
it may be viewed as a bivariate polynomial with a[i,j]
being the
coefficient of x^i.y^j. Note the off-by-one issue; see
?Extract
.
Multivariate polynomials of arbitrary arity are a straightforward generalization using appropriately dimensioned arrays.
Arithmetic operations “+
”,“-
”,
“*
”, “^
” operate as though their arguments
are multivariate polynomials.
Even quite small multipols are computationally intense; many coefficients have to be calculated and each is the sum of many terms.
The package would benefit enormously by being able to use a sparse array class.
Robin K. S. Hankin
Maintainer: <r.hankin@noc.soton.ac.uk>
none really
ones(2)*linear(c(1,-1)) # x^2-y^2 ones(2)*(ones(2,2)-uni(2)) # x^3+y^3 a <- as.multipol(matrix(1:12,3,4)) a a[1,1] <- 11 f <- as.function(a*a) f(c(1,pi))