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 \(x^iy^j\). 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.

none really

# NOT RUN { 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)) # }