Define a multivariate polynomial.

mp is a smart function which attempts to create a formal mpoly object from a character string containing the usual representation of a multivariate polynomial.

make_indeterminate_list(vars)

mp(string, varorder, stars_only = FALSE)

Arguments

vars	a character vector of indeterminates
string	a character string containing a polynomial, see examples
varorder	(optional) order of variables in string
stars_only	if you format your multiplications using asterisks, setting this to TRUE will reduce preprocessing time

Value

An object of class mpoly.

See also

mpoly()

Examples

( m <- mp("x + y + x y") )
#> x  +  y  +  x y
is.mpoly( m )
#> [1] TRUE
unclass(m)
#> [[1]]
#>    x coef 
#>    1    1 
#> 
#> [[2]]
#>    y coef 
#>    1    1 
#> 
#> [[3]]
#>    x    y coef 
#>    1    1    1 
#> 


mp("x + 2 y + x^2 y + x y z")
#> x  +  2 y  +  x^2 y  +  x y z
mp("x + 2 y + x^2 y + x y z", varorder = c("y", "z", "x"))
#> x  +  2 y  +  y x^2  +  y z x

( ms <- mp(c("x + y", "2 x")) )
#> x  +  y
#> 2 x
is.mpolyList(ms)
#> [1] TRUE


gradient( mp("x + 2 y + x^2 y + x y z") )
#> 2 x y  +  y z  +  1
#> x^2  +  x z  +  2
#> x y
gradient( mp("(x + y)^10") )
#> 10 x^9  +  90 x^8 y  +  360 x^7 y^2  +  840 x^6 y^3  +  1260 x^5 y^4  +  1260 x^4 y^5  +  840 x^3 y^6  +  360 x^2 y^7  +  90 x y^8  +  10 y^9
#> 10 x^9  +  90 x^8 y  +  360 x^7 y^2  +  840 x^6 y^3  +  1260 x^5 y^4  +  1260 x^4 y^5  +  840 x^3 y^6  +  360 x^2 y^7  +  90 x y^8  +  10 y^9

# mp and the print methods are kinds of inverses of each other
( polys <- mp(c("x + y", "x - y")) )
#> x  +  y
#> x  -  y
strings <- print(polys, silent = TRUE)
strings
#> [1] "x  +  y" "x  -  y"
mp(strings)
#> x  +  y
#> x  -  y