Polynomial basis

Orthogonal polynomial expansion of a linear term based on poly

Usage

Poly(x, degree)

Arguments

x

a numeric vector at which to evaluate the polynomial. Missing values are not allowed in x.

degree

the degree of the polynomial. Must be less than the number of unique points.

Value

an instance of class Poly extending ParametricBasis

See also

poly

Examples

# Create a 3rd degree polynomial basis
x_vals <- c(1, 2, 3, 4, 5, 6)
poly_basis <- Poly(x_vals, degree = 3)
print(poly_basis$y)
#>               1          2          3
#> [1,] -0.5976143  0.5455447 -0.3726780
#> [2,] -0.3585686 -0.1091089  0.5217492
#> [3,] -0.1195229 -0.4364358  0.2981424
#> [4,]  0.1195229 -0.4364358 -0.2981424
#> [5,]  0.3585686 -0.1091089 -0.5217492
#> [6,]  0.5976143  0.5455447  0.3726780
#> attr(,"coefs")
#> attr(,"coefs")$alpha
#> [1] 3.5 3.5 3.5
#> 
#> attr(,"coefs")$norm2
#> [1]  1.00000  6.00000 17.50000 37.33333 64.80000
#> 
#> attr(,"degree")
#> [1] 1 2 3
#> attr(,"class")
#> [1] "poly"   "matrix"