Standard Library function that evaluates a polynomial function of a variable.

x — The variable that is evaluated. May be a scalar or array.

coefficients — A vector containing one more element than the degree of the polynomial function. These elements are the coefficients of the polynomial equation that is used by POLY.

result — The values calculated from the polynomial function of x.

None.

POLY evaluates a polynomial function of a variable according to the formula:

where n is the dimension of the polynomial c, and c0 through cn–1 are the coefficients.

POLY returns a variable with the same dimensions as x. Each element of the result is equal to the computed value of c0 + c1x + c2x2 + cixi for each element of x.

The POLY function can be used in conjunction with POLY_FIT and POLYFITW, which both return the coefficients of a polynomial function fitted through data.

x = 2

c = [1, 2, 3]

func = POLY(x, c)

PRINT, func

; PV-WAVE prints: 17

POLY_2D, POLY_FIT, POLYFITW, LAGRANGE