POLY Function
Standard Library function that evaluates a polynomial function of a variable.
Usage
result = POLY(x, coefficients)
Input Parameters
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.
Returned Value
result — The values calculated from the polynomial function of x.
Keywords
None.
Discussion
POLY evaluates a polynomial function of a variable according to the formula:
result = c0 + c1x + c2x2 + ... + cn–1xn–1
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.
Example
x = 2
c = [1, 2, 3]
func = POLY(x, c)
PRINT, func
; PV-WAVE prints: 17
