functions in cheby.i -
cheby_deriv
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cheby_deriv(fit) returns Chebyshev fit to the derivative of the function of the input Chebyshev FIT. | |
SEE ALSO: | cheby_fit, cheby_integ |
cheby_eval
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cheby_eval(fit, x) evaluates the Chebyshev fit (from cheby_fit) at points X. the return values have the same dimensions as X. | |
SEE ALSO: | cheby_fit |
cheby_fit
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fit = cheby_fit(f, interval, n) or fit = cheby_fit(f, x, n) returns the Chebyshev fit (for use in cheby_eval) of degree N to the function F on the INTERVAL (a 2 element array [a,b]). In the second form, F and X are arrays; the function to be fit is the piecewise linear function of xp interp(f,x,xp), and the interval of the fit is [min(x),max(x)]. The return value is the array [a,b, c0,c1,c2,...cN] where [a,b] is the interval over which the fit applies, and the ci are the Chebyshev coefficients. It may be useful to use a relatively large value of N in the call to cheby_fit, then to truncate the resulting fit to fit(1:3+m) before calling cheby_eval. | |
SEE ALSO: |
cheby_eval,
cheby_integ,
cheby_deriv,
cheby_poly |
cheby_integ
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cheby_integ(fit) or cheby_integ(fit, x0) returns Chebyshev fit to the integral of the function of the input Chebyshev FIT. If X0 is given, the returned integral will be zero at X0 (which should be inside the fit interval fit(1:2)), otherwise the integral will be zero at x=fit(1). | |
SEE ALSO: | cheby_fit, cheby_deriv |
cheby_poly
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cheby_poly(fit) returns coefficients An of x^n as [A0, A1, A2, ..., An] for the given FIT returned by cheby_fit. You should only consider actually using these for very low degree polynomials; cheby_eval is nearly always a superior way to evaluate the polynomial. | |
SEE ALSO: | cheby_fit |