interp_trig, an Octave code which interactively uses n equally spaced nodes in the interval [a,b] to interpolate a function f(x) with a trigonometric function.
The user enters a formula for f(x), and the values of a and b, and the number of interpolation points n.
The program computes the corresponding interpolating trigonometric function and returns its value at 101 points in [a,b].
The program can be invoked by a function call, in which case the string specifying f(x) must be quoted:
[ xp, yp ] = interp_trig ( 'x^2', -1, 3, 11 )
or, if called with no arguments, it will request them:
[ xp, yp ] = interp_trig ( );
Enter function formula, like x^2: x^2
Enter left limit, a: -1
Enter right limit, b: 3
Enter number of interpolation points: 11
The function is specified as a string which is either:
The string should not contain any spaces between symbols, except when it is passed as a function argument in quotes.
It is not necessary to use the "dot" notation for expressions involving '*', '/', or '^', but it doesn't hurt either.
Examples of function specifications:
x^2
x.^2
3/(x^4+5*x-6)
sin(7*x)*sqrt(x)/8
wiggle(x) <-- where "wiggle.m" is a user-provided M file.
The information on this web page is distributed under the MIT license.
interp_trig is available in a MATLAB version and an Octave version.
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