Hello,
it would be nice to have an interpreter for mathematical expressions so that
functions may be defined at runtime.
Example for f(x):
ExpInter ei = new ExpInter();
ei.setFunction("ln(3*sin(2*x)+3)");
// Plot the function:
for (double x=0.0;x<3.0;x+=0.1) {
y = ei(x);
// ... do something useful with x,y
}
Can be expanded to f(x,y) or functions wit params f(x,p1,p2,p3):
ei.setFunction("1+p0*x-5*p1*(p2+7)*p3/x");
double[] params = { 1.0, 2.0, 4.0, -1 };
ei.setParams(params);
// plot ....
If the interpreter implements UnivariateFunction it would be even nicer:
ExpInter function = new ExpInter("x^3-2*x^2+x-27");
double root = solver.solve(99999, function, 0.0, 5.0);
System.out.println("root is " + root + " / " + function.value(root));
function.setFunction("sin(x)");
root = solver.solve(99999, function, 3.0, 4.0);
System.out.println("root is " + root + " / " + function.value(root));
Result:
de.guenther.roots.RegulaFalsi:
[java] root is 3.7009897720655234 / 0.0
[java] root is 3.141592653589793 / 1.2246467991473532E-16
I may post my interpreter.
Kind regards
Detlef Guenther
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