Simple tool for nonlinear least squares with arithmetic expressions and symbolic differentiation.

Curve fitting	Fourier series	Linear piecewise approximation	Genetic curve fitting

Theory

Symbol "x" is reserved for independent variable, every other identifier will be treated as an unknown parameter.

You can assign initial value for parameter with curly brackets, i. e. "p1{3.25}".

List of supported mathematical functions:

• sin(x)
• cos(x)
• tan(x)
• cot(x)
• sinc(x)
• sinh(x)
• cosh(x)
• tanh(x)
• coth(x)
• asinh(x)
• acosh(x)
• atanh(x)
• acoth(x)
• atan(x)
• asin(x)
• acos(x)
• acot(x)
• erf(x)
• exp(x)
• pow(x,power)
• pi()
• e()
• smoothstep(x)
• step(x)
• sign(x)
• sqrt(x)
• ln(x)
• lg(x)
• log(base,x)
• min(a,b)*
• max(a,b)*
• abs(a,b)*

* - uses numerical differentiation, because they are not continuous

TODO

• Web workers
• Parameters for genetic curve fitting
• Add optimization methods