# Extracting an equation from an interpolated function

Im trying to use LibraryLink to do some calculations in C but part of the expression i want to calculate is an Interpolating Function. C cant use that obviously so I'm trying to shift it to a data type that i can use.

So first question, does an interpolated function exist as an equation as in y = ax^2 + bx + c, if yes, can that be extracted, if not, can it be used with something like InterpolatingPolynomial to create an equation.

The most obvious solution is to create an interpolating polynomial to begin with but the existing code is quite extensive so it would involve a lot of modifications, which is fine i guess but i thought i would check if anyone had any ideas first.

• You can also extract the underlying data from an InterpolatingFunction and re-implement the interpolation method in C. Try ifun["Methods"] or google for "InterpolatingFunctionAnatomy". – Szabolcs Jan 12 '15 at 23:27