I wonder if there is a multi-dim interpolation algorithm in ROOT? I found only ROOT::Math::Polynomial , ROOT::Math::Interpolator classes, but they are only 1Dim.
I need to interpolate a function of four variables F(x,y,z,w). Is there a possibility to do it?
For 3D data we have the function TH3::Interpolate which does linear interpolation. In your case you might try to use the TMultiDimFit class which performs a fit using polynomials to multi-dimensional data.
See root.cern.ch/root/html/TMultiDimFit.html