Interpolation and fitting

Polynomial interpolation
1D polynomial interpolation

Rational interpolation
1D rational interpolation

Spline interpolation and fitting
1D spline interpolation and fitting

Bilinear spline interpolation
Bilinear spline interpolation

Bicubic spline interpolation/fitting
Large-scale bicubic spline interpolation/fitting (regular and scattered datasets)

Least squares fitting (linear/nonlinear)
Least squares fitting (linear/nonlinear)

Fast RBF interpolation/fitting
Scattered interpolation/fitting in O(N*logN) time.

Introduction to RBF's
Introductory course to RBF interpolation

OUTDATED ARTICLE: inverse distance weighting interpolation/fitting
Obsolete algorithm which was superseded by RBFs

OUTDATED ARTICLE: bilinear and bicubic spline interpolation
Bilinear and bicubic spline interpolation