The purpose of QtiPlot was to develop a free, platform independent clone of
Origin. The result is still far away from its model, but there's a "wish to"
list that is being constantly worked on.

Features:
   * 2D and 3D Plots
   * Powerful and versatile spreadsheets and calculations in column-logic
   * Easy ASCII-Import/Export of single or multiple files
   * Linear and non-linear y=f(x) curve fitting and estimation of statistical
errors of the fit-parameters
   * Multi-peak fitting with Gaussian and Lorentzian peak profiles
   * Data analysis: statistics, sorting, FFT, data smoothing (Savitzky-Golay,
FFT smoothing, and moving window average), data filtering (low/high/band pass
and band block filters), convolution/deconvolution, correlation, interpolation,
numerical integration/differentiation, etc...
   * Matrices optimized for 3D plotting
   * Templates support: all the settings for plots (2D/3D), tables and matrixes
can be saved to ASCII files and restored later on for a fast editing process
   * Project files based on folders, a powerful project explorer with extensive
built-in features: drag and drop, searching facilities, etc...

WWW: http://soft.proindependent.com/qtiplot.html