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Daniel Prager
Modern, Object-Oriented Math(s)-Based Algorithms.
These classes and test applications implement some math structures, written entirely in Eiffel.
Class FOURIERIZABLE_VECTOR represents a vector with two "forms", corresponding to (say) time-domain and frequency-domain. The 'transform' feature tells the vector to switch between these forms. This is implemented using a fast-fourier transform. Additionally, vector operations are only permitted if they are in the same form.
Class COMPLEX provides the standard mathematical functions (trig, log, inverses etc) extended to take complex arguments, with zealous postconditions.