On Sat, 29 Aug 2009, brandt@subnet.at wrote:
and i tried to make sqrt from pd, but it does not like -1.
I'm sorry, I didn't explain this one. In the formulas I gave, "i" represents square root of -1, but you can't use that as a number in pd because pd only supports plain floats and not complex floats. But a non-complex number system can be used to make a complex number system, and the formulas are usually not very long.
A float can only be half of the data of a complex number. It's called complex because it has two parts. The second float stands for the part that is a multiple of "i", and the first float stands for the part that is not. It's also often considered as a 2-D vector with extra operators, with the x (cosine) standing for the real part, and the y (sine) standing for the imaginary part.
http://en.wikipedia.org/wiki/Complex_numbers#The_complex_plane
But don't try to read the whole wikipedia articles on math topics, they're huge and contain much stuff you don't need.
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard, Montréal, Québec. téléphone: +1.514.383.3801