Thank you very much as i am on windows, unfortunally there is no gridflow. - and i tried to make sqrt from pd, but it does not like -1.
thanks again der.brandt > On Fri, 28 Aug 2009, bra...@subnet.at wrote: > >> how is it possible to calculate with imaginary numbers in PD besides the >> fft stuff. > > basically, if you know that something is an imaginary number, you can use > a real number in its place and just remember to multiply by square root of > -1 in your head. > > but if you want to combine real and imaginary numbers, then you need > complex numbers, each of which is a real and an imaginary number. > > let i be sqrt(-1)... then let's say you have two complex numbers, a+bi, > c+di, as four floats. the sum is (a+c)+(b+d)i, that is you add the real > parts together, and add the imaginary parts together. From this, you can > guess how to subtract. The product formula is (a*c-b*d)+(a*d+b*c)i, which > you can often see in Miller's FFT patches as a cluster of four [*~]. > > You can find more such formulas on Wikipedia, PlanetMath, MathWorld, or > other, but if you can't find one or have trouble getting one to work, ask > pd-list again. > > Abstractions could have been made for some of these, especially *, /, exp, > log, but I don't think any such library exists. GridFlow provides those > operations as an external if you need something fast. > > _ _ __ ___ _____ ________ _____________ _____________________ ... > | Mathieu Bouchard, Montréal, Québec. téléphone: +1.514.383.3801 _______________________________________________ Pd-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list