hi guys, it seems that the problems i had with the prefactors involved in the sine transformation were more or less caused by my ignorance and a lack of knowledge (as usually) :) just in case somebody would stumble upon this issue in the future, i will summarize my 'findings'. the function for forward/inverse discrete sine transformation are themselves normalized to the number of sampling points. therefore, F' = DST(f) iDST(F') = f however, to get the real sine transformation of f, it's necessary to multiply the abovementioned expression with the step size in the real space F = DST(f) dr this expression leads to the equivalent of the sine transformation, where the 2/pi normalization is carried out in the inverse transformation. for the equivalent of the unitary sine transform, it's needed to further multiply with sqrt(2/pi) the same then applies for the inverse transformation, so in the end x = 2/pi dr dk iDST(DST(f)) but the dr dk product brings in the number of sampling points. for the sine transformation, dk = pi/(Ndr) and, therefore, x = 2/pi pi/N iDST(DST(f)) = 2/N f in order to get the function f back, it's necessary to multiply the inverse FT with N/2. this essentially solves the question posted in sine transformation weirdness 'thread' as well. -- Lubos _@_" http://www.lubos.vrbka.net