From: Ariel Rokem <arokem@be...>  20100210 01:22:48

Hi  mea culpa  as pointed out by a colleague (and documented in the help document for "hanning" in Matlab), this function produces the same window, but without the first and last zeroweighted samples. Cheers  Ariel On Tue, Feb 9, 2010 at 4:58 PM, Ariel Rokem <arokem@...> wrote: > Hi everyone, > > Mystery solved (I think)! It turns out that matlab has two functions, one > called "hann" and the other called "hanning". They both purport to produce > the hanning window, but they produce two (slightly) different things. Only > one of these (the one given by "hann") actually produces the hanning window > as it is defined in the standard reference on this (Harris 1978. And also > Wikipedia ;D). When using the "hann" function in Matlab in this little > experiment, the difference between the python and the matlab results, is on > the order of %10e6. I think I am willing to live with that. > > The only mystery that remains (I think) is  what is Matlab's "hanning" > supposed to be doing? Are there two different windows: hann and hanning (not > "hamming"  I know that's a different one)? > > Cheers, > > Ariel > > > On Mon, Feb 8, 2010 at 9:32 AM, Ariel Rokem <arokem@...> wrote: > >> Hi  >> >> the maximal difference in this case is of about 6 (units?), which is an >> approximately 50% difference. This is in one point in the spectrum which has >> a relatively small value  the maximal peaks in the spectra are on the order >> of 1200, so in the grand scheme of things, not that horrible. Other large >> differences are on the order of 4, which is approximately 5% or less of >> those points. >> >> Thanks  Ariel >> >> PS for some reason, matplotlibdevel will not get your email unless you >> hit "reply all", so they have been getting my emails, but not yours. I am >> not sure whether that is what you intended, so I thought I would mention it. >> >> >> >> On Mon, Feb 8, 2010 at 1:24 AM, Ludwig Schwardt < >> ludwig.schwardt@...> wrote: >> >>> Hi, >>> >>> On Mon, Feb 8, 2010 at 5:25 AM, Ariel Rokem <arokem@...> wrote: >>> > I don't think that the cause of the discrepancy is because of the >>> > hamming/hanning window difference. I do set the window in the matlab >>> part to >>> > also be a hanning window of length nfft. >>> >>> I suspected you gave the same window to both, but I was just >>> checking... :) To find those smaller discrepancies might be a bit >>> harder then, requiring a careful comparison of the various steps >>> involved. Just for interest's sake, how big are the differences we are >>> talking about? >>> >>> Regards, >>> Ludwig >>> >> >> >> >>  >> Ariel Rokem >> Helen Wills Neuroscience Institute >> University of California, Berkeley >> http://argentum.ucbso.berkeley.edu/ariel >> > > > >  > Ariel Rokem > Helen Wills Neuroscience Institute > University of California, Berkeley > http://argentum.ucbso.berkeley.edu/ariel >  Ariel Rokem Helen Wills Neuroscience Institute University of California, Berkeley http://argentum.ucbso.berkeley.edu/ariel 