On 2014/12/17, 5:37 AM, Thomas Caswell wrote: > What version of mpl are you using? These functions got a lot of work > between 1.3 and 1.4.
Tom, Sorry, I answered only in his parallel github issue. https://github.com/matplotlib/matplotlib/issues/3927. I'm closing it now. The upshot is that psd returns the power but plots it in db. Eric > > I also suspects that there is a normalization issue going on with power > vs power density. > > Tom > > On Tue, Dec 16, 2014, 22:28 xkryptor <xkryp...@gmail.com > <mailto:xkryp...@gmail.com>> wrote: > > Hi all, > > I tried calculating the power spectral density using matplotlib > mlab function psd (). I plotted using two methods: > > 1. At first I plot it directly using plt.psd (red line in plot) > 2. Then I output the values from psd() to variables and plotting the > variables (blue line in plot) > > The code I used: > > power, freqs = plt.psd(P * 100000, len(P), Fs = 1 / dt, scale_by_freq=0) > plt.psd(P * 100000, len(P), 1 / dt, scale_by_freq=0) > plt.plot(freqs, power) > > But the plots are different, I expected it to be coincident. From > where does the discrepancy arise? > > Inline image 1 > > ------------------------------__------------------------------__------------------ > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > with Interactivity, Sharing, Native Excel Exports, App Integration & > more > Get technology previously reserved for billion-dollar corporations, FREE > > http://pubads.g.doubleclick.__net/gampad/clk?id=164703151&__iu=/4140/ostg.clktrk > > <http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk>_________________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.__sourceforge.net > <mailto:Matplotlib-users@lists.sourceforge.net> > https://lists.sourceforge.net/__lists/listinfo/matplotlib-__users > <https://lists.sourceforge.net/lists/listinfo/matplotlib-users> > > > > ------------------------------------------------------------------------------ > Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server > from Actuate! Instantly Supercharge Your Business Reports and Dashboards > with Interactivity, Sharing, Native Excel Exports, App Integration & more > Get technology previously reserved for billion-dollar corporations, FREE > http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk > > > > _______________________________________________ > Matplotlib-users mailing list > Matplotlib-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-users > ------------------------------------------------------------------------------ Download BIRT iHub F-Type - The Free Enterprise-Grade BIRT Server from Actuate! Instantly Supercharge Your Business Reports and Dashboards with Interactivity, Sharing, Native Excel Exports, App Integration & more Get technology previously reserved for billion-dollar corporations, FREE http://pubads.g.doubleclick.net/gampad/clk?id=164703151&iu=/4140/ostg.clktrk _______________________________________________ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
