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##----------------------------------------------------------------------------
## Name: psd_scale.py
## 
## Purpose: Test Power Spectral Density of 1Vrms data
## Depends on Python SciPy and NumPy
## 
## Author: J Park
##
## Created: 10/17/07
##
## Modified: 
##----------------------------------------------------------------------------
try:
 from numpy import * # www.numpy.org numpy.scipy.org
except ImportError: 
 print "Failed to import numpy."
 
try:
 import pylab as mp # matplotlib.sourceforge.net
 from matplotlib.font_manager import fontManager, FontProperties 
except ImportError: 
 print "Failed to import pylab."
 
# Default Parameters
nFFT = 1024 
overlap = 512 
freqSample = 100. 
PlotAll = False
WriteOutput = False
##----------------------------------------------------------------------------
## Main module
def main():
 deltaF = freqSample/nFFT # Frequency resolution in Hz
 deltaT = 1./freqSample # Sample interval
 print 'Sample interval %e (s)' % (deltaT)
 print 'Frequency resolution %e (Hz)' % (deltaF)
 # Setup Plots
 # ----------------------------------------------------------------------
 mp.figure(1)
 mp.title ( "PSD" )
 mp.ylabel( "(dB)" )
 mp.xlabel( "Frequency (Hz)" )
 legendFont = FontProperties(size='small')
 ymin = 0
 ymax = 30
 xmin = 0
 xmax = 50
 xticks = 5
 yticks = 5
 if PlotAll:
 mp.figure(2)
 mp.title ( "Input Timeseries" )
 mp.ylabel( "Amplitude" )
 mp.xlabel( "time (s)" )
 # Create some synthetic data with unity RMS amplitude = 0 dB
 # ----------------------------------------------------------------------
 t = mp.arange(0., 60., deltaT) # 60 seconds at deltaT interval
 A = 1.414
 
 y0 = A * sin( 2. * math.pi * 5 * t )
 y1 = A * sin( 2. * math.pi * 10 * t )
 y2 = A * sin( 2. * math.pi * 20 * t )
 y3 = A * sin( 2. * math.pi * 30 * t )
 y4 = A * sin( 2. * math.pi * 40 * t )
 y5 = A * sin( 2. * math.pi * 45 * t )
 dataList = [ y0, y1, y2, y3, y4, y5 ]
 
 for data in dataList:
 inputDataLen = len( data )
 numAverages = math.floor( inputDataLen / (overlap) ) - 1
 normalizedRandomError = 1./math.sqrt( numAverages )
 print "%d points" % ( inputDataLen ),
 print "%d averages" % (numAverages),
 print "normalized random error %.3f" % ( normalizedRandomError )
 mp.figure(1)
 (Pxx, freqs) = mp.psd( data,
 NFFT = nFFT,
 Fs = freqSample,
 noverlap = overlap,
 lw = 2,
 label = '' )
 Pxx_dB = 10.*log10(Pxx)
 
 if PlotAll:
 mp.figure(2)
 mp.plot(t, data, label='' )
 # Write Output data
 # ----------------------------------------------------------------------
 if WriteOutput:
 PxxLen = len(Pxx)
 OutputFile = "PSD.dat"
 fdOutFile = open( OutputFile, 'a' )
 fdOutFile.write( "Freq\t\tPower(dB)\n" )
 for i in range(PxxLen):
 fdOutFile.write( "%.4e\t%.3f\n" % ( freqs[i], Pxx_dB[i] ) )
 fdOutFile.close()
 print "Wrote ", PxxLen, " points to ", OutputFile
 
 # Show the Plot
 # ----------------------------------------------------------------------
 mp.figure(1)
 mp.axis([xmin, xmax, ymin, ymax])
 mp.xticks( arange(xmin, xmax+1, xticks) )
 mp.yticks( arange(ymin, ymax , yticks) )
 mp.title('')
 mp.xlabel('Frequency (Hz)')
 mp.ylabel(r'$\tt{dB re V^2/Hz}$')
 #mp.legend( loc='upper right', prop=legendFont )
 if WriteOutput:
 plotFileName = "PSD.png"
 mp.savefig( plotFileName )
 print "Wrote png image to ", plotFileName
 if PlotAll:
 mp.figure(2)
 #mp.legend( loc='lower left', prop=legendFont )
 mp.show()
 print "Normal Exit"
## Main module
##----------------------------------------------------------------------------
##----------------------------------------------------------------------------
## Provide for cmd line invocation
if __name__ == "__main__":
 main()

Yep that can be a good idea. I don't know anything on how mathtext is worki=
ng=20
but I'm not completely sure that the problem is with freetype because=20
sometime that can work. In reality every character I tested worked but you=
=20
have to put in a certain order. To understand a little bit more what I try =
to=20
say (very badly) see the script join and the figure.=20
=20
I hope that can help a little bit to try to find the reason of this behavio=
ur.
N
Le Thursday 25 October 2007 15:41:40 Michael Droettboom, vous avez =C3=A9cr=
it=C2=A0:
> Darren Dale wrote:
> > Hi Mike,
> >
> > On Tuesday 23 October 2007 09:05:56 am Michael Droettboom wrote:
> >> Unfortunately, I can't reproduce this on my machine even with the late=
st
> >> stable version of freetype-2.5.3 (which is the same version in Ubuntu
> >> Gutsy).
> >
> > I think you mean freetype-2.3.5. I also have that version installed,
> > although the mpl setup script is reporting 9.16.3.
>
> Yes. freetype-2.3.5. There are arcane historical reasons I don't fully
> comprehend why the pkgconfig version doesn't match the release version
> (and why freetype2 is called freetype6 on Debian and derivatives)...
> but my numbers do match yours.
>
> >> The Ubuntu/Debian package of freetype has a lot of patches
> >> applied, and I don't know if they are causing this (but from the looks
> >> of them, I doubt it).
> >>
> >> Can you set debug.verbose to "annoying" and send me the output of your
> >> matplotlib run? I want to rule out any font-loading problems.
> >
> > It's attached. I'm running 64bit gentoo, everything compiled with
> > gcc-4.2.2, in case its relevent.
>
> Always good to have more details, but I'm sort of at a loss on this one,
> especially since I can't reproduce it.
>
> Maybe we need to take a poll on this list of who is working and who
> isn't to see what the source of the breakage may be...
>
> Cheers,
> Mike

Darren Dale wrote:
> Hi Mike,
> 
> On Tuesday 23 October 2007 09:05:56 am Michael Droettboom wrote:
>> Unfortunately, I can't reproduce this on my machine even with the latest
>> stable version of freetype-2.5.3 (which is the same version in Ubuntu
>> Gutsy).
> 
> I think you mean freetype-2.3.5. I also have that version installed, although 
> the mpl setup script is reporting 9.16.3.
Yes. freetype-2.3.5. There are arcane historical reasons I don't fully 
comprehend why the pkgconfig version doesn't match the release version 
(and why freetype2 is called freetype6 on Debian and derivatives)... 
but my numbers do match yours.
>> The Ubuntu/Debian package of freetype has a lot of patches 
>> applied, and I don't know if they are causing this (but from the looks
>> of them, I doubt it).
>>
>> Can you set debug.verbose to "annoying" and send me the output of your
>> matplotlib run? I want to rule out any font-loading problems.
> 
> It's attached. I'm running 64bit gentoo, everything compiled with gcc-4.2.2, 
> in case its relevent.
Always good to have more details, but I'm sort of at a loss on this one, 
especially since I can't reproduce it.
Maybe we need to take a poll on this list of who is working and who 
isn't to see what the source of the breakage may be...
Cheers,
Mike
>> Michael Droettboom wrote:
>>> I can't reproduce this bug on my own machine with SVN head. I suspect
>>> this is freetype2 related -- that's the library that actually performs
>>> the rendering of the characters for the Agg backend. The fact the
>>> humufr saw this after upgrading to Gutsy suggests there might have been
>>> change to freetype that is now revealing possibly an incorrect usage
>>> in matplotlib. Can you please send the version of freetype you are
>>> using? (pkg-config --modversion freetype2)
>>>
>>> My machine has the (fairly old) 2.1.9.
>>>
>>> I'm going to try installing the latest freetype and see if I can
>>> reproduce this bug.
>>>
>>> [I believe this is an instance of the same bug that Darren sent me
>>> off-list.]
>>>
>>> Cheers,
>>> Mike
>>>
>>> hu...@ya... wrote:
>>>> Sorry I didn't know the difference...
>>>>
>>>> N.
>>>>
>>>> Le Friday 19 October 2007 10:52:25 Darren Dale, vous avez écrit :
>>>>> On Friday 19 October 2007 10:38:36 am hu...@ya... wrote:
>>>>>> Le Friday 19 October 2007 08:37:00 Darren Dale, vous avez écrit :
>>>>>>> On Thursday 18 October 2007 11:49:50 am hu...@ya... wrote:
>>>>>>>> 	Hi,
>>>>>>>>
>>>>>>>> I have a small problem with label.
>>>>>>>>
>>>>>>>>
>>>>>>>> plot([0,1],[0,1])
>>>>>>>> xlabel(r'$ABCDEF$',fontsize=35)
>>>>>>>>
>>>>>>>> (but the size doesn't change anything) I obtain the result visible
>>>>>>>> on the figure join. I think there are a problem when using latex and
>>>>>>>> how the first character is handle.
>>>>>>> I don't think its a problem with matplotlib; I can't reproduce the
>>>>>>> problem on my machine. Maybe its an issue with your dvipng? I'm using
>>>>>>> version 1.9.
>>>>>> Oups I found the problem, I don't know why because it was working fine
>>>>>> before the upgrade to gutsy but I have to change matplotlib
>>>>>> configuration and everything is working fine if I put in the file:
>>>>>>
>>>>>> rc('text', usetex=True)
>>>>> In your first email you said you were using latex, but you were
>>>>> actually using mathtext. I can confirm the problem when I disable
>>>>> usetex and instead use mathtext. Mike, is this something easy to fix?
>>>>>
>>>>> Darren
>>>> ------------------------------------------------------------------------
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> 
> 
> 
-- 
Michael Droettboom
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Hello folks,
I have a Gaussian peak centered on zero. When the plot is drawn on
screen with the GTKAgg backend, the peak is shown in the correct place.
 When I either click on the disk icon and save the plot as eps or use
savefig, the peak is shifted to the left of zero by several x axis units.
I am using Python 2.5 with matplotlib 0.90.1 and numpy 1.0.3. and scipy
0.5.1 in my script. These are running on my Fedora 7 box. I compiled
and installed mpl 0.90.1 this morning because I noticed this behavior
with python-matplotlib-0.90.0 that I had installed with yum. I also see
this behavior if I run my script from the command line and from ipython
0.8.1.
When I save using PNG, the peak is in the correct place. My Mac also
saves both EPS and PNG correctly.
Any thoughts?
Dave
- --
David D. Clark
Electrical Engineer
P-23, Neutron Science and Technology
e-mail mailto:dd...@la...
GPG Public key 0x018D6523 available at http://pgp.mit.edu
http://www.gnupg.org has information about public key cryptography
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (GNU/Linux)
Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org
iD8DBQFHIOunNu7GcwGNZSMRAlKnAJ46KFuJVNN0rC6EHgredtUHYZyvdQCgqQNG
OiwS8VN/qZ1ula37vDP7Q88=
=/1De
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A simple solution would be:
numbers, text = yticks()
mytext = ['%.2f' % n for n in numbers]
yticks(numbers, mytext)
If you need fancier formatting look at Ticker and Formatter API
http://matplotlib.sourceforge.net/matplotlib.ticker.html
For sure there's something about this in the examples as well.
Best! Bernhard
On 10/23/07, pyt...@ma... <pyt...@ma...> wrote:
>
> Hi guys.
> I'm just a newbie at matplotlib. I couldn't find the answer on my
> quistion in project's docs.
> I've wrote the following code:
> from pylab import *
> semilogy([1, 5, 2, 3, 1, 6], basey=2)
> show()
>
>
> It works OK but I'd like to see usual decimal numbers instead of 2^0,
> 2^1, 2^2 ... on y axis.
> How can I do that?
> Thnx.
>
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> _______________________________________________
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