Re: Plotting histograms
Thanks Robert, My previous problem is solved(I was using 'from matplotlib.pylab import *') but now I am facing another problem. I want to plot the histogram of eigenvalues calculated and I am using the following code: ___ import numpy from matplotlib import pylab n=100 ra = numpy.random la = numpy.linalg A = ra.standard_normal((n,n)) S = (A + numpy.transpose(A))/(2*n^(1/2)) eig = la.eigvals(S) [N,x]=pylab.hist(eig, 10) # make a histogram - But again it is giving some error, which is given below: File C:\Documents and Settings\amitsoni\Desktop\New Folder\wignerpython, line 15, in module [N,x]=pylab.hist(eig, 10) # make a histogram ValueError: too many values to unpack Can anyone help me out with this?? Thanks Amit Robert Kern wrote: [EMAIL PROTECTED] wrote: hi, I have some values(say from -a to a) stored in a vector and I want to plot a histogram for those values. How can I get it done in python. I have installed and imported the Matplotlib package but on executing the code [N,x]=hist(eig, 10) # make a histogram I am getting an error saying NameError: name 'hist' is not defined. I presume what you did was something like this: from matplotlib import pylab [N,x] = hist(eig, 10) What you actually want is this: from matplotlib import pylab [N,x] = pylab.hist(eig, 10) Or, if you're at the interactive prompt (but remember that it is inadvisable to do so in modules): from matplotlib.pylab import * [N,x] = hist(eig, 10) You will probably want to review the section of the tutorial on importing modules if you don't understand the differences. -- Robert Kern I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Plotting histograms
[EMAIL PROTECTED] wrote: Thanks Robert, My previous problem is solved(I was using 'from matplotlib.pylab import *') but now I am facing another problem. I want to plot the histogram of eigenvalues calculated and I am using the following code: ___ import numpy from matplotlib import pylab n=100 ra = numpy.random la = numpy.linalg A = ra.standard_normal((n,n)) S = (A + numpy.transpose(A))/(2*n^(1/2)) Note that this line won't do what you think it does. First, one integer divided by another integer returns an integer, so (1/2) == 0. Also, ^ is not exponentiation but bitwise XOR. Use ** for exponentiation. However, in this case, you should use numpy.sqrt(). eig = la.eigvals(S) [N,x]=pylab.hist(eig, 10) # make a histogram - But again it is giving some error, which is given below: File C:\Documents and Settings\amitsoni\Desktop\New Folder\wignerpython, line 15, in module [N,x]=pylab.hist(eig, 10) # make a histogram ValueError: too many values to unpack Can anyone help me out with this?? pylab.hist() does not return two values, it returns three. Sorry I didn't catch that earlier. -- Robert Kern I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Plotting histograms
[EMAIL PROTECTED] wrote: hi, I have some values(say from -a to a) stored in a vector and I want to plot a histogram for those values. How can I get it done in python. I have installed and imported the Matplotlib package but on executing the code [N,x]=hist(eig, 10) # make a histogram I am getting an error saying NameError: name 'hist' is not defined. Is there any other way to plot histograms over a given range? # create random vector ... from random import randrange a = 5 v = [randrange(-a, a+1) for i in xrange(100)] # print histogram ... for i in range(-a, a+1): ... print %+d %s % (i, '*' * v.count(i)) ... -5 * -4 * -3 * -2 ** -1 ** +0 * +1 +2 *** +3 * +4 +5 :) -- Roberto Bonvallet -- http://mail.python.org/mailman/listinfo/python-list
Re: Plotting histograms
Thanks for the replies ... its perfect now ... but just one more thing ... how can I plot another function(a semi circle) in the same histogram? thanks amit Robert Kern wrote: [EMAIL PROTECTED] wrote: Thanks Robert, My previous problem is solved(I was using 'from matplotlib.pylab import *') but now I am facing another problem. I want to plot the histogram of eigenvalues calculated and I am using the following code: ___ import numpy from matplotlib import pylab n=100 ra = numpy.random la = numpy.linalg A = ra.standard_normal((n,n)) S = (A + numpy.transpose(A))/(2*n^(1/2)) Note that this line won't do what you think it does. First, one integer divided by another integer returns an integer, so (1/2) == 0. Also, ^ is not exponentiation but bitwise XOR. Use ** for exponentiation. However, in this case, you should use numpy.sqrt(). eig = la.eigvals(S) [N,x]=pylab.hist(eig, 10) # make a histogram - But again it is giving some error, which is given below: File C:\Documents and Settings\amitsoni\Desktop\New Folder\wignerpython, line 15, in module [N,x]=pylab.hist(eig, 10) # make a histogram ValueError: too many values to unpack Can anyone help me out with this?? pylab.hist() does not return two values, it returns three. Sorry I didn't catch that earlier. -- Robert Kern I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Ec -- http://mail.python.org/mailman/listinfo/python-list
Re: Plotting histograms
[EMAIL PROTECTED] wrote: Thanks for the replies ... its perfect now ... but just one more thing ... how can I plot another function(a semi circle) in the same histogram? Just call the appropriate plotting function after you plot the histogram. By default, the second plot will go into the same figure as the first. Something like the following should suffice: x = numpy.linspace(-1.0, 1.0, 201) y = numpy.sqrt(1.0 - x*x) pylab.plot(x, y, 'k-') Look at the matplotlib documentation for more information. You will probably also want to ask future questions on the matplotlib-users mailing list instead of here. -- Robert Kern I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
pylab package dependencies (was: Plotting histograms)
In article [EMAIL PROTECTED], Robert Kern [EMAIL PROTECTED] wrote: I presume what you did was something like this: from matplotlib import pylab [N,x] = hist(eig, 10) What you actually want is this: from matplotlib import pylab [N,x] = pylab.hist(eig, 10) Or, if you're at the interactive prompt (but remember that it is inadvisable to do so in modules): from matplotlib.pylab import * [N,x] = hist(eig, 10) You will probably want to review the section of the tutorial on importing modules if you don't understand the differences. Is pylab part of matplotlib? I always thought it was the other way around. I have a similar view of numpy as part of scipy. Maybe I'm confused on the dependencies. I find it confusing in the examples sometimes when the bigger package is imported (e.g. scipy) and then a subpackage is also imported. Like this: from scipi import * from scipi import numpy I know I've seen stuff like that, but I don't get it. The dependencies are confusing to me. I did a search of the tutorial on 'import' but didn't find the answer. -- Lou Pecora (my views are my own) REMOVE THIS to email me. -- http://mail.python.org/mailman/listinfo/python-list
Plotting histograms
hi, I have some values(say from -a to a) stored in a vector and I want to plot a histogram for those values. How can I get it done in python. I have installed and imported the Matplotlib package but on executing the code [N,x]=hist(eig, 10) # make a histogram I am getting an error saying NameError: name 'hist' is not defined. Is there any other way to plot histograms over a given range? thanks Amit -- http://mail.python.org/mailman/listinfo/python-list
Re: Plotting histograms
[EMAIL PROTECTED] wrote: hi, I have some values(say from -a to a) stored in a vector and I want to plot a histogram for those values. How can I get it done in python. I have installed and imported the Matplotlib package but on executing the code [N,x]=hist(eig, 10) # make a histogram I am getting an error saying NameError: name 'hist' is not defined. I presume what you did was something like this: from matplotlib import pylab [N,x] = hist(eig, 10) What you actually want is this: from matplotlib import pylab [N,x] = pylab.hist(eig, 10) Or, if you're at the interactive prompt (but remember that it is inadvisable to do so in modules): from matplotlib.pylab import * [N,x] = hist(eig, 10) You will probably want to review the section of the tutorial on importing modules if you don't understand the differences. -- Robert Kern I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth. -- Umberto Eco -- http://mail.python.org/mailman/listinfo/python-list
Re: Plotting histograms
On 16 Oct 2006 20:49:10 -0700, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: hi, I have some values(say from -a to a) stored in a vector and I want to plot a histogram for those values. How can I get it done in python. I have installed and imported the Matplotlib package but on executing the code [N,x]=hist(eig, 10) # make a histogram I am getting an error saying NameError: name 'hist' is not defined. Use the statement 'from pylab import *' in the beginning of your program. Others, of course, may find it more tasteful and Pythonic to do: [N,x]=pylab.hist(eig, 10) i.e., prefix it with the package name. Wouldn't want to clutter the global namespace of your program after all. Good luck with it then. I think I see a reference to advanced linear algebra with 'eig' (Eigen-?) and I'm sure you understand that better than I. :) -- Theerasak -- http://mail.python.org/mailman/listinfo/python-list
