Re: [Matplotlib-users] How to plot Chebyshev polynolmials

[Fabien L. <laf...@gm...>]

No I just want to plot the third Shebitchev polynomial.

2012/1/10 Daniel Hyams <dh...@gm...>:
> I think that you're misusing Chebyshev (do you really only want to give "3"
> as a coefficient..which is just the constant function 3), and you have to
> evaluate it in order to give matplotlib some x and y data to plot.
>
> from matplotlib import pyplot as plt
> import numpy as np
>
> x = np.linspace(-1.0,1.0)
> test = np.polynomial.Chebyshev((1,2,3))
> y = test(x)
> plt.plot(x,y)
> plt.show()
>
>
>
> On Tue, Jan 10, 2012 at 9:10 AM, Fabien Lafont <laf...@gm...>
> wrote:
>>
>> I'm trying to plot Chebyshev polynolmials using:
>> numpy.polynomial.Chebyshev:
>>
>>
>> import math
>> from numpy import *
>> from numpy import polynomial as pol
>> from pylab import *
>> from scipy import *
>> from scipy import optimize
>> import warnings
>> warnings.simplefilter('ignore', np.RankWarning)
>>
>>
>> test = pol.Chebyshev(3)
>> print test
>> plot (test)
>>
>>
>> show()
>> =======================================================================
>>
>> The print return:      cheb([ 3.])
>>
>> =======================================================================
>> and plot :
>>
>>
>> Traceback (most recent call last):
>>  File "T:\Dropbox\Thèse\Python\fit sonde\test_poly_Tcheb.py", line
>> 32, in <module>
>>    plot (test)
>>  File "C:\Python27\lib\site-packages\matplotlib\pyplot.py", line 2458, in
>> plot
>>    ret = ax.plot(*args, **kwargs)
>>  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 3849, in
>> plot
>>    self.add_line(line)
>>  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 1443,
>> in add_line
>>    self._update_line_limits(line)
>>  File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 1451,
>> in _update_line_limits
>>    p = line.get_path()
>>  File "C:\Python27\lib\site-packages\matplotlib\lines.py", line 644,
>> in get_path
>>    self.recache()
>>  File "C:\Python27\lib\site-packages\matplotlib\lines.py", line 401, in
>> recache
>>    y = np.asarray(yconv, np.float_)
>>  File "C:\Python27\lib\site-packages\numpy\core\numeric.py", line
>> 235, in asarray
>>    return array(a, dtype, copy=False, order=order)
>> TypeError: float() argument must be a string or a number
>>
>>
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>
>
>
>
> --
> Daniel Hyams
> dh...@gm...
>
> ------------------------------------------------------------------------------
> Write once. Port to many.
> Get the SDK and tools to simplify cross-platform app development. Create
> new or port existing apps to sell to consumers worldwide. Explore the
> Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
> http://p.sf.net/sfu/intel-appdev
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>