matplotlib-users

[Matplotlib-users] How to plot Chebyshev polynolmials

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

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

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

[Daniel H. <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
>
>
> ------------------------------------------------------------------------------
> 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
>



-- 
Daniel Hyams
dh...@gm...

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
>>
>>
>> ------------------------------------------------------------------------------
>> 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
>
>
>
>
> --
> 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
>

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

[Daniel H. <dh...@gm...>]

Regardless of exactly which polynomial you are after, I've showed you how
to plot a cheb. poly.  Can you not work with the code given and plot the
exact variation of polynomial you want?



On Tue, Jan 10, 2012 at 9:46 AM, Fabien Lafont <laf...@gm...>wrote:

> 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
> >>
> >>
> >>
> ------------------------------------------------------------------------------
> >> 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
> >
> >
> >
> >
> > --
> > 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
> >
>



-- 
Daniel Hyams
dh...@gm...

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

[<jos...@gm...>]

I'm not used to reply-all


---------- Forwarded message ----------
From:  <jos...@gm...>
Date: Tue, Jan 10, 2012 at 10:20 AM
Subject: Re: [Matplotlib-users] How to plot Chebyshev polynolmials
To: Fabien Lafont <laf...@gm...>


On Tue, Jan 10, 2012 at 9:46 AM, Fabien Lafont <laf...@gm...> wrote:
> No I just want to plot the third Shebitchev polynomial.

the vander functions give you the basis functions for a given x, or
use coefficients only for the polynomial you want, if I understand
correctly what you want

>>> import numpy as np
>>> from numpy import polynomial as poly
>>> chebs = [poly.Chebyshev(coef) for coef in np.eye(5)]
>>> for p in chebs: plt.plot(x, p(x))
...
[<matplotlib.lines.Line2D object at 0x046D91F0>]
[<matplotlib.lines.Line2D object at 0x046D9510>]
[<matplotlib.lines.Line2D object at 0x046D9830>]
[<matplotlib.lines.Line2D object at 0x046D9B50>]
[<matplotlib.lines.Line2D object at 0x046D9E70>]
>>> plt.show()

or
>>> plt.plot(poly.chebvander(x, 5))

Josef



>
> 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
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> 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
>>
>>
>>
>>
>> --
>> 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
>>
>
> ------------------------------------------------------------------------------
> 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