Polynomial fitting with log log plot

Posted by viral parekh on Stack Overflow See other posts from Stack Overflow or by viral parekh
Published on 2012-09-27T14:20:37Z Indexed on 2012/09/29 9:37 UTC
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python

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scipy

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matplolib

I have a simple problem to fit a straight line on log-log scale. My code is,

data=loadtxt(filename)
xdata=data[:,0]
ydata=data[:,1]
polycoeffs = scipy.polyfit(xdata, ydata, 1)
yfit = scipy.polyval(polycoeffs, xdata)
pylab.plot(xdata, ydata, 'k.')
pylab.plot(xdata, yfit, 'r-')

Now I need to plot fit line on log scale so I just change x and y axis,

ax.set_yscale('log')
ax.set_xscale('log')

then its not plotting correct fit line. So how can I change fit function (in log scale) so that it can plot fit line on log-log scale?

Thanks

-Viral

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