Re: [Matplotlib-users] Sigmoid Curve Fitting
Hi, Scipy.optimize.leastsq finds a least square fit to an arbitrary function. Check the scipy cookbook example: http://www.scipy.org/Cookbook/FittingData Regards, Bartosz On 20.09.2010, at 22:36, Chris Spencer wrote: Hi, Does Matplotlib/Numpy/Scipy contain the ability to fit a sigmoid curve to a set of data points? Regards, Chris -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users Bartosz Telenczuk Institute for Theoretical Biology Humboldt University of Berlin Germany http://neuroscience.telenczuk.pl -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Sigmoid Curve Fitting
Chris Spencer chriss...@... writes: I had already encountered zunzun.com while Googling the problem. I'm not sure what to make of it, although it seems to be an online curve-fitting service. Unfortunately, my usage requires the ability to run the process locally. The fitting source code for http://zunzun.com is freely available under a BSD-style license on Google's source code repository at http://code.google.com/p/pythonequations/downloads/list and comes with many examples - so you *can* run it locally. James Phillips zun...@zunzun.com http://zunzun.com -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
[Matplotlib-users] Sigmoid Curve Fitting
Hi, Does Matplotlib/Numpy/Scipy contain the ability to fit a sigmoid curve to a set of data points? Regards, Chris -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Sigmoid Curve Fitting
On Mon, Sep 20, 2010 at 3:36 PM, Chris Spencer chriss...@gmail.com wrote: Hi, Does Matplotlib/Numpy/Scipy contain the ability to fit a sigmoid curve to a set of data points? Regards, Chris I am very curious to know how this is done. I have seen in many Cloud Condensation Nuclei (CCN) counter calibration experiments [e.g. Rose et. al. (2008) - p1156, fig2 http://www.atmos-chem-phys.net/8/1153/2008/acp-8-1153-2008.html] people use sigmoidal fits. Never seen a code is shared so far or how it is obtained. from scipy.optimize import leastsq could be a good point to start. To me this fit is very likely a least square minimization problem. You have your tanh(x) or 1/(1+e^-x) as a sigmoidal function, and you should find the points that will make the error minimal for a given discrete points/measurements. from scipy.optimize import curve_fit might be another way to approach. -- Gökhan -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
Re: [Matplotlib-users] Sigmoid Curve Fitting
Thank you. I'll try investigating Scipy further. I've already tried applying some least-squares code for Numpy (http://pingswept.org/2009/01/24/least-squares-polynomial-fitting-in-python/) to my sigmoid data, but it only seems to fit parabolas. I had already encountered zunzun.com while Googling the problem. I'm not sure what to make of it, although it seems to be an online curve-fitting service. Unfortunately, my usage requires the ability to run the process locally. Regards, Chris On Mon, Sep 20, 2010 at 6:35 PM, Gökhan Sever gokhanse...@gmail.com wrote: On Mon, Sep 20, 2010 at 3:36 PM, Chris Spencer chriss...@gmail.com wrote: Hi, Does Matplotlib/Numpy/Scipy contain the ability to fit a sigmoid curve to a set of data points? You could also experiment at zunzun.com. Choose 2D sigmoidal from the 2D function scroll list. -- Gökhan -- Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev ___ Matplotlib-users mailing list Matplotlib-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-users
