Rank: 1314 based on 109 downloads (last 30 days) and 3 files submitted
photo

James Conder

E-mail
Company/University
Southern Illinois University
Lat/Long
37.715, -89.2175

Personal Profile:
Professional Interests:

 

Watch this Author's files

 

Files Posted by James View all
Updated   File Tags Downloads
(last 30 days)
Comments Rating
14 Feb 2014 Screenshot Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder logistic, curvefitting 50 6
23 Aug 2013 Screenshot Gaussian smoothing filter Function to smooth a time series using a Gaussian filter. Author: James Conder gaussian filter, signal processing, smoothing 43 0
16 May 2013 F-Test Test whether addition of model parameters is warranted by improvement of data misfits. Author: James Conder statistics, ftest 16 0
  • 5.0
5.0 | 1 rating
Comments and Ratings by James View all
Updated File Comments Rating
12 Feb 2014 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder

Andrew, I spent some time looking at it, and think I have fixed the problem. I just uploaded a newer version. Once it is up, please try your dataset on it and let me know how it goes.

28 May 2013 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder

Hi Darren,

Sorry about the plotting calls. I realized that I forgot to remove them just after resubmitting. I guess the follow up submission with those removed is still moving though the system.

Good catch on reversing t. It is one of those bugs introduced when addressing a different problem. I'll fix that bug and put a test example in the help comments in new submission later today.

23 May 2013 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder

Thanks for the feedback, Darren. I've made a fix based on your idea of rescaling the vector internally, and submitted an update. It isn't completely obvious to me why Qpre goes to the mean of Q for some scalings of t. In any case, I hope my fix is general and not limited to your special case. Keep me posted.

16 May 2013 Fit Logistic Curve to a Data Set This is a Matlab GUI, that will try to fit a logistic function to a given set of data. Author: Varuna De Silva

I suspect the problem Rita and Michael were having is that their data describes a decreasing logistic and the program is set up to do an increasing logistic. I just uploaded a non-GUI fit_logistic function and at first it failed with Rita's data, too. Fortunately, it is an easy fix by making the time series negative.

Comments and Ratings on James' Files View all
Updated File Comment by Comments Rating
12 Feb 2014 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder Conder, James

Andrew, I spent some time looking at it, and think I have fixed the problem. I just uploaded a newer version. Once it is up, please try your dataset on it and let me know how it goes.

10 Feb 2014 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder Andrew

James,

Great function, thank you. I too have the issue with outputting a constant value for Qpre, and, as with Darren, changing the scaling of the value for t fixes this. My t values scale between 0 and 1 in steps of 0.001.

Many thanks

28 May 2013 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder Conder, James

Hi Darren,

Sorry about the plotting calls. I realized that I forgot to remove them just after resubmitting. I guess the follow up submission with those removed is still moving though the system.

Good catch on reversing t. It is one of those bugs introduced when addressing a different problem. I'll fix that bug and put a test example in the help comments in new submission later today.

27 May 2013 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder Rowland, Darren

Hey James,

I've tested out the new code and it works a lot better for my case. One problem I've now identified is that you are not re-reversing t at the end of the function, so the calculated Qpre can be in error.

Other than this, I would suggest for you to include a brief usage example within the Help comments, e.g. constructing data from known parameters, adding some random error and obtaining parameter estimates. Just a few lines to help someone getting started.

Also, you should turn the various plotting calls off by default then have an extra (optional) input parameter for people to use to turn them on.

Hope that helps,
Darren

23 May 2013 Logistic curve fit Fit a time series to a best-fitting logistic function. Author: James Conder Conder, James

Thanks for the feedback, Darren. I've made a fix based on your idea of rescaling the vector internally, and submitted an update. It isn't completely obvious to me why Qpre goes to the mean of Q for some scalings of t. In any case, I hope my fix is general and not limited to your special case. Keep me posted.

Contact us