Rank: 498 based on 136 downloads (last 30 days) and 9 files submitted
photo

Ged Ridgway

E-mail
Company/University
UCL
Lat/Long
51.523, -0.1322

Personal Profile:
Professional Interests:

 

Watch this Author's files

 

Files Posted by Ged View all
  • 1 - 5 of
  • 9
Updated   File Tags Downloads
(last 30 days) 		Comments Rating
04 Oct 2010 Group Equally Categorise data into quantiles Author: Ged Ridgway categorize, categorise, split, group, quantiles, quartiles 2 0
21 Jul 2010 DimFunc Apply a function along any dimension of an n-D array. Author: Ged Ridgway multidimensional arra..., nd, first nonsingleton di..., dim 0 1
21 Apr 2010 Unique random permutations Random sample (without replacement) from unique permutations of a vector or row-perms of a matrix Author: Ged Ridgway unique, random, permutation, combinatorics, sign flips 13 0
30 Mar 2010 Published MATLAB Files Struct array conversion Convert in either direction between struct-array and structure of arrays Author: Ged Ridgway struct, database, spreadsheet 1 0
08 Mar 2010 Published MATLAB Files Modulation tutorial Simple illustration of the Jacobian determinant as a geometric scaling factor Author: Ged Ridgway neuroimaging, morphometry, vbm, tbm, jacobian, determinant 6 0
Comments and Ratings by Ged View all
  • 1 - 5 of
  • 20
Updated File Comments Rating
15 Dec 2011 MyFisher the definitive function for the Fisher's exact and conditional test for any RxC matrix Author: Giuseppe Cardillo

Seems very useful! Might be worth (if not too much trouble) also returning the p-value from the approximate Chi-square test for comparison, since it seems that neither the Statistics toolbox nor fileexchange have this for general NxM tables.
12 Aug 2010 comparedata Compares two objects recursively. Author: Andrew Diamond

Extremely useful -- thank you!
11 Aug 2010 mmtimes: matrix chain product Return matrix chain product P = M1*M2* ... *Mn Author: Bruno Luong
11 Aug 2010 mmtimes: matrix chain product Return matrix chain product P = M1*M2* ... *Mn Author: Bruno Luong

I'm glad someone has implemented this. Two comments:

Apparently an O(N*log(N)) algorithm is available:
http://en.wikipedia.org/wiki/Matrix_chain_multiplication#An_Even_More_Efficient_Algorithm
though I don't know how this compares to the current O(N^3) one for typical values of N (e.g. the constants could make N*log(N) worse until N gets above a certain level).

More importantly (for me, anyway), I think the computation of the ordering should be a separate function, and a set ordering should then be usable in a multiplication function. E.g. if I have some code which repeatedly computes a chain multiplication in a loop, where the matrices' sizes are always the same and are known in advance, but their values vary, then much better than using mmtimes(A,B,C,...) would be to find the correct ordering first, and then hard-code that ordering in the loop. Similarly, if their sizes are constant but not known in advance, then a two-function division of labour would allow the ordering to be computed on the first iteration of the loop, and then reused without recomputation in successive iterations.
22 Jul 2010 DimFunc Apply a function along any dimension of an n-D array. Author: Ged Ridgway

See also:
http://www.mathworks.com/matlabcentral/fileexchange/16467-apply
which performs a complementary function. I have written a comment there that I hope will clarify the difference between the two.
Comments and Ratings on Ged's Files View all
  • 1 - 5 of
  • 33
Updated File Comment by Comments Rating
29 Oct 2010 Rice/Rician distribution Functions for Rice/Rician PDF: stats, samples, and distribution fitting. Author: Ged Ridgway monti guarnieri, Andrea

Very good package and great for my problem. Thanks.
I have uploaded a faster version that operates on multiple set at once. I called it "ricefit_fast", same syntax.
22 Jul 2010 DimFunc Apply a function along any dimension of an n-D array. Author: Ged Ridgway Ridgway, Ged

See also:
http://www.mathworks.com/matlabcentral/fileexchange/16467-apply
which performs a complementary function. I have written a comment there that I hope will clarify the difference between the two.
01 Jul 2010 Rice/Rician distribution Functions for Rice/Rician PDF: stats, samples, and distribution fitting. Author: Ged Ridgway Lrs, Panagiotis

Hope to find some time for the CDF . Thnx!!
27 Apr 2010 (AU)ROC(CH) Receiver Operating Characteristic curve with convex hull, plus areas under ROC and ROCCH. Author: Ged Ridgway Aleksey

nice function, thanks
27 Apr 2010 (AU)ROC(CH) Receiver Operating Characteristic curve with convex hull, plus areas under ROC and ROCCH. Author: Ged Ridgway Aleksey

ups, sorry there is a parameter to control this...
Top Tags Applied by Ged
  • 1 - 5 of
  • 66
argument processing, auc, auroc, categorise, categorize
Files Tagged by Ged View all
  • 1 - 5 of
  • 11
Updated   File Tags Downloads
(last 30 days) 		Comments Rating
04 Oct 2010 Group Equally Categorise data into quantiles Author: Ged Ridgway categorize, categorise, split, group, quantiles, quartiles 2 0
21 Jul 2010 DimFunc Apply a function along any dimension of an n-D array. Author: Ged Ridgway multidimensional arra..., nd, first nonsingleton di..., dim 0 1
21 Apr 2010 Unique random permutations Random sample (without replacement) from unique permutations of a vector or row-perms of a matrix Author: Ged Ridgway unique, random, permutation, combinatorics, sign flips 13 0
30 Mar 2010 Published MATLAB Files Struct array conversion Convert in either direction between struct-array and structure of arrays Author: Ged Ridgway struct, database, spreadsheet 1 0
09 Mar 2010 MyFisher the definitive function for the Fisher's exact and conditional test for any RxC matrix Author: Giuseppe Cardillo statistics, fishers exact conditi..., contingency table, twoway, rxc, nxm 12 3
  • 5.0
5.0 | 1 rating

Contact us at files@mathworks.com