Histogram for pairs of values
in [Matlab]
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From: Jim O'Doherty on 21 Jul 2010 12:26 Hi matlab-ers, I've got an array of X and an array of Y position data. Can anyone tell me how I might determine how often each pair of X,Y values occur? I was thinking along the lines of the hist() command but over 2 arrays but hit a wall. Thanks, Jim
From: Bruno Luong on 21 Jul 2010 12:37 "Jim O'Doherty" <jim.odoherty(a)gmail.com> wrote in message <i2772s$2da$1(a)fred.mathworks.com>... > Hi matlab-ers, > I've got an array of X and an array of Y position data. > Can anyone tell me how I might determine how often each pair of X,Y values occur? I was thinking along the lines of the hist() command but over 2 arrays but hit a wall. > Thanks, > Jim This FEX submission might be of your interest: http://www.mathworks.com/matlabcentral/fileexchange/23897-n-dimensional-histogram Bruno
From: Walter Roberson on 21 Jul 2010 12:48 Jim O'Doherty wrote: > I've got an array of X and an array of Y position data. Can anyone tell > me how I might determine how often each pair of X,Y values occur? I was > thinking along the lines of the hist() command but over 2 arrays but hit > a wall. As I recall the Matlab File Exchange has several multi-dimensional histogram routines. I think I've even posted roughed out code for one myself earlier this year, but the ones in FEX have been tested.
From: Jim O'Doherty on 21 Jul 2010 16:29 Thanks for the point in the right direction Bruno. Does my data need to be sorted? My X, Y arrays are electron positions so they are not in any increasing/decreasing order. I seem to be getting an error saying it requires monotonically decreasing arrays Thanks, Jim "Bruno Luong" <b.luong(a)fogale.findmycountry> wrote in message <i277ng$dhv$1(a)fred.mathworks.com>... > "Jim O'Doherty" <jim.odoherty(a)gmail.com> wrote in message <i2772s$2da$1(a)fred.mathworks.com>... > > Hi matlab-ers, > > I've got an array of X and an array of Y position data. > > Can anyone tell me how I might determine how often each pair of X,Y values occur? I was thinking along the lines of the hist() command but over 2 arrays but hit a wall. > > Thanks, > > Jim > > This FEX submission might be of your interest: > http://www.mathworks.com/matlabcentral/fileexchange/23897-n-dimensional-histogram > > Bruno
From: Bruno Luong on 21 Jul 2010 16:48
"Jim O'Doherty" <jim.odoherty(a)gmail.com> wrote in message <i27lak$l0q$1(a)fred.mathworks.com>... > Thanks for the point in the right direction Bruno. Does my data need to be sorted? My X, Y arrays are electron positions so they are not in any increasing/decreasing order. I seem to be getting an error saying it requires monotonically decreasing arrays > Thanks, > Jim Assuming you deal only with single but unsorted X, how did you intend to use HISTC to count? Probably you have to build a sorted edge from X, e.g. with UNIQUE. The same approach works with (X,Y). Bruno |