Locate elements of a vector inside a meshgrid
3 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
I'm trying to build a matrix RES, with the same dimensions of X and Y, that has a '1' in the position pointed (with a tollerance tollX and tollY) by the i-th couple contained in V.
[X,Y]=meshgrid(0:1:3,-2:1:2);
V=[2.1 1.2;
0.2 0.7;
3.1 1.9;
1.6 -1];
tollX=0.5;
tollY=0.5;
RES=0;
for i=1:length(V)
RES=(V(i,1)<X+tollX).*(V(i,1)>X-tollX).*(V(i,2)<Y+tollY).*(V(i,2)>Y-tollY)+RES;
end
This "rough" solution works well with small meshgrids and V, but since i have to manage far bigger data sets i would like to vectorize and refine the code to get better performances.
P.S. I expected '&' operator to be faster in general than ' .* ', but this doesn't seem to be true, at least for my case.
To test this I simply changed the statement inside the for loop with this one:
RES=((V(i,1)<X+tollX)&(V(i,1)>X-tollX)&(V(i,2)<Y+tollY)&(V(i,2)>Y-tollY))|RES;
0 Kommentare
Antworten (1)
Rik
am 6 Okt. 2020
I would suggest using ismembertol, or consider functions like normxcorr2 from the image processing toolbox.
3 Kommentare
Rik
am 6 Okt. 2020
I'm not quite sure how implicit expansion (with bsxfun) would increase performance. I suspect ismembertol would be more efficient. I also don't necessarily see how find would be useful.
Siehe auch
Kategorien
Mehr zu Resizing and Reshaping Matrices finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!