Speed up comparing two arrays and write into new array
2 vues (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Daniel Rohrer
le 19 Oct 2021
Modifié(e) : Daniel Rohrer
le 19 Oct 2021
Hello,
I compare values of two arrays, and write the values of an associated array into a new one. Unfortunately, this comparison is quite slow. I know vectorization is a way to do it, but I don't know how in this case. Below are smaller arrays for testing, it can go up to 1'000'000 x T or so. Looking at the profiler data, the comparison takes 99% of the time for below code snippet with large arrays.
I got three initial arrays:
coordIndex: 514x4 double (integer), with most values occurring several times. Same values as in Vert_ID_mat, so 218 different values. Array can contain NaN-Values
Vert_ID_mat: 218x1 double (integer), every value only once
Colors_Res: 514x4 cell (strings). Can contain zeros, which are associated to the NaN-values
Resulting array:
Assoc_Colors: 218x1 cell (strings)
I use following code right now:
for k = 1:size(coordIndex,1)
for kk = 1:size(coordIndex,2)
for i = 1:size(Vert_ID_mat,1)
if coordIndex(k,kk) == Vert_ID_mat(i) %isequal
Assoc_Colors{i} = Colors_Res(k, kk);
end
end
end
end
Assoc_Colors = Assoc_Colors.';
How can I write a faster code and achieve a faster processing time?
Best regards
Daniel
0 commentaires
Réponse acceptée
Bruno Luong
le 19 Oct 2021
Modifié(e) : Bruno Luong
le 19 Oct 2021
For simplification I use numerical data for Colors_Res/Assoc_Colors adatp tou your data type
clear
% Dummy test data
coordIndex=randi(9,8,9);
Colors_Res=rand(size(coordIndex));
Vert_ID_mat=randi(9,10,1);
% Your method
for k = 1:size(coordIndex,1)
for kk = 1:size(coordIndex,2)
for i = 1:size(Vert_ID_mat,1)
if coordIndex(k,kk) == Vert_ID_mat(i) %isequal
Assoc_Colors{i} = Colors_Res(k, kk);
end
end
end
end
Assoc_Colors = Assoc_Colors.';
Assoc_Colors
% Vectorized method
coordIndexTrans = coordIndex.';
Colors_ResTrans = Colors_Res.';
[tf,loc]=ismember(Vert_ID_mat(:), coordIndexTrans(:),'legacy');
Assoc_Colors = cell(size(Vert_ID_mat));
Assoc_Colors(tf)=num2cell(Colors_ResTrans(loc(tf)))
1 commentaire
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Data Types dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!