Help optimizing/vectorizing a code in which loops are used to fill several vectors
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Hello,
I'm trying to fill in several vectors from the info that I have on a text file. I load the different columns of that file o severall Arrays A, B, C, D, E, F, and G.
The size of my vectors is quite big, (10^6 or 10^7) elements so the code I show next takes a long time to run.
Can someone help me with a vectorization of this in order to make it faster?
[A,B,C,D,E,F,G] = textread(strcat(PathName,FileName),'%f %d %d %d %d %s %s');
n=size(A,1);
for i=1:n
if C(i) == 0 && D(i) == 0
prim(i)=A(i);
elseif C(i)==0 && D(i) ~= 0
sc(i)=A(i);
elseif C(i)~=0 && C(i) ==0
sc2(i)=A(i);
end
if C(i)+D(i)==1
o1(i)=A(i);
elseif C(i)+D(i)==2
o2(i)=A(i);
elseif C(i)+D(i)==3
o3(i)=A(i);
elseif C(i)+D(i)==4
o4(i)=A(i);
elseif C(i)+D(i)>4
osup(i)=A(i);
end
end
1 Comment
Kevin Holst
on 31 Jul 2012
I haven't looked into your code too much but I believe this line is incorrect anyways:
elseif C(i)~=0 && C(i) ==0
shouldn't it be:
elseif C(i)~=0 && D(i) ==0
Accepted Answer
John Petersen
on 31 Jul 2012
Here's one way to do it
sc = [];
i = (~C & D);
sc(i) = A(i);
o3 = zeros(n,1);
CpD = C + D;
i3 = find(CpD ==3);
i4 = find(CpD ==4);
o3(i3) = A(i3);
o4(i4) = A(i4);
Follow similar logic for the rest of your code.
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