How can I reduce the time complexity of this matlab code.. Its taking lot of time to execute when an image is fed as input.

조회 수: 2 (최근 30일)
cnt1=0; cnt2=0; cnt3=0; cnt4=0; cnt5=0; cnt6=0; cnt7=0; cnt8=0;
p = 1;
row = 1;
while p<(size(Theta_deg_img,1))
q = 1;
while q<(size(Theta_deg_img,2))
for i=p:p+8
for j=q:q+8
if Theta_deg_img(i,j)>=-180 && Theta_deg_img(i,j)<=-135
cnt1 = cnt1+1;
elseif Theta_deg_img(i,j)>=-134 && Theta_deg_img(i,j)<=-90
cnt2 = cnt2 + 1;
elseif Theta_deg_img(i,j)>=-89 && Theta_deg_img(i,j)<=-45
cnt3 = cnt3 + 1;
elseif Theta_deg_img(i,j)>=-44 && Theta_deg_img(i,j)<=0
cnt4 = cnt4 + 1;
elseif Theta_deg_img(i,j)>=1 && Theta_deg_img(i,j)<=45
cnt5 = cnt5 + 1;
elseif Theta_deg_img(i,j)>=46 && Theta_deg_img(i,j)<=90
cnt6 = cnt6 + 1;
elseif Theta_deg_img(i,j)>=91 && Theta_deg_img(i,j)<=135
cnt7 = cnt7 + 1;
else
cnt8 = cnt8 + 1;
end
eval([fsrc '(row,1) = cnt1;']);
eval([fsrc '(row,2) = cnt2;']);
eval([fsrc '(row,3) = cnt3;']);
eval([fsrc '(row,4) = cnt4;']);
eval([fsrc '(row,5) = cnt5;']);
eval([fsrc '(row,6) = cnt6;']);
eval([fsrc '(row,7) = cnt7;']);
eval([fsrc '(row,8) = cnt8;']);
end
end
q = q + 9; row = row+1;
cnt1=0; cnt2=0; cnt3=0; cnt4=0; cnt5=0; cnt6=0; cnt7=0; cnt8=0;
end
p = p + 9;
end

채택된 답변

Harshit
Harshit 2012년 11월 23일
Vectorize your code. Example you don't need inner loops you can use sum to get the value of counts. In the outer two loops you are calculating size again and again. Store it in a variable.
  댓글 수: 5
Harshit
Harshit 2012년 11월 26일
Yes it will just think about it. Whenver the condn is true 1 will be generated in the matrix and otherwise 0. sum will give the no of 1.
.. Vamshi
.. Vamshi 2012년 11월 26일
I followed your suggestion.. the counts have to be stored for every iteration.. but here am unable to do..

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Akiva Gordon
Akiva Gordon 2012년 11월 23일

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