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.
显示 更早的评论
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
采纳的回答
Harshit
2012-11-23
1 个投票
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.
5 个评论
.. Vamshi
2012-11-23
Harshit
2012-11-23
% i=p:p+8
j = q:q+8
count1 = count1+sum(Theta_deg_img(i,j)>=-180 && Theta_deg_img(i,j)<=-135)
.. Vamshi
2012-11-26
Harshit
2012-11-26
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
2012-11-26
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