MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn moreOpportunities for recent engineering grads.

Apply Today**New to MATLAB?**

Asked by .. Vamshi
on 23 Nov 2012

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

*No products are associated with this question.*

Answer by Harshit
on 23 Nov 2012

Accepted answer

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.

Show 2 older comments

.. Vamshi
on 26 Nov 2012

mmm... I want here to increment the count every time when the condition is met. Does the above piece of code satisfy my requirement?

Harshit
on 26 Nov 2012

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.

Answer by Akiva Gordon
on 23 Nov 2012

Also, try to avoid using `eval`. Look at this link to see why:

http://www.mathworks.com/matlabcentral/answers/51946-systematic-do-not-use-global-don-t-use-eval

## 0 Comments