quick itteration

Hello ,

I want a better speed in operating my code ,if i did enter a large number of points like 10000 it will operate in 10 mins or more and my processor is good enough ,this code is plotting points in a uniform shape like rectangular and randomly with different x and y , thanks for attention.

%%

RN=input('Enter number of points =');

U1=[];U2=[];

for i=1:RN

xa=-L/2+L*rand(1,1)+0.2*rand(1,1)-.4;

ya=-N/2+N*rand(1,1)+0.2*rand(1,1)-.4;

xra(i)=xa;yra(i)=ya; z=[xra(i) yra(i)];

sub1=z(1);sub2=z(2);U1=[U1;sub1];U2=[U2;sub2];

    USERS=[U1 U2];

    figure(1)  

 plot(xra(i),yra(i),'k.');hold on

end

Answer 1

[Daniel Shub]

The best thing to do would be to move the plotting outside the loop:

...
end
figure(1);
plot(xra,yra,'k.');

[Ahmed Hassaan]

thanks

Answer 2

[Junaid]

Though your code requires cleaning but this code will generate exact output you are required. In your code there are many variables which are not required.

 RN=input('Enter number of points =');
  L=input('Enter the length x ='); 
  N=input('Enter the length y =');

U1=[];U2=[];

xa = -L/2+L*rand(RN,1)+0.2*rand(RN,1)-.4;
ya = -N/2+N*rand(RN,1)+0.2*rand(RN,1)-.4;

xra=xa;yra=ya; z=[xra yra];
sub1=z(:,1);sub2=z(:,2);U1=[U1;sub1];U2=[U2;sub2];

   USERS=[U1 U2];
   figure(1)  
   plot(xra,yra,'k.');

Answer 3

[Junaid]

I guess this can be done in one line without using for loop, and second line for plot. Could you tell us about L, N and other varibales you are using in side loop

[Ahmed Hassaan]

L=input('Enter the length x =');

N=input('Enter the length y =');

[Ahmed Hassaan]

L=input('Enter the length x =');

N=input('Enter the length y =');

[Daniel Shub]

Without having timed it, my guess is the time improvement from complete vectorization will be small compared to the use of a single plot.