how to velocize execution code

 load('matlab_v1.mat')
  load('matlab_v2.mat')
  
 [r,c]=size(v1);
   res=zeros(size(v1));
   t=0;
  for i=1:c
    for ii=1:r  
     a=v1(ii,i);
     b=v2(ii,i);
    
     if a
       t=0; 
     end    
     if b 
        t=1;
     end    
     Res(ii,i)=t;
    end  
  end
  
  
%explanation:
%When v1=1 then i set=0 Res until the end 
%When v2=1 then i set=1 Res until the end

it's possibile to velocize it avoid loop (using vectorizing or other)

[Walter Roberson]

     if a
       t=0; 
     end    
     if b 
        t=1;
     end    

It is possible that a is 0 and b is also 0. In that case, t will remain unchanged. That makes it more difficult to vectorize, since you have to copy the previous t .

[Luca Re]

yes..that's correct

Answer 1

[Walter Roberson]

 load('matlab_v1.mat')
 load('matlab_v2.mat')
 res = nan(size(v1));
 res(v1 ~= 0) = 0;
 res(v2 ~= 0) = 1;
 res = reshape(fillmissing( res(:), 'previous', 'EndValues', 0), size(res));
 

[Luca Re]

thank..very good...is more speed

[Luca Re]

using this data your code is not correct

your solution is not equal to this my code

[r,c]=dimensione(v1);
   res=zeros(dimensione(v1));
   t=0;
  per i=1:c
    per ii=1:r  
     a=v1(ii,i);
     b=v2(ii,i);
    
     se un
       t=0;
     FINE    
     se b
        t=1;
     FINE    
     Res(ii,i)=t;
    FINE  
  FINE
  

Answer 2

[Jatin]

Hi Luca,

As per my understanding, you are trying to fill a new logical array “res” which is assigned a value of 0 if the logical array “v1” has a value 1 and assigned a value 1 if the logical array “v2” has a value 1.

The above requirement can be easily vectorized in MATLAB using logical indexing of arrays. Refer the script below:

res = zeros(size(v1)); 
% Logical indexing to set values based on conditions 
res(v2) = 1;  % Set to 1 where v2 is true 

The assignment of “res” using “v1” is not necessary because “res” is already initialized to all zero so assignment of “0” is redundant here.

Note: If you are trying to assign the values of res as a switch where you keep on assigning a value 1 until you encounter “v1 = 1” and assign value 0 until you encounter “v2 = 1”. In this case the current assignment results depend on the previous state and hence vectorized assignment cannot be done.

You can refer the documentation below for information on “Array Indexing on logical values”:

https://www.mathworks.com/help/matlab/math/array-indexing.html#MatrixIndexingExample-3

[Luca Re]

my problem is that when I encounter v1=0 write all or....When I encounter v2=1 I write all 1..How would you code it without looping?

[Stephen23]

"How would you code it without looping?"

Why?

[Luca Re]

because I have a lot of data and I thought it could be speeded up easily

[Stephen23]

"because I have a lot of data and I thought it could be speeded up easily"

I doubt that doing this without a loop would be faster.

What would make your code faster is fixing the name Res / res.

[Luca Re]

if it could be vectorized it would be faster but I see that it doesn't work

[Luca Re]

excuse me but you write "What would make your code faster is fixing the name Res / res."

why uppercase is more slow of lowercase?

[Star Strider]

MATLAB is case-sensitive. So ‘res’ is not the same as ‘Res’. They are entirely different variables.

[Jatin]

"why uppercase is more slow of lowercase?"

Stephen23 pointed out that using "res" instead of "Res" can enhance speed because "res" is already pre-initialized in your code. Since "Res" was not pre-initialized, every time you assign values to it, memory has to be dynamically allocated, which adds overhead. By pre-initializing "res," you avoid this overhead, saving time in your operations.

[Luca Re]

ok thank you