difficulty filter file with big data

I need of help me with this script. I want to filter all the columns but this is very slow.

there I have filtered only two columns.

My file loaded is only example.

clear all 
clc
tic
a = 1;
r = zeros(3268760,1); 
load ('filter_big_data'); % this file ís a matrix 576x3268760 double
for i = 1:2
    z1 = b(b(:,1) == 0, :); 
    s1 = sum(z1, 1);
    s2 = max(s1);
    r(a,1) = max(s1);
    a = a + 1;
end
toc

Elapsed time is 209.340817 seconds. % this time was elapsed for to filter two columns of

Thank by attention!!!

[Walter Roberson]

load filter_big_data
whos

  Name       Size                     Bytes  Class     Attributes

  ans        1x43                        86  char                
  b         10x3268760            261500800  double              

You do not have any array named a.

You override the b=1 when you load the file, getting b to be a 10 x 3268760 array.

[AIRTON]

Hy Walter

you have reason!

I have changed my script.

Can you help me, I am inexperient with Matlab. I am learning.

Thanks!

[Walter Roberson]

    z1 = b(b(:,1) == 0, :); 

That code does not depend on a or i so it is going to produce the same result for every iteration of the loop. Because of that, every iteration of the loop is going to perform the same operation.

I would suggest that the code should be closer to

tic
r = zeros(3268760,1); 
load ('filter_big_data'); % this file ís a matrix 576x3268760 double
for i = 1:2
    z1 = b(b(:,i) == 0, :); 
    s1 = sum(z1, 1);
    s2 = max(s1);
    r(i,1) = max(s1);
end
toc