counting column bits with the same weight in binary array

I have a binary array and I want to count the column with the same weight.

I want to do it with function...m-file

I hope that someone can help me to solve it.

Thanks Henry

[dpb]

Attach your data as text, not an image so someone can do something with it, specifically. But, your answers given don't coincide with the data by any stretch...

[Henry Buck]

For example:

19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0  
 0  0  0  0  1  0  0  0  0  0  0  0  0  1  1  0  1  1  0  0 
 0  1  0  0  0  1  0  0  0  1  1  0  1  0  1  0  1  1  0  1   
 1  0  1  0  0  0  1  0  0  0  1  1  1  0  1  0  0  0  1  1 
 0  0  1  0  0  1  0  1  0  1  0  0  0  1  0  0  1  0  1  1 
 1  1  0  0  1  0  0  0  1  0  1  1  1  1  0  0  0  0  0  1  
 0  1  1  1  1  1  0  0  1  0  0  0  0  0  0  1  0  0  0  0 
 0  0  1  1  1  1  1  1  0  1  0  0  0  0  0  1  1  1  1  0

There is 6 col with the same weight (two 1 bits) - col=0,3,6,7,11,15.

There is 8 col with the same weight (three 1 bits) - col=1,9,10,12,13,14,17,18.

There is 5 col with the same weight (four 1 bits) - col=2,4,5,16,19.

[dpb]

>> [0:size(a,2)-1;sum(a)]
ans =
0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19
2  3  4  2  4  4  2  2  2  3  3  2  3  3  3  2  4  3  3  4
>>

So, turns out not as far off as thought if you count from the left rather than using the header row as the column number. Other than missing one '2' (col 8), seems ok...

Answer 1

[dpb]

n=hist(sum(array),0:size(a,1));

N th element of n will contain counts for that number of bits from zero to size(array,1); ie, for all possible totals from no bits set to all.

ADDENDUM

>> [0:size(a,1);hist(sum(a),0:size(a,1))]
ans =
   0     1     2     3     4     5     6     7
   0     0     7     8     5     0     0     0
>> sum(ans(2,:))==size(a,2)  % sanity check...
ans =
   1
>>

Total number does equal number of columns in array...

Actually, there are 7,8,5 of wt=2,3,4, respectively.

[Henry Buck]

:-) Thanks a lot,

If I need to count a part of the matrix above -let say row3 to row6. What would I need to change/add instead of: [0:size(a,1);hist(sum(a),0:size(a,1))]

Thanks again, Henry

[dpb]

If it's a subset of rows, only the array indices to refer to the subset...

r1=3; r2=6;
n=hist(sum(array(r1:r2,:)),0:size(a,1));

[Henry Buck]

Hi dpb, It works perfectly. Thanks for your help, Henry