how to fill gaps in a matrix with a numbers using interpolation to develop a contour.

M =
     0     0     0
     0     0     3
     0     3     0
     3     0     3
     0     3     0
     0     0     3
     3     0     0
     0     0     0

in this M matrix, using interpolation i want to fill gaps with 3s between any 3s. for example, in first column, first 3 is in the 4th row and last 3 is in the 7th row. i want to fill rows 5 and 6 also with 3s. same for other columns.

Thanks and regards for all cooperation

[awezmm]

Do you need to find gaps horizontally too, or only vertically?

Answer 1

[Andrei Bobrov]

M(cumsum(M) & cumsum(M,1,'reverse')) = 3;

or for:

M =[0 0 0; 2 2 3; 3 3 0; 0 0 0; 3 3 0; 2 2 3; 0 0 0; 3 3 2; 0 0 0; 3 3 3];

s = join(string(M)','');
[a,b] = regexp(s,'30+3');
lo = false(size(M));
for ii = 1:numel(a)
    for jj = 1:numel(a{ii})
        lo(a{ii}(jj)+1:b{ii}(jj)-1,ii) = true;
    end
end
M(lo) = 3;

[M.S. Khan]

Thanks bro Andrei for your continuous contributions in the research. Warm regards.

Answer 2

[KALYAN ACHARJYA]

M =[0     0     0
     0     0     3
     0     3     0
     3     0     3
     0     3     0
     0     0     3
     3     0     0
     0     0     0]
 [rows colm]=size(M);
 for i=1:colm
 idx=find(M(:,i)==3);
 idx_update=idx(1):1:idx(end);
 M(idx_update,i)=3;
 end
 M

Loop can be avoided. Wait for experts comments.

Result:

M =

     0     0     0
     0     0     3
     0     3     3
     3     3     3
     3     3     3
     3     0     3
     3     0     0
     0     0     0

[KALYAN ACHARJYA]

M =[0 0 0; 2 2 3; 3 3 0; 0 0 0; 3 3 0; 2 2 3; 0 0 0; 3 3 2; 0 0 0; 3 3 3] 
[rows colm]=size(M);
 for i=1:rows-2
 for j=1:colm
 if (M(i,j)==3 && M(i+2,j)==3)
 M(i+1,j)=3;
 end 
 end
 end
 M

Unabled to fixed it without loop. wait for experts answer.

Just I saw that you have posting duplicate question., Please donot post multiple same question, people invest their important time on user question.

[M.S. Khan]

Mr. Kalyan, 3rd column is not changed.

[KALYAN ACHARJYA]

Your comment:

"i mean to fill 3s only only 3 and then the next 3, not in all."

There is no 3 0 3 combination in the 3rd column.

[M.S. Khan]

Mr. Kalyan, 3 and next 3 positions should be filled with 3s. For example 3 0 0 0 0 3. So it should be 3 3 3 3 3 3.

[awezmm]

Can the gaps only be in a single column?