Remove row from matrix that doesn't meet if condition

f=@(x) 2-2*x(1)-x(2) %%Check admissibility
for j=1:size(sol,1);

      z=sol(j,1:2)
      if f(z)>=-1
          fprintf('Admissible')
          check(j)=0;
      else fprintf('Not admissable')
          check(j)=1;
      end
  end

for j=1:size(sol,1)  %%Remove non admissible rows from solutions
    if check(j)==1
     sol(j,:)=[];  
    end 

end

Hi, I am trying to check if the variable value stored in the first two columns of the matrix sol =

[  0,  0,   0,   0,   0]
[  1,  0,  -1,   0,   0]
[  0,  2,   4,   0, -10]
[  6, -2,   0,  10,   0]
[  0,  4,   0,  -8, -12]
[ -2,  6, -16, -30,   0]

satisfy the inequality on f, and, if not, delete the relative row.

I've written the code above, but the problem is that when one row is canceled the dimensionality of the matrix is altered and everything goes awry (unless the row to be deleted is the last one).

How can I fix this?

Answer 1

[Jan]

If you delete the 1st column of sol, deleting the 2nd requires:

sol(1, :) = []
% not sol(2, :) = [] !!!

because the new 1st row is the old 2nd one already.

Better omit the loop:

sol(check == 1, :) = [];