if statement question on two variables

there are two variables, f_x2(k)(1*50 double matrix, k=30), f_gbest all are equal to 7.9597,

but "f_x2(k) < f_gbest" returns TRUE!!!

Command History:

>> f_x2(k)

ans =

      7.9597

>> f_gbest

f_gbest =

      7.9597

>> f_x2(k) < f_gbest

ans =

       1

Why returns 1 ? Shouldn't it be 0?

Answer 1

[Roger Stafford]

Try this:

   format hex
   f_x2(k)
   f_gbest

You might be surprised by the result. Or else you can do this:

   fprintf(‘f_x2(k) = %25.20f  f_gbest = %25.20f\n’,f_x2(k),f_gbest)

[Steven Lord]

Or just look at the quantity

delta = f_gbest - f_x2(k)

The value stored in delta will be small but positive. Just because the number is only displayed with a small number of decimal places doesn't mean it's stored with only that small number of decimal places. To display more decimal places, see the help for the format function.