Is it a bug?

I found a weird situation with the number "1.4"

v=0:0.01:5;
vd=1.4;
a=0;

for i=1:length(v)

    if v(i)==vd
        a=1
    end
    
end

This code doesn't make the value of "a" become "1." However, if I change the value of "vd" to any other numbers (eg. vd=1.5), this code works well. Also, if I change the range of "v" to "v=0:0.01:2", it works as well. I don't know what's wrong with my orignal codes. Can anyone help me? Thank you very much!

Answer 1

[Star Strider]

You have encountered ‘floating-point approximation error’.

See Floating-Point Numbers for an extended discussion.

Also see colon for an explanation of how it calculates the numbers in your ‘v’ vector.

Answer 2

[Image Analyst]

Yes, you do have a bug in your program.

You compared floating point numbers with == instead of ismembertol().

See the FAQ for fixes.

[Star Strider]

+1