How does MATLAB compare numbers?

I am using a while loop in my code shown below. Sometimes the program is entering the while loop even if a=b. I am inputting value b and the value of a is updated from the code show below. This is happening when let's say b=2 and a=2.0000. MATLAB is not correctly taking a=b.

Do I need to change significant digits?

while (a<b)                                                  
      integral = integral+(h/2)*(f(a)+f(a+h));
      a=a+h;
end

Answer 1

[Star Strider]

‘Do I need to change significant digits?’

You may need to understand how floating-point approximation works. See Why is 0.3 - 0.2 - 0.1 (or similar) not equal to zero? for a thorough discussion.

Rounding to a specific number of decimal places could help, but that itself is the result of a floating-point calculation and is not certain to produce the result you may want. It may be better to allow for a tolerance in your comparisons.

Also, please do not use ‘integral’ as a variable name, particularly if you have R2012a or later. It is the name of a function that does numerical integration. This is called ‘overshadowing’ of the built-in function and is best avoided.