MATLAB Answers

Getting wrong results while calling a function.

7 views (last 30 days)
Asif Rahman
Asif Rahman on 2 Sep 2021
Commented: Rik on 3 Sep 2021
I have written a simple function. It takes two inputs, only when two inputs are equal the output should be zero.
function I = getI(E,Eg)
if (E<=1.5) && (E ~= Eg)
I=(500*E)/1.5;
elseif (E>1.5) && (E<=4) && (E ~= Eg)
I=500*(1-((E-1.5)/(4-1.5)));
elseif (E==Eg)
I=0;
end
end
Now the function works as expected most of times,but when the value of Eg is 1.38,1.39,1.4, 2.84 or 2.6 the code doesnot gives I=0 even when the value of Eg is equal to E. Example:
I tried changing the if conditions, changing their positions. No change.

Answers (1)

Rik
Rik on 2 Sep 2021
Some numbers cannot be represented exactly in binary. You will either need to round both numbers to make sure they have the exact same representation, or compare the differences to a tolerance.
  2 Comments
Rik
Rik on 3 Sep 2021
This shows the correct result, because the numbers are generated the same way.
If a number can't be represented exactly by a double, it might be represented slightly differently if the method of calculation is different, e.g. writing 1.4 directly and using the colon operator.

Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by