Technical Solutions

Why do my numbers not add up correctly in MATLAB?

Date Last Modified: Friday, June 26, 2009

Solution ID:		1-536M9L
Product:		MATLAB
Reported in Release:		No Release
Platform:		All Platforms
Operating System:		All OS

 

Subject:

Why do my numbers not add up correctly in MATLAB?

Problem Description:

When I add numbers together, and then compare the result to a number that I think is the correct result using "==" or the ISEQUAL function, the comparison returns as "false" or 0.
For example:
a = 0.1 + 0.1 +0.1;
b = 0.3;
a == b


ans =

     0

Solution: This behavior is related to floating-point arithmetic and the way numbers are represented in a computer. For more information on this subject, see the related Solution below.

 

Related Solutions:

• How do I determine if the error in my answer is the result of round-off error or a bug?

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