Comparison among numbers, pls help!

Good morning guys,

I have a strange issue with my matlab code.

I have two Matrix and I need to compare a specic row of the first matrix with a specific of the second one.

I know they are equal but I need matlab check it for me!

In the first step i defined the two matrixs and than I asked to check the equality. This second step is shwn in the figure below and I have already checkd they are numbers and not strings.

How it is possible ? How can I correct this problem?

TY in advance

[Atsushi Ueno]

format long

You can see the comparing is more accurate.

[Alcide Bertocco]

Ty very much, I will try

Answer 1

[Adam Danz]

The difference is likely due to round-off error due to floatling point representation

To test for equality while ignoring round-off error, instead of A==B or isequal(A,B),

abs(A-B) < 1e4*eps(min(abs(A),abs(B)))

References & Examples

• Recognize and Avoid Round-Off Errors
• How can I compare numbers for equality within a tolerance
• Increase Precision of Numeric Calculations
• Floating Points: IEEE Standard Unifies Arithmetic Model
• Floating Point Numbers
• Example
• Another example
• Exploring Rounding Errors in Matlab Using Extended Precision - article
• What Every Computer Scientist Should Know About Floating-Point Arithmetic