Floating point numeric problem

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Qian Feng
Qian Feng il 9 Dic 2016
Commentato: Star Strider il 17 Dic 2016
I encounter a problem which I cannot understand.
a = 1.228269:0.000001:1.22828;
b = 1.228265:0.000001:1.22828;
ismember(a,b)
>> ismember(a,b)
ans =
1×12 logical array
0 1 0 1 1 1 1 1 1 1 1 1
It is clearly to see that the logical array is not compatible with the values in vectors a and b. An expert has suggested that this has to do with the floating point numerics, do anyone can explain what happened to this example and how to we circumvent it ? Thanks a lot !

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Star Strider
Star Strider il 9 Dic 2016
What happened is best explained in: Why is 0.3 - 0.2 - 0.1 (or similar) not equal to zero?
You can circumvent it using the ismembertol function (in R2015a and later versions).
  4 Commenti
Qian Feng
Qian Feng il 17 Dic 2016
Thanks for the exposition here.
Star Strider
Star Strider il 17 Dic 2016
Our pleasure.

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