less than against less or equal than

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Ioannis Vourvachakis 2021-11-2

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https://ww2.mathworks.cn/matlabcentral/answers/1577665-less-than-against-less-or-equal-than

评论： Ioannis Vourvachakis 2021-11-2

采纳的回答： Stephen23

Can someone tell me what is going on? Thank you

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Answer 1

Stephen23 2021-11-2

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https://ww2.mathworks.cn/matlabcentral/answers/1577665-less-than-against-less-or-equal-than#answer_822450

编辑：Stephen23 2021-11-2

在 MATLAB Online 中打开

"Can someone tell me what is going on"

Exactly as the comparison tells you, the value stored in that variable is greater than the literal 0.3060.

Such cases are easy to demonstrate:

A = 0.3060 + eps(1)
A = 0.3060
A > 0.3060
ans = logical
   1

Read more about binary floating point numbers:

https://www.mathworks.com/matlabcentral/answers/57444-faq-why-is-0-3-0-2-0-1-not-equal-to-zero

https://www.mathworks.com/matlabcentral/answers/316889-why-two-equal-numbers-are-not-equal

http://www.mathworks.com/matlabcentral/answers/102419-how-do-i-determine-if-the-error-in-my-answer-is-the-result-of-round-off-error-or-a-bug

http://www.mathworks.com/matlabcentral/answers/140656-about-numerical-difficulty-of-equality-comparison-operation-between-two-double-real-numbers-in-matlab

This is worth reading as well:

https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html

http://faculty.tarleton.edu/agapie/documents/cs_343_arch/papers/1991_Goldberg_FloatingPoint.pdf

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Steven Lord 2021-11-2

You can see this effect in real life too. Search Google or your favorite search engine for "Bill Gates net worth". When I did that Google told me he was worth 136.1 billion USD. Does that mean his net worth is exactly 136 billion 100 million USD and not a penny more? No. He could have an extra million or ten in his portfolio that Google didn't display.

Ioannis Vourvachakis 2021-11-2