argmin of a vector

Question

etcann 2012-2-17

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https://ww2.mathworks.cn/matlabcentral/answers/29377-argmin-of-a-vector

回答： Heather Jones 2018-8-5

Hello,

How can I pick up the argmin of a vector? I.e. In a vector such as a=[2 3 1 4 5], I want to pick up 1 by min(a) and also want to have 3 that is the Nth element of this vector with the minimum 1. I tried to use find(a=min(a)) but the find operator is not working with equality.

Thanks

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Answer 1

James Tursa 2012-2-17

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From the documentation for the min function:

[C,I] = min(...) finds the indices of the minimum values of A, and returns them in output vector I. If there are several identical minimum values, the index of the first one found is returned.

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Answer 2

Walter Roberson 2012-2-17

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If find is not working with equality then your values are probably not what you think they are:

http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F

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Answer 3

Heather Jones 2018-8-5

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The expression find(a=min(a)) is not valid. Try using == (which is used when testing equality) instead of = (which sets the left hand side equal to the right). find(a==min(a)) should work.