Efficiently find a value in a matrix

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John Gilmore 2021-3-26

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评论： John Gilmore 2021-3-29

Hey all,

So I have a simple 1D matrix that I'm trying to find a specific value in. I know of a way to do it, but my main question is if anyone knows of a more effcient way? As of current, I'm using as part of an operation that occurs on the order of millions or even billions of times, and using the matlab profiler it's told me that this is far and beyond the most inefficient part of the whole process.

This is how I currently do it...the third line take up ~60% of my run time

DummyData = [1,3,5,7,9];
ValueToFind = 3;
[~,Index] = min(abs(DummyDaya - ValueToFind));

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Stephen23 2021-3-26

If you want to "find a specific value" why are you using code that just finds the closest value?

John Gilmore 2021-3-29

Ah yes, sorry, I should have been a bit more clear. This is doing what I want, particularly that's finding a specific value if it exists in the matrix. If it doesn't exist, then it finds the closest one.

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Answer 1

weikang zhao 2021-3-27

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From the perspective of computational complexity, your code can no longer be optimized. You can seek help from GPU acceleration or parallel computing.

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John Gilmore 2021-3-29

Yeah, that's sort of what I was unfortunately figuring. I guess I was wondering if anyone knew of more effcient built in functions, or maybe the built in functions have some bloat to them to make them more robust and someone knew of a smarter way to achieve the same result without using built-in functions.

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