MATLAB: Has typecast become efficient in current Matlab versions

performanceshareddatacopyspeedtypecast

In older Matlab versions typecast created a copy of the data. The FileExchange submission FEX: typecastx creates a shared data copy instead, such that no additional memory is allocated, which is much faster for large arrays.

Does typecast of modern version become more efficient by using shared data copies?

I'm still using R2011b for certain reasons and cannot test this by my own.

Best Answer

Yes. See http://blogs.mathworks.com/steve/2015/08/07/typecast-got-faster-in-r2014b/

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MATLAB: Output of mod() for large input

@Walter Roberson is correct, in R2012a MATLAB automatically casts the number into a uint64. For this piece of code

[mod(25754210418041856,179424673), mod(uint64(25754210418041856),179424673)]

In R2011b I get this:

            149629568            149629566

In R2012a I get this:

            149629566            149629566

MATLAB: Slow plotting performance starting from Matlab R2014b

The difference between the two versions is really a bit too complex to capture in a single number. I've been going into some of the details on the MATLAB Graphics blog.

My guess from your example is that what you're seeing is marker drawing performance. I don't think that I've covered that one well in the blog. The short version is that all of the graphics functions now share a single marker drawing implementation. This new version is faster than some of the old ones (e.g. the scatter example in this post ), but slower than the fastest of the old ones (which is the one you'd be getting here with plot). We're still working on tuning this up, and you should see some improvements as each new release comes out.

The one special case in marker drawing which is important to know about is that the '.' marker translates directly to an OpenGL primitive, and is much faster (and uses less memory) than all of the others which require a lot of shimming.

Best Answer

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MATLAB: Output of mod() for large input

MATLAB: Slow plotting performance starting from Matlab R2014b

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