some questions about matlab coder

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matlabcoder 2018-4-24

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回答： matlabcoder 2018-5-1

Hi

I am doing my senior project on 5G simulations in matlab. We are doing the QAM using precoder and some modulation functions. We want to convert the code we have into C or C++. We used the matlabe code gen and we converted to C. We were surprised by how slow the C code is compared to matlab. It takes 260 sec for C to run one trial while only 90 sec on matlab. One of the thing we did is set the code gen to use dynamic allocation instead of static. I am looking for some recommendation or suggestions on how to produce a fast enough C code. Is that possible or we have to write the code fro scratch. Thanks

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Ryan Livingston 2018-4-27

编辑：Ryan Livingston 2018-4-27

MATLAB Coder added the ability for the generated code to call LAPACK in R2016a:

https://www.mathworks.com/help/coder/ug/generate-code-that-calls-lapack-functions.html

and FFTW in R2017b:

https://www.mathworks.com/help/coder/ug/speed-up-fast-fourier-transforms-in-generated-standalone-code-by-using-fftw-library-calls.html

Using these will give you optimized linear algebra and FFT routines respectively.

Walter Roberson 2018-4-27

Thanks for the update, Ryan.

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Answer 1

Ji Lee 2018-4-25

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Reducing the usage of dynamic memory allocation is one of the general optimization strategies one can start with when trying to improve the performance of generated code. We do have a useful documentation section that describes various optimizations and patterns. I've linked it below. Included in the first several topics linked from this section is a discussion on variable sizing and dynamic memory allocations.

https://www.mathworks.com/help/coder/optimize-speed-of-generated-code.html

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Answer 2

matlabcoder 2018-4-30

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Thank you all for the information, but I wonder why Mathworks doesn't push updates to include the features mentioned in Ryan comment.

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Answer 3

matlabcoder 2018-5-1

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The question is, is it possible to get the C code to run faster than the Matlab code, or it is possible that we have to write the whole code in C from scratch.