Using emlc to generate C code - function within a function problem
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Hello fellow Matlab users,
Ive been trying to convert a massive code from matlab to c and implement it for real time signal processing on a DSP processor.
So far ive been succesfull and emlc is an amazing function! The problem i have reached now is that I need to compile a code that has the function "butter" inside (gives out butterworth filter coefficients.)
The problem is that the compilation report complains about butter`s input arguments are not constant.
To make things a bit more clear:
C_generating_script.m => Function_1.m => butter.m
Now my question is:
How can I define/declare the inputs of the butter function as constants which is within another function and allow it to compile?
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Kaustubha Govind
il 24 Feb 2011
Have you tried specifying constant inputs using emlcoder.egc: http://www.mathworks.com/help/toolbox/eml/ug/bq2wkmb-47.html#brl11_g-1
2 Commenti
Kaustubha Govind
il 25 Feb 2011
Could you give a simple example of what you are doing? I tried the following, and it compiled without using emlcoder.egc:
-------- mytest.m ----------
function [b, a] = mytest
%#codegen
n = 4; Wn = 0.5;
a = zeros(1,5);
b = zeros(1,5);
[b a] = subfun(n,Wn);
-------- subfun.m ----------
function [b a] = subfun(n, Wn)
%#codegen
[b a] = butter(n, Wn);
Più risposte (3)
Andreas Prokopiou
il 27 Feb 2011
1 Commento
Kaustubha Govind
il 28 Feb 2011
You should use:
emlc -eg {emlcoder.egc(dt),fasterdt,CF_of_channel,audiotimeofblock } MAP_ParamGen.m -c -T RTW -report
To specify that 'dt' as a constant, since this determines one of the inputs to butter.
Andreas Prokopiou
il 1 Mar 2011
2 Commenti
Kaustubha Govind
il 1 Mar 2011
Did you try by specifying all relevant inputs: dt and OMEfilters as constant inputs using emlcoder.egc?
Fred Smith
il 14 Lug 2011
Try using eml.unroll on the for-loop. That will cause the loop to be unrolled in the generated code.
This may or may not be acceptable depending on how many iterations the loop has. If it is not acceptable then you need a butter function that supports non-constant inputs. That capability is not available today.
If that is what you need, could you explain your use case and we'll create an enhancement request to add this capability to the product.
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