Where is 'cmatches.m'?
If you download 'sampen.m' only, you will encounter this error when you try
to run it:
??? Undefined function or method 'cmatches' for input arguments of type
'double'.
Error in ==> sampen at 51
[match,R]=cmatches(y,n,r);
There is no 'cmatches.m', because this function is provided by C code that
has been compiled into 'cmatches.dll'. If you are using Matlab on Windows,
you can download and use
http://physionet.org/physiotools/sampen/matlab/1.1/cmatches.dll
This solution is only usable on compatible 32-bit versions of Windows.
Alternatively, you can use a pure Matlab version of cmatches by downloading
http://physionet.org/physiotools/sampen/matlab/1.1/sampenc.m
which will work on all platforms. After downloading 'sampenc.m', run 'sampen'
but set its fifth input argument (cflag) to 0; this will cause it to bypass
cmatches and use sampenc instead. Read 'sampen.m' to see how this works.
A third method is to download, compile, and run
http://physionet.org/physiotools/sampen/c/sampen.c
If you do this, also download the other files in
http://physionet.org/physiotools/sampen/c/
which include a 'Makefile' to simplify compilation and testing.
The C code is significantly faster than the Matlab code, and it works on all
platforms. 'cmatches.dll' is based on the code in sampen.c.