running bCpythondemo

Known Issues and Problems with BCI2000
dhruv aggarwal
Posts: 4
Joined: 08 Jun 2011, 23:15

running bCpythondemo

Post by dhruv aggarwal » 22 Jun 2011, 00:56

I am having some problem in running BCI python demos in the batch folder. I installed python using following instructions.

Install Python and all modules required by BCPy2000:
run install_all.bat
in directory src\contrib\BCPy2000, run Merge.bat
(see src/contrib/BCPy2000/framework/BCPy2000/Documentation/Building.html)

however, the error when I tried to run the demo were as following:

2011-06-22T10:06:38 - PythonSrcADC::Constructor: Failed to find a
dynamic library for python24 or python25. Is python installed?
2011-06-22T10:06:38 - PythonSigFilter::Constructor: Failed to find a
dynamic library for python24 or python25. Is python installed?
2011-06-22T10:06:38 - PythonAppFilter::Constructor: Failed to find a
dynamic library for python24 or python25. Is python installed?

I even tried to setup python parts manually (instead of using "install_all.bat"). Still the problem persists.
Kindly help.

Posts: 34
Joined: 17 Nov 2009, 15:15

Re: running bCpythondemo

Post by jhill » 22 Jun 2011, 11:33

While Python is nice and easy once it's running, Python installations themselves are complex things, and setup can get tricky as soon as you deviate from the prescribed procedure even a tiny bit. This is why I created the Fully Monty, a Python distro pre-loaded with everything you need. So you could try downloading that, instead of installing by hand. Read the doc first, on ... Monty.html , and then download under "Option A" on the download page and expand it under C:\.

If you want to set things up by hand, your error messages indicate that, one way or another, the python25.dll, which the BCI2000 binaries expect to find somewhere on the system Path, is not being found. I don't know why that is without looking at your system, but there are a few things to check:

Can you run Python in standalone manner?

Did you install Python "just for me" instead of "for all users"? I've had trouble with that before, and warn against it on the website.

Are you running Python 2.5? Or did you decide to substitute your own download of, say, 2.6 or 2.7? As the error message says, the release you have only looks for python25.dll and python24.dll by default: these are the only versions that are easily supported by the third-party packages such as VisionEgg on which we depend. But you can tell the binaries explicitly which DLL to look for by editing your batch file and adding flags:

Code: Select all

start PythonSource --PythonSrcDLL=whatever
start PythonSignalProcessing --PythonSigDLL=whatever
start PythonApplication --PythonAppDLL=whatever
"Whatever" can be the name of a DLL that's on the system Path, or it can also be a full path to the python DLL you want to use. But if Python somehow isn't set up correctly, you might also need to set the PYTHONHOME environment variable to the directory in which it lives, and also add that directory to the Path environment variable. This is all done for you in the Full Monty (in prog/portable.bat ).


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