[TRNSYS-users] TRNSYS 18 : type 169 python

[Brandon Hathaway]

Hi Antoine,

I experienced the same behavior, and was able to trace down the cause with
some digging into the Type169 source code.  In my case, it seemed that
specifying the name of the Python script alone, rather than the complete
path, was causing an issue when the code attempts to strip the script name
and script path into separate variables.  The variable "scriptPath"
contained just the name of the script, causing an undesired result when the
Type169 code attempts to execute a "sys.path.append()" command through
Python, resulting in the inability to Import the script.

I suspect that if you just specify the complete path to your script file in
the entry box within the TRNSYS Type169 Special Cards configuration tab,
rather than only the filename, the Type169 should work.  (However, the fix
I ended up using since I was already into the source code is described
below just in case anyone finds it helpful.)

In my case, I fixed the issue in the source code by commenting out the
existing line that executes the above mentioned command around line 267:

> // PyRun_SimpleString(scriptPath.c_str());


Then I added the following two lines which (1) import the OS module in the
Python session then (2) use that module to get the current working
directory and append it to the path:

> PyRun_SimpleString("import os");
> PyRun_SimpleString("sys.path.append(os.getcwd())");


After making those changes and recompiling the Type169.dll, my issue was
resolved when specifying just the name of a script within the current
working directory.  (Note, this makes it so that the script must ALWAYS be
within the current working directory, as the path/filename stripping part
of the code is now ignored.)

As for the TRNSYSpy module, it isn't a file, but is created within the
Type169 program and appended to the Inittab just before python is
initialized, which you'll see if you open the C++ source code around lines
262-264, so don't worry about that portion.

Best regards,
-Brandon

On Wed, Jul 1, 2020 at 4:12 AM Armandine Les Landes Antoine via
TRNSYS-users <trnsys-users at lists.onebuilding.org> wrote:

> Hello all,
>
>
>
> I am trying to use the python with the Type 169.
>
>
>
> Note that :
>
> -        Python 3 (3.7) is correclty installed and it is accessible from
> the cmd line.
>
> -        TRNSYS is installed to the root of C :
>
> -        Python is in the Windows path
>
> -        …
>
>
>
> I do not understand why nothing happen when I perform a simulation…
>
>
>
> I can not find anywhere the TRNSyspy module ??
>
>
>
> Could you provide an example of TRNSys using the Type 169 ? there is no
> example in TRNSYS18/Examples/.  such as Calling_Python ? that could help…
>
>
>
> Thank you for you help !
>
> Best regards,
>
> Antoine
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org
>
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