# How to execute an existing notebook with Wolfram Engine?

[My related question: mwe-for-compiling-functions-into-standalone-dll-and-calling-them-in-python - here I am exploring an alternative]

I have downloaded, installed and activated the wolfram engine (12.0) on Windows, and I have installed the WolframClient in my Python environment.

In python I execute

from wolframclient.language import wl
from wolframclient.evaluation import WolframLanguageSession
kernelLoc = 'C:\\Program Files\\Wolfram Research\\Wolfram Engine\\12.0\\WolframKernel.exe'
session = WolframLanguageSession(kernelLoc)
session.evaluate(wl.StringReverse('abc'))


and the result is 'cba' proving that the integration is working.

I have a workbook that contains all my (valid) compilable functions.

Question: how do I load & evaluate that notebook and call the compiled functions? (I could use a package file instead if that would help)

I have not (yet) found the answer by reference to the Wolfram Client documentation

Side issue: I recall that setting up my MMA 11.0.1.0 to work with Visual Studio 2017 for C compilation was... tricky. Does the Wolfram Engine have independent setup and if so how do I apply the working config for compilation from MMA to WE? Of course, if I can load the required notebook and it just works then this becomes redundant, but... expect the not-to-be-unexpected is my motto for development.

Update

Loading a Notebook requires FrontEnd, which is not available; I tried to import using NotebookImport, passing a filename and using "Input" as the style filter but also to no avail

using

nbPath = 'A:\\My Documents\\...\\ctXi_WolframEngine.nb'
mynb = session.evaluate(wl.NotebookImport(nbPath,'Input'))
mynb


I got this, which is clearly not helpful

(HoldComplete[None],
HoldComplete[None],
HoldComplete[None],
HoldComplete[None],
Failure['InterpretationFailure', {'CellStyle': 'Input', 'ContentData': BoxData, 'Cell': RawBoxes[Cell[BoxData['~'], 'Input', Rule[CellChangeTimes, (3771391298.009615,)]]]}],
HoldComplete[None],
...


Note that the notebook works perfectly well in Mathematica itself.

• You can open a notebook with wolframplayer (in Executables of your Wolfram Engine installation folder) and copy/paste the code. – Fortsaint Nov 25 '19 at 0:15
• @Fortsaint How would I connect to wolframplayer from Python in order to pass parameters and execute functions? – Julian Moore Nov 25 '19 at 21:21
• Did you try NotebookImport[ .. , _->"Text" ] ? – Fortsaint Dec 4 '19 at 15:47

Provided that \$Path contains an appropriate path to a package CTMisc.m the following works

session.evaluate(wlexpr('Needs["CTMisc"]'))


Then I was able to successfully call a function yyyymmddhhmmssmsDateString[milliseconds_] defined in that package

t = session.evaluate(wlexpr('yyyymmddhhmmssmsDateString[3407800000]'))
print(t)

1900-02-09 10:36:40.000


One must be careful with the expression of strings: contexts as strings are usually written as "MyContext" in Mathematica. I had a problem when I was trying to be too literal and declared

pkgName = '"MyContext"'


Specified correctly one can also write e.g.

session.evaluate(wl.Get("MyContext"))


The following function was defined in the package:

compiledTestFunction =
Compile[{{n, _Real}, {m, _Real}},
Module[{},
Return[n * m]
];
CompilationTarget->"C", "RuntimeOptions"->"Speed"];


After Get-ting the package we define the Python function and then execute

compiledTestFunctionPython = session.function('compiledTestFunction')
compiledTestFunctionPython(2.0, 7.0)


and the result is as expected, 14.0

Conclusion: Wolfram Engine on Windows 10 with Visual Studio 2017 worked out of the box for C compilation on this MWE.