engEvalaute[] does not return proper UTF-8 when using R2013a

[szhorvat]

Notice the "!" where we should see "中". When using 2012b on OS X I get the correct "中".

[szhorvat]

It seems this works correctly on:

• OS X R2012b, Linux R2013a

It fails on:

• OS X R2013a, Windows R2013a

Sending UTF-8 data to engEvaluate[] may crash on Windows R2013a which makes this issue more serious than just an annoyance.

[szhorvat]

To work around this on Windows (where it may cause crashes!) it may be necessary to wrap everything sent to MEvaluate[] in eval or evalc, like this (siplified):

MEvaluate[code_] := (MSet["code", code]; engEvaluate["s = evalc(code);"]; engEvaluate["clear code"]; MGet["s"])

Do you see any potential problems with this approach? Performance hits maybe?

Unicode in scripts may need to be handled differently.

[szhorvat]

Using evalc() disables JIT compilation and makes performance significantly worse. Thus it's not a viable solution.

Pasteable test code:

mEvaluate[code_String] := (MSet["code", code]; 
  MATLink`Engine`engEvaluate["result = evalc(code); clear code"]; 
  MGet["result"])

mEvaluate[" x=zeros(1e7,1);
  tic;
  for i=1:1e7
  x(i)=rand();
  end
  toc"]

MEvaluate[" x=zeros(1e7,1);
  tic;
  for i=1:1e7
  x(i)=rand();
  end
  toc"]

[szhorvat]

Worked around by using evalc() https://github.com/rsmenon/MATLink/commit/d5fe5437c443c108eb859e105926bd0cb81706a7

[rsmenon]

Since we reverted evalc for now (because it prints HTML errors & help), I'm reopening this. Also, it crashes on my OS X 10.8.3, MATLAB 2013a

[szhorvat]

Can you elaborate on the crash, and give an example to reproduce it?

[rsmenon]

MEvaluate["x='aéîøü'"] is sufficient to crash it. It gives a LinkObject::linkd error (which btw, is also on my todo list for today to return sensible errors)

[szhorvat]

It looks like unicode wouldn't work with several MATLAB or OS versions in the initial release anyway, so I am sending data to Mathematica as ASCII now. This will at least prevent crashes similar to what you saw.

https://github.com/rsmenon/MATLink/commit/fcceb71ef9387e2a7745c4737e733f481624844c

(binary not checked in for now, you'll need to recompile yourself)