Cannot run Mathematica C-interfacing examples 'factor'

Question

I am trying to run a Mathematica example concerning Mathematica interfacing issues with C programs. In particular I am trying to call a Mathematica function from C.

Example factor.c is the best in my case. As explained here at the Invoking the Mathematica Kernel from Within a Prebuilt Example section, I successfully build the examples (using the makefile through make all). After that I run the exaple as explained by typing:

./factor -linkmode launch -linkname 'math -mathlink'

But I get back to my shell after launching the program with no output as I did nothing. Then I try again just by launching ./factor, the program then asks me: Create link:, so I type 'math -mathlink', prfess ok, then it prompts: Integer to factor:, I type a 6 digit one and after that the program blocks (it waits for something, but after 5 minutes I kill it).

Consider that I am on Unix. My Mathematica installation is in this path /home/myuser/progs/Mathematica.... I run the example respectively with Mathematica running and not running. Same results.

How to make the example work?

Something strange

When I kill theprograms that I launch but stay on wait as I described before, it seems that they finally got killed, but it is not! When I try ps on my shell, they are there!!! Need to send SIGKILL to definetely get rid of them...

About links...

I bumped into a Mathematica function called LinkCreate. Maybe I need to run Mathematica, open a link from the interface, and then launch the example? I am trying some, so far no results, will keep on doing so...

Answer 1

I'm not sure why it doesn't work for you. Try using the full path to the kernel executable. The following works for me on OS X:

./factor -LinkMode Launch -LinkName '/Applications/Mathematica\ 9.app/Contents/MacOS/MathKernel'

I do have a symlink to MathKernel in a location that's in the PATH, but if I use that, as in ./factor -LinkMode Launch -LinkName math, it doesn't work here either. ./factor -LinkMode Launch -LinkName ~/bin/math (i.e. giving the full path) does work.

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If you want to start Mathematica separately (e.g. for understanding better what happens), do this:

Launch factor and at the Create link: prompt type any name. For this example, let's use mylink as the link name.

Then launch Mathematica in another terminal as math. Type link = LinkConnect["mylink"]. If it worked, type $ParentLink = link. Now you can use factor: type the number you want to factor and press enter.