How can I connect Mathematica to Clojure?

Question

I'm using Clojure and I'd really love to be able to use some of Mathematica's functions inside it. Can anyone help with mathlinking it?

Answer 1

To call Mathematica from Clojure, you will want to use Clojure's Java interop to access the Wolfram JLink classes to script Mathematica access.

Start by launching Clojure with a classpath that includes the JLink.jar, for example with this batch file:

@echo off
set MATHEMATICA=C:/M/9.0
set JLINKJAR=%MATHEMATICA%/SystemFiles/Links/JLink/JLink.jar
java -cp C:/Apps/clojure-1.4.0/clojure-1.4.0.jar;%JLINKJAR% clojure.main

Once inside Clojure, use the Java interop syntax to access JLink classes as described in the tutorial Writing Java Programs that Use Mathematica. Typically this starts by launching a kernel with the MathLinkFactory to obtain a KernelLink:

user=> (def kl (com.wolfram.jlink.MathLinkFactory/createKernelLink "-linkmode launch -linkname 'c:/M/9.0/math.exe -mathlink'"))
#'user/kl

Then discard the initial input packet from the kernel:

user=> (.discardAnswer kl)
nil

We can now perform evaluations of Mathematica code:

user=> (.evaluate kl "1+1")
nil
user=> (.waitForAnswer kl)
3
user=> (.getInteger kl)
2

When retrieving results from an evaluation, you need to know what type to expect, or you need to retrieve the result as a string and parse it.

Here's one way to evaluate a Mathematica expression that returns a list of integers and get the vector in Clojure:

user=> (.evaluate kl "RandomInteger[{0,99},20]")
nil
user=> (.waitForAnswer kl)
3
user=> (def res (vec (.getIntArray1 kl)))
#'user/res
user=> res
[91 12 98 20 71 43 59 64 98 64 20 93 32 84 41 90 38 27 51 76]

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There's also a presentation by Seth Chandler on connecting Mathematica to Clojure: J/Link without Java

Answer 2

I did not try it yet, but Clojuratica may be what you need. The project seems to no longer be maintained though (although I may be wrong). No idea how much of a problem this is, given changes in the Clojure since the time Clojuratica was released.

Of course, Seth's talk was also great and is a great resource as well, as Joel mentioned.