Merge pull request #101 from Galvant/feature-matlab

Initial MATLAB fn and example.

matlab/matlab-example.ipynb

@@ -0,0 +1,79 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Loading Instruments from MATLAB #"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "MATLAB 2016a supports calling into Python, such that we can open instruments and communicate with them from within MATLAB applications. This takes a little bit of work, however, due to bugs in MATLAB's Python interface. Here, we'll demonstrate using the ``open_instrument.m`` MATLAB function to open instruments from their URIs."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stderr",
+     "output_type": "stream",
+     "text": [
+      "\n",
+      "  File build/bdist.linux-x86_64/egg/serial/serialposix.py, line 294, in open\n",
+      "\n",
+      "  File build/bdist.linux-x86_64/egg/serial/serialutil.py, line 180, in __init__\n",
+      "\n",
+      "  File build/bdist.linux-x86_64/egg/instruments/abstract_instruments/comm/serial_manager.py, line 64, in new_serial_connection\n",
+      "\n",
+      "  File build/bdist.linux-x86_64/egg/instruments/abstract_instruments/instrument.py, line 438, in open_serial\n",
+      "\n",
+      "  File build/bdist.linux-x86_64/egg/instruments/abstract_instruments/instrument.py, line 355, in open_from_uri\n",
+      "\n",
+      "  File <string>, line 1, in <module>\n",
+      "Python Error: SerialException: [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'\n",
+      "\n"
+     ]
+    }
+   ],
+   "source": [
+    "instrument = open_instrument('phasematrix.PhaseMatrixFSW0020', 'serial:/dev/ttyUSB0')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": true
+   },
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "MLegacy Kernel",
+   "language": "python",
+   "name": "kernel_mlegacy"
+  },
+  "language_info": {
+   "file_extension": ".m",
+   "help_links": [
+    {
+     "text": "MetaKernel Magics",
+     "url": "https://github.com/calysto/metakernel/blob/master/metakernel/magics/README.md"
+    }
+   ],
+   "mimetype": "text/x-matlab",
+   "name": "matlab"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}

matlab/open_instrument.m

@@ -0,0 +1,30 @@
+function instrument = open_instrument(name, uri)
+% open_instrument Opens an instrument given its InstrumentKit URI.
+%
+% WARNING: this function can execute arbitrary Python code, so do *not*
+% call for untrusted URIs.
+
+    % We need to use py.eval, since using py.* directly doesn't work for
+    % @classmethods. This presents two drawbacks: first, we need to manage
+    % the Python globals() dict directly, and second, we need to do string
+    % manipulation to make the line of source code to evaluate.
+
+    % To manage globals() ourselves, we need to make a new dict() that we will
+    % pass to py.eval.
+    namespace = py.dict();
+
+    % Next, py.eval doesn't respect MATLAB's import py.* command-form function.
+    % Thus, we need to use the __import__  built-in function to return the module
+    % object for InstrumentKit. We'll save it directly into our new namespace,
+    % so that it becomes a global for the next py.eval. Recall that d{'x'} on the
+    % MATLAB side corresponds to d['x'] on the Python side, for d a Python dict().
+    namespace{'ik'} = py.eval('__import__("instruments")', namespace);
+
+    % Finally, we're equipped to run the open_from_uri @classmethod. To do so,
+    % we want to evaluate a line that looks like:
+    %     ik.holzworth.Holzworth.HS9000.open_from_uri(r"serial:/dev/ttyUSB0")
+    % We use r to cut down on accidental escaping errors, but importantly, this will
+    % do *nothing* to cut down intentional abuse of eval.
+    instrument = py.eval(['ik.' name '.open_from_uri(r"' uri '")'], namespace);
+
+end