specify the build options using the -o flag. Updated docs and example notebook

doc/misc.rst

@@ -37,6 +37,8 @@ and then use the ``%%cl_kernel`` 'cell-magic' command. See `this notebook
 <http://nbviewer.ipython.org/urls/raw.githubusercontent.com/pyopencl/pyopencl/master/examples/ipython-demo.ipynb>`_
 (which ships with PyOpenCL) for a demonstration.
 
+You can pass build options to be used for building the program executable by using the ``-o`` flag on the first line of the cell (next to the ``%%cl_kernel`` directive). For example: `%%cl_kernel -o "-cl-fast-relaxed-math"``.
+
 .. versionadded:: 2014.1
 
 Guidelines

examples/ipython-demo.ipynb

@@ -106,7 +106,7 @@
      "cell_type": "code",
      "collapsed": false,
      "input": [
-      "%%cl_kernel\n",
+      "%%cl_kernel -o \"-cl-fast-relaxed-math\"\n",
       "\n",
       "__kernel void sum_vector(__global const float *a,\n",
       "__global const float *b, __global float *c)\n",

pyopencl/ipython_ext.py

@@ -33,7 +33,9 @@ class PyOpenCLMagics(Magics):
             raise RuntimeError("unable to locate cl context, which must be "
                     "present in namespace as 'cl_ctx' or 'ctx'")
 
-        prg = cl.Program(ctx, _try_to_utf8(cell)).build(options=_try_to_utf8(line).strip())
+        opts, args = self.parse_options(line,'o:')
+        build_options = opts.get('o', '')
+        prg = cl.Program(ctx, _try_to_utf8(cell)).build(options=_try_to_utf8(build_options).strip())
 
         for knl in prg.all_kernels():
             self.shell.user_ns[knl.function_name] = knl