Add pystencils.opencl.autoinit

conftest.py

 import os
-import pytest
-import tempfile
 import runpy
 import sys
 import warnings
+import tempfile
+
+import nbformat
+import pytest
+from nbconvert import PythonExporter
+
+from pystencils.boundaries.createindexlistcython import *  # NOQA
 # Trigger config file reading / creation once - to avoid race conditions when multiple instances are creating it
 # at the same time
 from pystencils.cpu import cpujit
@@ -15,7 +20,6 @@ try:
     pyximport.install(language_level=3)
 except ImportError:
     pass
-from pystencils.boundaries.createindexlistcython import *  # NOQA
 
 
 SCRIPT_FOLDER = os.path.dirname(os.path.realpath(__file__))
@@ -29,7 +33,8 @@ def add_path_to_ignore(path):
     collect_ignore += [os.path.join(SCRIPT_FOLDER, path, f) for f in os.listdir(os.path.join(SCRIPT_FOLDER, path))]
 
 
-collect_ignore = [os.path.join(SCRIPT_FOLDER, "doc", "conf.py")]
+collect_ignore = [os.path.join(SCRIPT_FOLDER, "doc", "conf.py"),
+        os.path.join(SCRIPT_FOLDER, "pystencils", "opencl", "opencl.autoinit")]
 add_path_to_ignore('pystencils_tests/benchmark')
 add_path_to_ignore('_local_tmp')
 
@@ -78,8 +83,6 @@ for root, sub_dirs, files in os.walk('.'):
             collect_ignore.append(f)
 
 
-import nbformat
-from nbconvert import PythonExporter
 
 
 class IPythonMockup:

pystencils/datahandling/pyopencl.py

@@ -14,7 +14,8 @@ class PyOpenClArrayHandler:
         if not queue:
             from pystencils.opencl.opencljit import get_global_cl_queue
             queue = get_global_cl_queue()
-        assert queue, "OpenCL queue missing"
+        assert queue, "OpenCL queue missing!\n" \
+            "Use `import pystencils.opencl.autoinit` if you want it to be automatically created"
         self.queue = queue
 
     def zeros(self, shape, dtype=np.float64, order='C'):

pystencils/opencl/__init__.py

+"""
+
+"""
+
+from pystencils.opencl.opencljit import (
+    clear_global_ctx, init_globally, init_globally_with_context, make_python_function)
+
+__all__ = ['init_globally', 'init_globally_with_context', 'clear_global_ctx', 'make_python_function']

pystencils/opencl/autoinit.py

+"""
+Automatically initializes OpenCL context using any device.
+
+Use `pystencils.opencl.{init_globally_with_context,init_globally}` if you want to use a specific device.
+"""
+
+from pystencils.opencl import *  # noqa
+from pystencils.opencl.opencljit import *  # noqa
+from pystencils.opencl.opencljit import init_globally
+
+init_globally()

pystencils/opencl/opencljit.py

@@ -65,8 +65,10 @@ def make_python_function(kernel_function_node, opencl_queue, opencl_ctx, argumen
     if not opencl_queue:
         opencl_queue = _global_cl_queue
 
-    assert opencl_ctx, "No valid OpenCL context"
-    assert opencl_queue, "No valid OpenCL queue"
+    assert opencl_ctx, "No valid OpenCL context!\n" \
+        "Use `import pystencils.opencl.autoinit` if you want it to be automatically created"
+    assert opencl_queue, "No valid OpenCL queue!\n" \
+        "Use `import pystencils.opencl.autoinit` if you want it to be automatically created"
 
     if argument_dict is None:
         argument_dict = {}

pystencils_tests/test_opencl.py

 import numpy as np
 import pytest
+import sympy as sp
 
 import pystencils
-import sympy as sp
 from pystencils.backends.cuda_backend import CudaBackend
 from pystencils.backends.opencl_backend import OpenClBackend
-from pystencils.opencl.opencljit import make_python_function, init_globally, get_global_cl_queue
+from pystencils.opencl.opencljit import get_global_cl_queue, init_globally, make_python_function
 
 try:
     import pyopencl as cl
@@ -235,9 +235,9 @@ def test_without_cuda():
     opencl_kernel(x=x, y=y, z=z)
 
 
-
 @pytest.mark.skipif(not HAS_OPENCL, reason="Test requires pyopencl")
 def test_kernel_creation():
+    global pystencils
     z, y, x = pystencils.fields("z, y, x: [20,30]")
 
     assignments = pystencils.AssignmentCollection({
@@ -246,8 +246,9 @@ def test_kernel_creation():
 
     print(assignments)
 
+    pystencils.opencl.clear_global_ctx()
 
-    init_globally()
+    import pystencils.opencl.autoinit
     ast = pystencils.create_kernel(assignments, target='opencl')
 
     print(ast.backend)
@@ -270,4 +271,3 @@ def test_kernel_creation():
 
     assert opencl_kernel is not None
     opencl_kernel(x=x, y=y, z=z)
-