From 06532a823fb5ccf6847480a2b2dd811dce836ba9 Mon Sep 17 00:00:00 2001
From: "Michael F. Herbst" <info@michael-herbst.com>
Date: Sat, 9 Nov 2019 14:11:00 +0100
Subject: [PATCH] Detect and honour an MKL numpy when building adccore (#23)

---
 docs/developers.rst  | 17 +++++++++++++++++
 extension/AdcCore.py | 27 ++++++++++++++++++++++++++-
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/docs/developers.rst b/docs/developers.rst
index 080f7be0..14c8c983 100644
--- a/docs/developers.rst
+++ b/docs/developers.rst
@@ -139,6 +139,23 @@ This is done to avoid automatically overwriting some development changes
 you might have made inside ``adccore``.
 
 
+Building adccore with MKL support
+---------------------------------
+
+If you have full source code access
+and you are able to follow the :ref:`adccore-sources`,
+the `Intel Math Kernel Library (R) <https://software.intel.com/en-us/mkl>`_
+can also be integrated into adccore and thus adcc.
+In fact this integration happens automatically during the build
+process of adccore, given that a numpy linked to the MKL was
+detected. For this reason proceed as follows:
+
+1. Load the MKL modules or activate the MKL in your shell as you usally do.
+2. Build and install numpy with linkage to this MKL,
+   e.g. `Build numpy from source <https://docs.scipy.org/doc/numpy/user/building.html>`_.
+3. Build adcc and adccore as described in :ref:`adccore-sources`.
+
+
 ``setup.py`` reference
 ----------------------
 The ``setup.py`` script of adcc is a largely a typical setuptools script,
diff --git a/extension/AdcCore.py b/extension/AdcCore.py
index 97de88ea..cfe7dc52 100644
--- a/extension/AdcCore.py
+++ b/extension/AdcCore.py
@@ -41,6 +41,27 @@ def get_platform():
     return result
 
 
+def has_mkl_numpy():
+    """Has numpy been installed and linked against MKL"""
+    try:
+        import numpy.__config__
+
+        if not hasattr(numpy.__config__, "blas_mkl_info"):
+            return False
+        return any("mkl" in lib
+                   for lib in numpy.__config__.blas_mkl_info.get("libraries", {}))
+    except ImportError as e:
+        if "mkl" in str(e):
+            # numpy seems to be installed and linked against MKL, but mkl was not found.
+            raise ImportError("Trying to import numpy for MKL check, but obtained an "
+                              "import error indicating a missing MKL dependency. "
+                              "Did you load the MKL modules properly?") from e
+
+        # This indicates a missing numpy or a big error in numpy. It's best to assume
+        # MKL is not there and (potentially) install the non-mkl version from pypi
+        return False
+
+
 def request_urllib(url, filename):
     """Download a file from the net using requests, displaying
     a nice progress bar along the way"""
@@ -123,8 +144,12 @@ def build(self):
 
         import build_adccore
 
+        features = []
+        if has_mkl_numpy():
+            features += ["mkl"]
+
         build_dir = join(self.source_dir, "build")
-        build_adccore.build_install(build_dir, self.install_dir)
+        build_adccore.build_install(build_dir, self.install_dir, features=features)
 
     def build_documentation(self):
         """Build adccore documentation. Only valid if has_source is true"""