caffe: depend on opencv3

openblas is used since it's propagated from OpenCV and ATLAS compiled without
architecture-specific optimizations is generally slower than OpenBLAS as I
heard.

pkgs/applications/science/math/caffe/default.nix

@@ -7,11 +7,11 @@
 , hdf5-cpp
 , leveldb
 , lmdb
-, opencv
+, opencv3
 , protobuf
 , snappy
-, atlas
 , doxygen
+, openblas
 , cudaSupport ? true, cudatoolkit
 , cudnnSupport ? false, cudnn ? null
 , pythonSupport ? false, python ? null, numpy ? null
@@ -35,12 +35,15 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ cmake doxygen ];
 
-  cmakeFlags = [
-    "-DCUDA_ARCH_NAME=All"
-    (if pythonSupport then "-Dpython_version=${python.version}" else "-DBUILD_python=OFF")
-  ] ++ lib.optional (!cudaSupport) "-DCPU_ONLY=ON";
+  cmakeFlags =
+    [ (if pythonSupport then "-Dpython_version=${python.version}" else "-DBUILD_python=OFF")
+      "-DBLAS=open"
+    ] ++ (if cudaSupport then [
+           "-DCUDA_ARCH_NAME=All"
+           "-DCUDA_HOST_COMPILER=${cudatoolkit.cc}/bin/cc"
+         ] else [ "-DCPU_ONLY=ON" ]);
 
-  buildInputs = [ boost google-gflags glog protobuf hdf5-cpp lmdb leveldb snappy opencv atlas ]
+  buildInputs = [ boost google-gflags glog protobuf hdf5-cpp lmdb leveldb snappy opencv3 openblas ]
                 ++ lib.optional cudaSupport cudatoolkit
                 ++ lib.optional cudnnSupport cudnn
                 ++ lib.optionals pythonSupport [ python numpy ];

pkgs/top-level/all-packages.nix

@@ -19737,6 +19737,10 @@ with pkgs;
   caffe = callPackage ../applications/science/math/caffe rec {
     cudaSupport = config.caffe.cudaSupport or config.cudaSupport or false;
     cudnnSupport = cudaSupport;
+    # Used only for image loading.
+    opencv3 = self.opencv3.override {
+      enableCuda = false;
+    };
   };
 
   caffe2 = callPackage ../development/libraries/science/math/caffe2 {