Expose `Solver::Snapshot` to pycaffe

include/caffe/solver.hpp

@@ -60,6 +60,11 @@ class Solver {
   // RestoreSolverStateFrom___ protected methods. You should implement these
   // methods to restore the state from the appropriate snapshot type.
   void Restore(const char* resume_file);
+  // The Solver::Snapshot function implements the basic snapshotting utility
+  // that stores the learned net. You should implement the SnapshotSolverState()
+  // function that produces a SolverState protocol buffer that needs to be
+  // written to disk together with the learned net.
+  void Snapshot();
   virtual ~Solver() {}
   inline const SolverParameter& param() const { return param_; }
   inline shared_ptr<Net<Dtype> > net() { return net_; }
@@ -87,11 +92,6 @@ class Solver {
  protected:
   // Make and apply the update value for the current iteration.
   virtual void ApplyUpdate() = 0;
-  // The Solver::Snapshot function implements the basic snapshotting utility
-  // that stores the learned net. You should implement the SnapshotSolverState()
-  // function that produces a SolverState protocol buffer that needs to be
-  // written to disk together with the learned net.
-  void Snapshot();
   string SnapshotFilename(const string extension);
   string SnapshotToBinaryProto();
   string SnapshotToHDF5();

python/caffe/_caffe.cpp

@@ -286,7 +286,8 @@ BOOST_PYTHON_MODULE(_caffe) {
     .def("solve", static_cast<void (Solver<Dtype>::*)(const char*)>(
           &Solver<Dtype>::Solve), SolveOverloads())
     .def("step", &Solver<Dtype>::Step)
-    .def("restore", &Solver<Dtype>::Restore);
+    .def("restore", &Solver<Dtype>::Restore)
+    .def("snapshot", &Solver<Dtype>::Snapshot);
 
   bp::class_<SGDSolver<Dtype>, bp::bases<Solver<Dtype> >,
     shared_ptr<SGDSolver<Dtype> >, boost::noncopyable>(

python/caffe/test/test_solver.py

@@ -16,7 +16,8 @@ def setUp(self):
         f.write("""net: '""" + net_f + """'
         test_iter: 10 test_interval: 10 base_lr: 0.01 momentum: 0.9
         weight_decay: 0.0005 lr_policy: 'inv' gamma: 0.0001 power: 0.75
-        display: 100 max_iter: 100 snapshot_after_train: false""")
+        display: 100 max_iter: 100 snapshot_after_train: false
+        snapshot_prefix: "model" """)
         f.close()
         self.solver = caffe.SGDSolver(f.name)
         # also make sure get_solver runs
@@ -51,3 +52,11 @@ def test_net_memory(self):
                     total += p.data.sum() + p.diff.sum()
             for bl in six.itervalues(net.blobs):
                 total += bl.data.sum() + bl.diff.sum()
+
+    def test_snapshot(self):
+        self.solver.snapshot()
+        # Check that these files exist and then remove them
+        files = ['model_iter_0.caffemodel', 'model_iter_0.solverstate']
+        for fn in files:
+            assert os.path.isfile(fn)
+            os.remove(fn)