enhance shape inference. allow in complete shape (#94)

nnvm/include/nnvm/tuple.h

@@ -387,6 +387,11 @@ class TShape : public Tuple<index_t> {
   }
 #ifdef MSHADOW_XINLINE
   template<int dim>
+  inline TShape(const mshadow::Shape<dim> &s) {// NOLINT(*)
+    this->assign(s.shape_, s.shape_ + dim);
+  }
+
+  template<int dim>
   inline TShape(mshadow::Shape<dim> &&s) {// NOLINT(*)
     this->assign(s.shape_, s.shape_ + dim);
   }

nnvm/src/pass/infer_shape_type.cc

@@ -155,27 +155,29 @@ Graph InferAttr(Graph &&ret,
     }
   };
 
-  size_t num_unknown = 0;
-  const int kMaxStep = 3;
-  for (int i = 0; i < kMaxStep; ++i) {
+  size_t last_num_unknown;
+  size_t num_unknown = rshape.size();
+  int i = 0;
+  do {
     if (i % 2 == 0) {
       for (uint32_t nid = 0; nid < idx.num_nodes(); ++nid) {
-        infer_step(nid, i + 1 == kMaxStep);
+        infer_step(nid, false);
       }
     } else {
       // backward inference
       for (uint32_t i = idx.num_nodes(); i != 0; --i) {
-        infer_step(i - 1, i + 1 == kMaxStep);
+        infer_step(i - 1, false);
       }
     }
+    last_num_unknown = num_unknown;
     num_unknown = 0;
     for (size_t j = 0; j < idx.num_node_entries(); ++j) {
       if (fis_none(rshape[j])) {
         ++num_unknown;
       }
     }
-    if (num_unknown == 0) break;
-  }
+    ++i;
+  } while (num_unknown > 0 && last_num_unknown > num_unknown);
   // set the shapes
   ret.attrs[attr_name] = std::make_shared<any>(std::move(rshape));
   // number of nodes who knows the shape.
@@ -190,7 +192,7 @@ NNVM_REGISTER_PASS(InferShape)
         std::move(ret), TShape(),
         "FInferShape", "shape_inputs", "shape_attr_key",
         "shape", "shape_num_unknown_nodes",
-        [](const TShape& s) { return s.ndim() == 0; },
+        [](const TShape& s) { return s.ndim() == 0 || s.Size() == 0; },
         nullptr);
   })
 .set_change_graph(false)