first draft

src/include/migraphx/check_shapes.hpp

@@ -98,7 +98,7 @@ struct check_shapes
         assert(end != nullptr);
         if(begin != end)
         {
-            if(begin->lens().size() != n)
+            if(begin->max_lens().size() != n)
                 MIGRAPHX_THROW(prefix() + "Only " + std::to_string(n) + "d supported");
         }
         return *this;
@@ -110,7 +110,7 @@ struct check_shapes
         assert(end != nullptr);
         if(begin != end)
         {
-            if(begin->lens().size() > n)
+            if(begin->max_lens().size() > n)
                 MIGRAPHX_THROW(prefix() + "Shape must have at most " + std::to_string(n) +
                                " dimensions");
         }

src/include/migraphx/op/nonmaxsuppression.hpp

@@ -57,25 +57,42 @@ struct nonmaxsuppression
     {
         // requires at least 2 inputs
         check_shapes{{inputs.at(0), inputs.at(1)}, *this}.only_dims(3);
+        // both boxes and scores will be dynamic if one of them is dynamic
+        if(inputs.at(0).dynamic())
+        {
+            // check dynamic dimensions are consistent
+            const auto boxes_dims  = inputs.at(0).dyn_dims();
+            const auto scores_dims = inputs.at(1).dyn_dims();
+            if(boxes_dims.at(1) != scores_dims.at(2))
+            {
+                MIGRAPHX_THROW("NonMaxSuppression: dynamic spatial dimension mismatch between "
+                               "boxes and scores input");
+            }
+            if(boxes_dims.at(0) != inputs.at(1).lens()[0])
+            {
+                MIGRAPHX_THROW("NonMaxSuppression: dynamic number of batches mismatch between "
+                               "boxes and scores input");
+            }
+        }
+        else
+        {
             auto lens = inputs.front().lens();
 
-        // check input shape
             if(lens[1] != inputs.at(1).lens()[2])
             {
                 MIGRAPHX_THROW(
                     "NonMaxSuppression: spatial dimension mismatch between boxes and scores input");
             }
 
-        // check batch sizes
             if(lens[0] != inputs.at(1).lens()[0])
             {
                 MIGRAPHX_THROW(
                     "NonMaxSuppression: number of batches mismatch between boxes and scores input");
             }
-
-        std::vector<int64_t> out_lens(2);
-        out_lens.at(0) = lens.at(1);
-        out_lens.at(1) = 3;
+        }
+        std::vector<shape::dynamic_dimension> out_lens = {};
+        out_lens.push_back({0, inputs.at(0).max_lens().at(1), 0});
+        out_lens.push_back({3, 3, 0});
         return {shape::int64_type, out_lens};
     }
 
@@ -230,10 +247,10 @@ struct nonmaxsuppression
         }
         double iou_threshold     = (args.size() > 3) ? (args.at(3).at<double>()) : 0.0f;
         double score_threshold   = (args.size() > 4) ? (args.at(4).at<double>()) : 0.0f;
+        std::size_t num_selected = 0;
 
         result.visit([&](auto output) {
             visit_all(args[0], args[1])([&](auto boxes, auto scores) {
-                std::fill(output.begin(), output.end(), 0);
                 const auto& lens       = scores.get_shape().lens();
                 const auto num_batches = lens[0];
                 const auto num_classes = lens[1];
@@ -264,10 +281,11 @@ struct nonmaxsuppression
                                  class_idx);
                 });
                 std::copy(selected_indices.begin(), selected_indices.end(), output.begin());
+                num_selected = selected_indices.size();
             });
         });
 
-        return result;
+        return result.reshape({num_selected, 3});
     }
 };