remove TensorFlow rounding mode HALF_AWAY_FROM_ZERO (#2047)

src/ngraph/op/quantize.hpp

@@ -37,7 +37,6 @@ namespace ngraph
                 // 2.5 -> 3
                 // -3.5 -> -4
                 ROUND_NEAREST_TOWARD_INFINITY,
-                HALF_AWAY_FROM_ZERO, // TF mode for backward compatability
 
                 // round to nearest integer
                 // in case of two equidistant integers round toward zero e.g.

src/ngraph/pass/constant_folding.cpp

@@ -567,7 +567,7 @@ void ngraph::pass::ConstantFolding::construct_constant_quantize()
         make_shared<pattern::op::Label>(element::f32, Shape{2}, pattern::has_class<op::Constant>());
     auto q_scale = op::Constant::create(element::f32, Shape{}, {1});
     auto q_offset = op::Constant::create(element::i8, Shape{}, {0});
-    auto mode = op::Quantize::RoundMode::HALF_AWAY_FROM_ZERO;
+    auto mode = op::Quantize::RoundMode::ROUND_NEAREST_TOWARD_INFINITY;
     auto quant_op =
         make_shared<op::Quantize>(constant_label, q_scale, q_offset, element::i8, AxisSet{}, mode);
     auto quant = make_shared<pattern::op::Label>(quant_op, nullptr, NodeVector{quant_op});
@@ -592,11 +592,6 @@ void ngraph::pass::ConstantFolding::construct_constant_quantize()
             return false;
         }
 
-        if (quantize_op->get_round_mode() != op::Quantize::RoundMode::HALF_AWAY_FROM_ZERO)
-        {
-            return false;
-        }
-
         if (type == element::u8)
         {
             replace_node(

src/ngraph/runtime/reference/quantize.hpp

@@ -47,8 +47,7 @@ namespace ngraph
                                   scale[scale_offset_transform.index(scale_offset_coord)];
 
                     // round
-                    if (round_mode == op::Quantize::RoundMode::ROUND_NEAREST_TOWARD_INFINITY ||
-                        round_mode == op::Quantize::RoundMode::HALF_AWAY_FROM_ZERO)
+                    if (round_mode == op::Quantize::RoundMode::ROUND_NEAREST_TOWARD_INFINITY)
                     {
                         auto abs_qvalue = std::fabs(qvalue);
                         auto abs_qvalue_toward_inf = std::floor(abs_qvalue + 0.5);

test/constant_folding.cpp

@@ -265,7 +265,7 @@ TEST(constant_folding, const_quantize)
     auto constant = op::Constant::create(element::f32, input_shape, values_in);
     auto scale = op::Constant::create(element::f32, scale_offset_shape, {2});
     auto offset = op::Constant::create(quant_type, scale_offset_shape, {1});
-    auto mode = op::Quantize::RoundMode::HALF_AWAY_FROM_ZERO;
+    auto mode = op::Quantize::RoundMode::ROUND_NEAREST_TOWARD_INFINITY;
     auto quantize =
         make_shared<op::Quantize>(constant, scale, offset, output_type, quantization_axes, mode);
     auto f = make_shared<Function>(quantize, op::ParameterVector{});