MLBEDSW-2679: Tensor quant comparison is incorrect

 - Fixed bug with the supported operator check rejecting operators based
   upon an incorrect comparison of the tensor quantisations

Signed-off-by: Tim Hall <tim.hall@arm.com>
Change-Id: Ibd0eb50077465d2c515c6ee10394d9b43cdf730c

2 files changed, 14 insertions, 17 deletions

diff --git a/ethosu/vela/supported_operators.py b/ethosu/vela/supported_operators.py
index e6aaca31..65588bf4 100644
--- a/ethosu/vela/supported_operators.py
+++ b/ethosu/vela/supported_operators.py
@@ -115,7 +115,7 @@ class SupportedOperators:
             {op: self.check_memory_only_restrictions for op in self.memory_only_ops}
         )
         self.supported_operator_restrictions.update(
-            {op: self.check_quantization_restrictions for op in self.binary_elem_wise_min_max_ops}
+            {op: self.check_quantization_restrictions_binary_elem_wise for op in self.binary_elem_wise_min_max_ops}
         )
         self.supported_operator_restrictions.update({op: self.check_activation_ops for op in self.activation_ops})
 
@@ -364,16 +364,20 @@ class SupportedOperators:
                 return False
         return True
 
-    def check_quantization_restrictions(self, op):
+    def check_quantization_restrictions_binary_elem_wise(self, op):
         # makes sure IFM1, IFM2 and OFM quantization are equal for binary ops
+        assert len(op.inputs) >= 2 and len(op.outputs) == 1
+
         if (
-            len(op.inputs) == 2
-            and not op.inputs[0].quantization == op.inputs[1].quantization == op.outputs[0].quantization
+            op.inputs[0].quantization is None
+            or not op.inputs[0].quantization.is_scaling_equal(op.inputs[1].quantization)
+            or not op.inputs[0].quantization.is_scaling_equal(op.outputs[0].quantization)
         ):
             print(
                 "Warning: Input/output tensors with different quantization is unsupported for the", op.type, "operator"
             )
             return False
+
         return True
 
     def check_activation_ops(self, op):
diff --git a/ethosu/vela/tensor.py b/ethosu/vela/tensor.py
index 66bed59d..5fdea979 100644
--- a/ethosu/vela/tensor.py
+++ b/ethosu/vela/tensor.py
@@ -184,19 +184,6 @@ class QuantizationParameters:
 
     __repr__ = __str__
 
-    def __eq__(self, other):
-        if other is None:
-            return False
-        if not isinstance(other, QuantizationParameters):
-            return False
-
-        pairs = ((getattr(self, s), getattr(other, s)) for s in QuantizationParameters.__slots__)
-
-        return all(np.array_equal(a, b) for a, b in pairs)
-
-    def __ne__(self, other):
-        return not self == other
-
     def clone(self):
         res = QuantizationParameters()
         res.min = self.min
@@ -232,6 +219,12 @@ class QuantizationParameters:
 
         return res
 
+    def is_scaling_equal(self, other):
+        if other is None or not isinstance(other, QuantizationParameters):
+            return False
+
+        return self.scale_f32 == other.scale_f32 and self.zero_point == other.zero_point
+
 
 def create_const_tensor(name, shape, dtype, values, value_dtype=None, purpose=TensorPurpose.Unknown, quantization=None):
     # Tensor