Enhance: Quant Tensor Test

tests/brevitas/quant_tensor/test_quant_tensor.py

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+# Copyright (C) 2024, Advanced Micro Devices, Inc. All rights reserved.
+# SPDX-License-Identifier: BSD-3-Clause
+from enum import Enum
+
+import pytest
+import torch
+
+from brevitas.inject.enum import QuantType
+from brevitas.nn import QuantIdentity
+from brevitas.quant_tensor import QuantTensor
+
+
+class Operator(Enum):
+    ADD = 0
+    SUBTRACT = 1
+    DIVIDE = 2
+    MULTIPLY = 3
+    MATMUL = 4
+
+
+def to_quant_tensor(input: torch.Tensor) -> QuantTensor:
+    mod = QuantIdentity(bit_width=8, return_quant_tensor=True)
+    return mod(input)
+
+
+def qdq(normal_tensor, quant_tensor):
+    return (
+        torch.round(normal_tensor / quant_tensor.scale + quant_tensor.zero_point) -
+        quant_tensor.zero_point) * quant_tensor.scale
+
+
+def test_quant_tensor_init():
+    x = torch.randn(4, 4)
+    quant_tensor = to_quant_tensor(x)
+    normal_tensor = torch.Tensor(x)
+    assert torch.allclose(qdq(normal_tensor, quant_tensor), quant_tensor, rtol=0.01)
+
+
+@pytest.mark.parametrize(
+    'op', [Operator.ADD, Operator.SUBTRACT, Operator.DIVIDE, Operator.MULTIPLY, Operator.MATMUL])
+def test_quant_tensor_operators(op):
+    x = torch.randn(4, 4)
+
+    a = torch.Tensor(x)
+    b = torch.Tensor(x)
+
+    qa = to_quant_tensor(a)
+    qb = to_quant_tensor(b)
+
+    # to factor in quantisation error
+    e_a = a - qa
+    e_b = b - qb
+
+    if op == Operator.ADD:
+        quant = qa + qb
+        normal = (a - e_a) + (b - e_b)
+    elif op == Operator.SUBTRACT:
+        quant = qa - qb
+        normal = (a - e_a) - (b - e_b)
+    elif op == Operator.DIVIDE:
+        quant = qa / qb
+        normal = (a - e_a) / (b - e_b)
+    elif op == Operator.MULTIPLY:
+        quant = qa * qb
+        normal = (a - e_a) * (b - e_b)
+    elif op == Operator.MATMUL:
+        # @ matmul operator not implemented for QuantTensor
+        quant = torch.matmul(qa, qb)
+        normal = (a - e_a) @ (b - e_b)
+    else:
+        # unrecognised operator
+        assert False
+
+    # tolerance set to a high value as there is considerable loss of precision
+    assert torch.allclose(normal, quant)
+
+
+def test_quant_tensor_div_by_zero():
+    a = to_quant_tensor(torch.ones(4, 4))
+    b = to_quant_tensor(torch.zeros(4, 4))
+    assert torch.isinf(a / b).all().item()
+
+
+def test_quant_tensor_div_by_fraction():
+    a = to_quant_tensor(torch.ones(4, 4))
+    b = to_quant_tensor(torch.ones(4, 4) * 0.5)
+    assert torch.allclose(a / b, torch.ones(4, 4) * 2, atol=0.1)
+
+
+# TODO: need to deal with quant metadata
+def test_quant_tensor_transpose():
+    x = torch.ones(4, 4).tril()
+    a = x.clone()
+    b = to_quant_tensor(x)
+    assert torch.allclose(a.transpose(0, 1), b.transpose(0, 1), atol=0.01)
+
+
+# TODO: need to deal with quant metadata
+def test_quant_tensor_view():
+    x = torch.ones(4, 4)
+    a = to_quant_tensor(x)
+    b = torch.Tensor(x)
+
+    assert torch.allclose(a.view(-1), b.view(-1), atol=0.01)
+    assert torch.allclose(a.view(2, -1), b.view(2, -1), atol=0.01)
+    assert torch.allclose(a.view(16, -1), b.view(16, -1), atol=0.01)
+    assert torch.allclose(a.view(8, 2), b.view(8, 2), atol=0.01)