Port BLIP-2 entire model to OSS folder (#487)

Summary:
Pull Request resolved: #487

as title

Reviewed By: ebsmothers

Differential Revision: D50236403

fbshipit-source-id: 06fab6bb9324d0425679394f85935c6cd4ca373f

tests/models/blip2/__init__.py

@@ -0,0 +1,5 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.

tests/models/blip2/test_blip2.py

@@ -0,0 +1,137 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+
+
+import pytest
+import torch
+import torch.nn as nn
+from tests.test_utils import assert_expected, init_weights_with_constant
+from torchmultimodal.models.blip2.blip2 import BLIP2
+from torchmultimodal.models.blip2.qformer_model import QformerForCLM
+from torchmultimodal.modules.encoders.vision_transformer import VisionTransformer
+from torchmultimodal.modules.layers.patch_embedding import PatchEmbeddings
+from torchmultimodal.modules.layers.transformer import TransformerEncoder
+
+
+@pytest.fixture
+def dim_q():
+    return 4
+
+
+@pytest.fixture
+def dim_kv():
+    return 2
+
+
+@pytest.fixture
+def dim_feedforward():
+    return 6
+
+
+@pytest.fixture
+def num_hidden_layers():
+    return 2
+
+
+@pytest.fixture
+def num_heads():
+    return 2
+
+
+@pytest.fixture
+def vocab_size():
+    return 20
+
+
+@pytest.fixture
+def qformer_model_for_clm(
+    dim_q,
+    dim_kv,
+    dim_feedforward,
+    num_hidden_layers,
+    num_heads,
+    vocab_size,
+):
+    qformer_for_clm = QformerForCLM(
+        dim_q=dim_q,
+        dim_kv=dim_kv,
+        dim_feedforward=dim_feedforward,
+        num_heads=num_heads,
+        attn_dropout=0.0,
+        dropout=0.0,
+        num_hidden_layers=num_hidden_layers,
+        max_position_embeddings=512,
+        vocab_size=vocab_size,
+    )
+    return qformer_for_clm
+
+
+@pytest.fixture
+def vit():
+    embedding = PatchEmbeddings(image_size=2, patch_size=1, hidden_size=2)
+    encoder = TransformerEncoder(
+        n_layer=1,
+        d_model=2,
+        n_head=1,
+        dim_feedforward=1,
+        activation=nn.GELU,
+        norm_first=True,
+        final_layer_norm_eps=1e-5,
+    )
+    image_encoder = VisionTransformer(
+        embeddings=embedding,
+        encoder=encoder,
+    )
+    init_weights_with_constant(image_encoder)
+    image_encoder.eval()
+    return image_encoder
+
+
+@pytest.fixture
+def blip2(dim_q, dim_kv, qformer_model_for_clm, vit):
+    blip2 = BLIP2(
+        dim_q=dim_q,
+        image_encoder_embedding_dim=dim_kv,
+        qformer=qformer_model_for_clm,
+        vision_encoder=vit,
+        embedding_dim=4,
+        decoder_bos_token_id=19,
+    )
+    init_weights_with_constant(blip2)
+    blip2.eval()
+    return blip2
+
+
+@pytest.fixture
+def attn_mask():
+    return torch.Tensor([[1.0, 0.0, 1.0, 1.0], [0.0, 1.0, 1.0, 1.0]])
+
+
+class TestBLIP2:
+    def test_blip2(self, blip2, attn_mask):
+        image = torch.ones(2, 3, 2, 2)
+        input_ids = torch.ones(2, 4).long()
+        output = blip2(image, input_ids, attn_mask)
+        assert_expected(
+            output.image_features, torch.ones([2, 32, 4]) * 0.5, rtol=0, atol=1e-4
+        )
+        assert_expected(
+            output.text_features, torch.ones([2, 4]) * 0.5, rtol=0, atol=1e-4
+        )
+        assert_expected(
+            output.image_embeddings, torch.ones([2, 5, 2]), rtol=0, atol=1e-4
+        )
+        assert_expected(
+            output.prediction_scores, torch.ones([2, 4, 20]) * 5, rtol=0, atol=1e-4
+        )
+
+    def test_blip2_scripting(self, blip2, attn_mask):
+        image = torch.ones(2, 3, 2, 2)
+        input_ids = torch.ones(2, 4).long()
+        scripted_model = torch.jit.script(blip2)
+        actual = scripted_model(image, input_ids, attn_mask)
+        expected = blip2(image, input_ids, attn_mask)
+        assert_expected(actual, expected)