feat(clip): add linear probe evaluation script (#960)

clip/linear_probe.py

@@ -0,0 +1,56 @@
+# Mirror of the Linear Probe Evaluation Script
+# from the official CLIP Repository.
+
+import mlx.core as mx
+import numpy as np
+from image_processor import CLIPImageProcessor
+from mlx.data.datasets import load_cifar10
+from model import CLIPModel
+from PIL import Image
+from sklearn.linear_model import LogisticRegression
+from tqdm import tqdm
+
+
+def get_cifar10(batch_size, root=None):
+    tr = load_cifar10(root=root).batch(batch_size)
+    test = load_cifar10(root=root, train=False).batch(batch_size)
+
+    return tr, test
+
+
+def get_features(model, image_proc, iter):
+    all_features = []
+    all_labels = []
+
+    for batch in tqdm(iter):
+        image, label = batch["image"], batch["label"]
+        x = image_proc([Image.fromarray(im) for im in image])
+        y = mx.array(label)
+
+        image_embeds = model.get_image_features(x)
+        mx.eval(image_embeds)
+
+        all_features.append(image_embeds)
+        all_labels.append(y)
+
+    return mx.concatenate(all_features), mx.concatenate(all_labels)
+
+
+if __name__ == "__main__":
+    model = CLIPModel.from_pretrained("mlx_model")
+    image_proc = CLIPImageProcessor.from_pretrained("mlx_model")
+
+    train_iter, test_iter = get_cifar10(batch_size=256)
+    train_features, train_labels = get_features(model, image_proc, train_iter)
+    test_features, test_labels = get_features(model, image_proc, test_iter)
+
+    # Perform logistic regression
+    # NOTE: The value of C should be determined via a hyperparameter sweep
+    # using a validation split
+    classifier = LogisticRegression(random_state=0, C=0.316, max_iter=1000, verbose=1)
+    classifier.fit(train_features, train_labels)
+
+    # Evaluate using the logistic regression classifier
+    predictions = classifier.predict(test_features)
+    accuracy = (test_labels.squeeze() == predictions).mean().item() * 100
+    print(f"Accuracy = {accuracy:.3f}")

clip/requirements.txt

@@ -1,4 +1,5 @@
 mlx
+mlx-data
 numpy
 transformers
 torch