Internal dev README (potentially user-facing README)

README.md

@@ -83,37 +83,262 @@ pip install sparsezoo
 
 ## Quick Tour
 
-### Python APIs
+The SparseZoo Python API enables you to search and download sparsified models. Code examples are given below.
+We encourage the users to load SparseZoo models by copying a stub directly from a [model page]((https://sparsezoo.neuralmagic.com/)).
 
-The Python APIs respect this format enabling you to search and download models. Some code examples are given below.
-The [SparseZoo UI](https://sparsezoo.neuralmagic.com/) also enables users to load models by copying
-a stub directly from a model page.
+### Introduction to Model Class Object
 
+The `Model` is a fundamental object that serves as a main interface with the SparseZoo library. 
+It represents a SparseZoo model, together with all its directories and files.
 
-#### Loading from a Stub
+#### Creating a Model Class Object From SparseZoo Stub
+```python
+from sparsezoo import Model
+
+stub = "zoo:cv/classification/resnet_v1-50/pytorch/sparseml/imagenet/pruned95_quant-none"
+
+model = Model(stub)
+print(str(model))
+
+>> Model(stub=zoo:cv/classification/resnet_v1-50/pytorch/sparseml/imagenet/pruned95_quant-none)
+```
 
+#### Creating a Model Class Object From Local Model Directory
 ```python
 from sparsezoo import Model
 
-# copied from https://sparsezoo.neuralmagic.com/
-stub = "zoo:cv/classification/resnet_v1-50/pytorch/sparseml/imagenet/pruned90_quant-none"
+directory = ".../.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0"
+
+model = Model(directory)
+print(str(model))
+
+>> Model(directory=.../.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0)
+```
+
+#### Manually Specifying the Model Download Path
+
+Unless specified otherwise, the model created from the SparseZoo stub is saved to the local sparsezoo cache directory. 
+This can be overridden by passing the optional `download_path` argument to the constructor:
+
+```python
+from sparsezoo import Model
+
+stub = "zoo:cv/classification/resnet_v1-50/pytorch/sparseml/imagenet/pruned95_quant-none"
+download_directory = "./model_download_directory"
+
+model = Model(stub, download_path = download_directory)
+```
+#### Downloading the Model Files
+Once the model is initialized from a stub, it may be downloaded either by calling the `download()` method or by invoking a `path` property. Both pathways are universal for all the files in SparseZoo. Invoking the `path` property will always trigger file download unless the file has already been downloaded.
+
+```python
+# method 1
+model.download() 
+
+# method 2 
+model_path = model.path
+```
+
+#### Inspecting the Contents of the SparseZoo Model
+
+We call the `available_files` method to inspect which files are present in the SparseZoo model. Then, we select a file by calling the appropriate attribute:
+
+```python
+model.available_files
+
+>> {'training': Directory(name=training), 
+>> 'deployment': Directory(name=deployment), 
+>> 'sample_inputs': Directory(name=sample_inputs.tar.gz), 
+>> 'sample_outputs': {'framework': Directory(name=sample_outputs.tar.gz)}, 
+>> 'sample_labels': Directory(name=sample_labels.tar.gz), 
+>> 'model_card': File(name=model.md), 
+>> 'recipes': Directory(name=recipe), 
+>> 'onnx_model': File(name=model.onnx)}
+```
+Then, we might take a closer look at the contents of the SparseZoo model:
+```python
+model_card = model.model_card
+print(model_card)
+
+>> File(name=model.md)
+```
+```python
+model_card_path = model.model_card.path
+print(model_card_path)
+
+>> .../.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0/model.md
+```
+
+
+### Model, Directory, and File
+
+In general, every file in the SparseZoo model shares a set of attributes: `name`, `path`, `URL`, and `parent`:
+- `name` serves as an identifier of the file/directory
+- `path` points to the location of the file/directory 
+- `URL` specifies the server address of the file/directory in question
+- `parent` points to the location of the parent directory of the file/directory in question
+
+A directory is a unique type of file that contains other files. For that reason, it has an additional `files` attribute.
+
+```python
+print(model.onnx_model)
+
+>> File(name=model.onnx)
+
+print(f"File name: {model.onnx_model.name}\n"
+      f"File path: {model.onnx_model.path}\n"
+      f"File URL: {model.onnx_model.url}\n"
+      f"Parent directory: {model.onnx_model.parent_directory}")
+
+>> File name: model.onnx
+>> File path: .../.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0/model.onnx
+>> File URL: https://models.neuralmagic.com/cv-classification/...
+>> Parent directory: .../.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0
+```
+
+```python
+print(model.recipes)
+
+>> Directory(name=recipe)
+
+print(f"File name: {model.recipes.name}\n"
+      f"Contains: {[file.name for file in model.recipes.files]}\n"
+      f"File path: {model.recipes.path}\n"
+      f"File URL: {model.recipes.url}\n"
+      f"Parent directory: {model.recipes.parent_directory}")
+
+>> File name: recipe
+>> Contains: ['recipe_original.md', 'recipe_transfer-classification.md']
+>> File path: /home/user/.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0/recipe
+>> File URL: None
+>> Parent directory: /home/user/.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0
+```
+
+### Selecting Checkpoint-Specific Data
+
+A SparseZoo model may contain several checkpoints. The model may contain a checkpoint that had been saved before the model was quantized - that checkpoint would be used for transfer learning. Another checkpoint might have been saved after the quantization step - that one is usually directly used for inference.
+
+The recipes may also vary depending on the use case. We may want to access a recipe that was used to sparsify the dense model (`recipe_original`) or the one that enables us to sparse transfer learn from the already sparsified model (`recipe_transfer`). 
+
+There are two ways to access those specific files.
+
+#### Accessing Recipes (Through Python API)
+```python
+available_recipes = model.recipes.available
+print(available_recipes)
+
+>> ['original', 'transfer-classification']
+
+transfer_recipe = model.recipes["transfer-classification"]
+print(transfer_recipe)
+
+>> File(name=recipe_transfer-classification.md)
+
+original_recipe = model.recipes.default # recipe defaults to `original`
+original_recipe_path = original_recipe.path # downloads the recipe and returns its path
+print(original_recipe_path)
+
+>> .../.cache/sparsezoo/eb977dae-2454-471b-9870-4cf38074acf0/recipe/recipe_original.md
+```
+
+#### Accessing Checkpoints (Through Python API)
+In general, we are expecting the following checkpoints to be included in the model: 
+
+- `checkpoint_prepruning`
+- `checkpoint_postpruning`
+- `checkpoint_preqat`
+- `checkpoint_postqat` 
+
+The checkpoint that the model defaults to is the `preqat` state (just before the quantization step).
+
+```python
+from sparsezoo import Model
+
+stub = "zoo:nlp/question_answering/bert-base/pytorch/huggingface/squad/pruned_quant_3layers-aggressive_84"
+
 model = Model(stub)
-print(model)
+available_checkpoints = model.training.available
+print(available_checkpoints)
+
+>> ['preqat']
+
+preqat_checkpoint = model.training.default # recipe defaults to `preqat`
+preqat_checkpoint_path = preqat_checkpoint.path # downloads the checkpoint and returns its path
+print(preqat_checkpoint_path)
+
+>> .../.cache/sparsezoo/0857c6f2-13c1-43c9-8db8-8f89a548dccd/training
+
+[print(file.name) for file in preqat_checkpoint.files]
+
+>> vocab.txt
+>> special_tokens_map.json
+>> pytorch_model.bin
+>> config.json
+>> training_args.bin
+>> tokenizer_config.json
+>> trainer_state.json
+>> tokenizer.json
 ```
 
-#### Searching the Zoo
+
+#### Accessing Recipes (Through Stub String Arguments)
+
+You can also directly request a specific recipe/checkpoint type by appending the appropriate URL query arguments to the stub:
+```python
+from sparsezoo import Model
+
+stub = "zoo:cv/classification/resnet_v1-50/pytorch/sparseml/imagenet/pruned95_quant-none?recipe=transfer"
+
+model = Model(stub)
+
+# Inspect which files are present.
+# Note that the available recipes are restricted
+# according to the specified URL query arguments
+print(model.recipes.available)
+
+>> ['transfer-classification']
+
+transfer_recipe = model.recipes.default # Now the recipes default to the one selected by the stub string arguments
+print(transfer_recipe)
+
+>> File(name=recipe_transfer-classification.md)
+```
+
+### Accessing Sample Data
+
+The user may easily request a sample batch of data that represents the inputs and outputs of the model.
+
+```python
+sample_data = model.sample_batch(batch_size = 10)
+
+print(sample_data['sample_inputs'][0].shape)
+>> (10, 3, 224, 224) # (batch_size, num_channels, image_dim, image_dim)
+
+print(sample_data['sample_outputs'][0].shape)
+>> (10, 1000) # (batch_size, num_classes)
+```
+
+### Model Search
+The function `search_models` enables the user to quickly filter the contents of SparseZoo repository to find the stubs of interest:
 
 ```python
 from sparsezoo import search_models
 
-models = search_models(
-    domain="cv",
-    sub_domain="classification",
-    return_stubs=True,
-)
-print(models)
+args = {
+    "domain": "cv",
+    "sub_domain": "segmentation",
+    "architecture": "yolact",
+}
+
+models = search_models(**args)
+[print(model) for model in models]
+
+>> Model(stub=zoo:cv/segmentation/yolact-darknet53/pytorch/dbolya/coco/pruned82_quant-none)
+>> Model(stub=zoo:cv/segmentation/yolact-darknet53/pytorch/dbolya/coco/pruned90-none)
+>> Model(stub=zoo:cv/segmentation/yolact-darknet53/pytorch/dbolya/coco/base-none)
 ```
 
+
 ### Environmental Variables
 
 Users can specify the directory where models (temporarily during download) and its required credentials will be saved in your working machine.