Add ImageNet pre-trained weights under pretrained feature flag (#18)

* Add ImageNet pre-trained weights under `pretrained` feature flag

* Remove print comments and fix ResNetConfig private methods

* Fix pretrained weights enum usage and expansion=4 for bigger ResNets

* Fix regex for larger models with more than 10 layer blocks

* Fix error message typo

* Add burn/ndarry to dev-dependencies

resnet-burn/Cargo.toml

@@ -6,17 +6,22 @@ version = "0.1.0"
 edition = "2021"
 
 [features]
-default = ["burn/default"]
-
+default = []
+std = []
+pretrained = ["burn/network", "std", "dep:dirs"]
 
 [dependencies]
 # Note: default-features = false is needed to disable std
-burn = { git = "https://github.com/tracel-ai/burn.git", rev = "75cb5b6d5633c1c6092cf5046419da75e7f74b11", default-features = false }
+burn = { git = "https://github.com/tracel-ai/burn.git", rev = "9a2cbadd41161c8aac142bbcb9c2ceaf5ffd6edd", default-features = false }
+burn-import = { git = "https://github.com/tracel-ai/burn.git", rev = "9a2cbadd41161c8aac142bbcb9c2ceaf5ffd6edd" }
+dirs = { version = "5.0.1", optional = true }
 serde = { version = "1.0.192", default-features = false, features = [
     "derive",
     "alloc",
 ] } # alloc is for no_std, derive is needed
 
 [dev-dependencies]
-burn-import = { git = "https://github.com/tracel-ai/burn.git", rev = "75cb5b6d5633c1c6092cf5046419da75e7f74b11"}
+burn = { git = "https://github.com/tracel-ai/burn.git", rev = "9a2cbadd41161c8aac142bbcb9c2ceaf5ffd6edd", features = [
+    "ndarray",
+] }
 image = { version = "0.24.7", features = ["png", "jpeg"] }

resnet-burn/README.md

@@ -17,17 +17,23 @@ Add this to your `Cargo.toml`:
 resnet-burn = { git = "https://github.com/burn-rs/models", package = "resnet-burn", default-features = false }
 ```
 
+If you want to get the pre-trained ImageNet weights, enable the `pretrained` feature flag.
+
+```toml
+[dependencies]
+resnet-burn = { git = "https://github.com/burn-rs/models", package = "resnet-burn", features = ["pretrained"] }
+```
+
+**Important:** this feature requires `std`.
+
 ### Example Usage
 
-The [inference example](examples/inference.rs) initializes a ResNet-18 with the `NdArray` backend,
-imports the ImageNet pre-trained weights from
-[`torchvision`](https://download.pytorch.org/models/resnet18-f37072fd.pth) and performs inference on
-the provided input image.
+The [inference example](examples/inference.rs) initializes a ResNet-18 from the ImageNet
+[pre-trained weights](https://pytorch.org/vision/stable/models/generated/torchvision.models.resnet18.html#torchvision.models.ResNet18_Weights)
+with the `NdArray` backend and performs inference on the provided input image.
 
-After downloading the
-[pre-trained weights](https://download.pytorch.org/models/resnet18-f37072fd.pth) to the current
-directory, you can run the example with the following command:
+You can run the example with the following command:
 
 ```sh
-cargo run --release --example inference samples/dog.jpg
+cargo run --release --features pretrained --example inference samples/dog.jpg
 ```

resnet-burn/examples/inference.rs

@@ -1,16 +1,13 @@
-use resnet_burn::model::{imagenet, resnet::ResNet};
+use resnet_burn::model::{imagenet, resnet::ResNet, weights};
 
 use burn::{
     backend::NdArray,
     module::Module,
-    record::{FullPrecisionSettings, NamedMpkFileRecorder, Recorder},
+    record::{FullPrecisionSettings, NamedMpkFileRecorder},
     tensor::{backend::Backend, Data, Device, Element, Shape, Tensor},
 };
-use burn_import::pytorch::{LoadArgs, PyTorchFileRecorder};
 
-const TORCH_WEIGHTS: &str = "resnet18-f37072fd.pth";
 const MODEL_PATH: &str = "resnet18-ImageNet1k";
-const NUM_CLASSES: usize = 1000;
 const HEIGHT: usize = 224;
 const WIDTH: usize = 224;
 
@@ -32,22 +29,10 @@ pub fn main() {
 
     // Create ResNet-18
     let device = Default::default();
-    let model: ResNet<NdArray, _> = ResNet::resnet18(NUM_CLASSES, &device);
-
-    // Load weights from torch state_dict
-    let load_args = LoadArgs::new(TORCH_WEIGHTS.into())
-        // Map *.downsample.0.* -> *.downsample.conv.*
-        .with_key_remap("(.+)\\.downsample\\.0\\.(.+)", "$1.downsample.conv.$2")
-        // Map *.downsample.1.* -> *.downsample.bn.*
-        .with_key_remap("(.+)\\.downsample\\.1\\.(.+)", "$1.downsample.bn.$2")
-        // Map layer[i].[j].* -> layer[i].blocks.[j].*
-        .with_key_remap("(layer[1-4])\\.([0-9])\\.(.+)", "$1.blocks.$2.$3");
-    let record = PyTorchFileRecorder::<FullPrecisionSettings>::new()
-        .load(load_args, &device)
-        .map_err(|err| format!("Failed to load weights.\nError: {err}"))
-        .unwrap();
-
-    let model = model.load_record(record);
+    let model: ResNet<NdArray, _> =
+        ResNet::resnet18_pretrained(weights::ResNet18::ImageNet1kV1, &device)
+            .map_err(|err| format!("Failed to load pre-trained weights.\nError: {err}"))
+            .unwrap();
 
     // Save the model to a supported format and load it back
     let recorder = NamedMpkFileRecorder::<FullPrecisionSettings>::new();

resnet-burn/src/lib.rs

@@ -1,3 +1,3 @@
-#![no_std]
+#![cfg_attr(not(feature = "std"), no_std)]
 pub mod model;
 extern crate alloc;