Stable diffusion: retrieve the model files from the HF hub. (#414)

* Retrieve the model files from the HF hub in the stable diffusion example.

* Add to the readme.

candle-examples/examples/stable-diffusion/main.rs

@@ -45,21 +45,21 @@ struct Args {
     #[arg(long)]
     width: Option<usize>,
 
-    /// The UNet weight file, in .ot or .safetensors format.
+    /// The UNet weight file, in .safetensors format.
     #[arg(long, value_name = "FILE")]
     unet_weights: Option<String>,
 
-    /// The CLIP weight file, in .ot or .safetensors format.
+    /// The CLIP weight file, in .safetensors format.
     #[arg(long, value_name = "FILE")]
     clip_weights: Option<String>,
 
-    /// The VAE weight file, in .ot or .safetensors format.
+    /// The VAE weight file, in .safetensors format.
     #[arg(long, value_name = "FILE")]
     vae_weights: Option<String>,
 
     #[arg(long, value_name = "FILE")]
     /// The file specifying the tokenizer to used for tokenization.
-    tokenizer: String,
+    tokenizer: Option<String>,
 
     /// The size of the sliced attention or 0 for automatic slicing (disabled by default)
     #[arg(long)]
@@ -91,34 +91,63 @@ enum StableDiffusionVersion {
     V2_1,
 }
 
-impl Args {
-    fn clip_weights(&self) -> String {
-        match &self.clip_weights {
-            Some(w) => w.clone(),
-            None => match self.sd_version {
-                StableDiffusionVersion::V1_5 => "data/pytorch_model.safetensors".to_string(),
-                StableDiffusionVersion::V2_1 => "data/clip_v2.1.safetensors".to_string(),
-            },
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum ModelFile {
+    Tokenizer,
+    Clip,
+    Unet,
+    Vae,
+}
+
+impl StableDiffusionVersion {
+    fn repo(&self) -> &'static str {
+        match self {
+            Self::V2_1 => "stabilityai/stable-diffusion-2-1",
+            Self::V1_5 => "runwayml/stable-diffusion-v1-5",
         }
     }
 
-    fn vae_weights(&self) -> String {
-        match &self.vae_weights {
-            Some(w) => w.clone(),
-            None => match self.sd_version {
-                StableDiffusionVersion::V1_5 => "data/vae.safetensors".to_string(),
-                StableDiffusionVersion::V2_1 => "data/vae_v2.1.safetensors".to_string(),
-            },
+    fn unet_file(&self) -> &'static str {
+        match self {
+            Self::V1_5 | Self::V2_1 => "unet/diffusion_pytorch_model.safetensors",
         }
     }
 
-    fn unet_weights(&self) -> String {
-        match &self.unet_weights {
-            Some(w) => w.clone(),
-            None => match self.sd_version {
-                StableDiffusionVersion::V1_5 => "data/unet.safetensors".to_string(),
-                StableDiffusionVersion::V2_1 => "data/unet_v2.1.safetensors".to_string(),
-            },
+    fn vae_file(&self) -> &'static str {
+        match self {
+            Self::V1_5 | Self::V2_1 => "vae/diffusion_pytorch_model.safetensors",
+        }
+    }
+
+    fn clip_file(&self) -> &'static str {
+        match self {
+            Self::V1_5 | Self::V2_1 => "text_encoder/model.safetensors",
+        }
+    }
+}
+
+impl ModelFile {
+    const TOKENIZER_REPO: &str = "openai/clip-vit-base-patch32";
+    const TOKENIZER_PATH: &str = "tokenizer.json";
+
+    fn get(
+        &self,
+        filename: Option<String>,
+        version: StableDiffusionVersion,
+    ) -> Result<std::path::PathBuf> {
+        use hf_hub::api::sync::Api;
+        match filename {
+            Some(filename) => Ok(std::path::PathBuf::from(filename)),
+            None => {
+                let (repo, path) = match self {
+                    Self::Tokenizer => (Self::TOKENIZER_REPO, Self::TOKENIZER_PATH),
+                    Self::Clip => (version.repo(), version.clip_file()),
+                    Self::Unet => (version.repo(), version.unet_file()),
+                    Self::Vae => (version.repo(), version.vae_file()),
+                };
+                let filename = Api::new()?.model(repo.to_string()).get(path)?;
+                Ok(filename)
+            }
         }
     }
 }
@@ -151,9 +180,6 @@ fn output_filename(
 }
 
 fn run(args: Args) -> Result<()> {
-    let clip_weights = args.clip_weights();
-    let vae_weights = args.vae_weights();
-    let unet_weights = args.unet_weights();
     let Args {
         prompt,
         uncond_prompt,
@@ -166,6 +192,9 @@ fn run(args: Args) -> Result<()> {
         sliced_attention_size,
         num_samples,
         sd_version,
+        clip_weights,
+        vae_weights,
+        unet_weights,
         ..
     } = args;
     let sd_config = match sd_version {
@@ -180,6 +209,7 @@ fn run(args: Args) -> Result<()> {
     let scheduler = sd_config.build_scheduler(n_steps)?;
     let device = candle_examples::device(cpu)?;
 
+    let tokenizer = ModelFile::Tokenizer.get(tokenizer, sd_version)?;
     let tokenizer = Tokenizer::from_file(tokenizer).map_err(E::msg)?;
     let pad_id = match &sd_config.clip.pad_with {
         Some(padding) => *tokenizer.get_vocab(true).get(padding.as_str()).unwrap(),
@@ -207,14 +237,17 @@ fn run(args: Args) -> Result<()> {
     let uncond_tokens = Tensor::new(uncond_tokens.as_slice(), &device)?.unsqueeze(0)?;
 
     println!("Building the Clip transformer.");
+    let clip_weights = ModelFile::Clip.get(clip_weights, sd_version)?;
     let text_model = sd_config.build_clip_transformer(&clip_weights, &device)?;
     let text_embeddings = text_model.forward(&tokens)?;
     let uncond_embeddings = text_model.forward(&uncond_tokens)?;
     let text_embeddings = Tensor::cat(&[uncond_embeddings, text_embeddings], 0)?;
 
     println!("Building the autoencoder.");
+    let vae_weights = ModelFile::Vae.get(vae_weights, sd_version)?;
     let vae = sd_config.build_vae(&vae_weights, &device)?;
     println!("Building the unet.");
+    let unet_weights = ModelFile::Unet.get(unet_weights, sd_version)?;
     let unet = sd_config.build_unet(&unet_weights, &device, 4)?;
 
     let bsize = 1;