Blip fixes (#1145)

* Some fixes for the blip example.

* Stop generating on sep tokens.

* Clippy fixes.

* rustfmt.

candle-examples/examples/blip/main.rs

@@ -4,17 +4,24 @@ extern crate intel_mkl_src;
 #[cfg(feature = "accelerate")]
 extern crate accelerate_src;
 
+use anyhow::Error as E;
 use clap::Parser;
 
-use candle::DType;
+use candle::{DType, Device, Result, Tensor};
+use candle_examples::token_output_stream::TokenOutputStream;
 use candle_nn::VarBuilder;
 use candle_transformers::models::blip;
 
+use tokenizers::Tokenizer;
+
 #[derive(Parser)]
 struct Args {
     #[arg(long)]
     model: Option<String>,
 
+    #[arg(long)]
+    tokenizer: Option<String>,
+
     #[arg(long)]
     image: String,
 
@@ -23,12 +30,33 @@ struct Args {
     cpu: bool,
 }
 
+const SEP_TOKEN_ID: u32 = 102;
+
+/// Loads an image from disk using the image crate, this returns a tensor with shape
+/// (3, 384, 384). OpenAI normalization is applied.
+pub fn load_image<P: AsRef<std::path::Path>>(p: P) -> Result<Tensor> {
+    let img = image::io::Reader::open(p)?
+        .decode()
+        .map_err(candle::Error::wrap)?
+        .resize_to_fill(384, 384, image::imageops::FilterType::Triangle);
+    let img = img.to_rgb8();
+    let data = img.into_raw();
+    let data = Tensor::from_vec(data, (384, 384, 3), &Device::Cpu)?.permute((2, 0, 1))?;
+    let mean =
+        Tensor::new(&[0.48145466f32, 0.4578275, 0.40821073], &Device::Cpu)?.reshape((3, 1, 1))?;
+    let std = Tensor::new(&[0.26862954f32, 0.261_302_6, 0.275_777_1], &Device::Cpu)?
+        .reshape((3, 1, 1))?;
+    (data.to_dtype(candle::DType::F32)? / 255.)?
+        .broadcast_sub(&mean)?
+        .broadcast_div(&std)
+}
+
 pub fn main() -> anyhow::Result<()> {
     let args = Args::parse();
 
     let device = candle_examples::device(args.cpu)?;
 
-    let image = candle_examples::imagenet::load_image224(args.image)?;
+    let image = load_image(args.image)?.to_device(&device)?;
     println!("loaded image {image:?}");
 
     let model_file = match args.model {
@@ -43,12 +71,48 @@ pub fn main() -> anyhow::Result<()> {
         }
         Some(model) => model.into(),
     };
+    let tokenizer = match args.tokenizer {
+        None => {
+            let api = hf_hub::api::sync::Api::new()?;
+            let api = api.model("Salesforce/blip-image-captioning-large".to_string());
+            api.get("tokenizer.json")?
+        }
+        Some(file) => file.into(),
+    };
+    let tokenizer = Tokenizer::from_file(tokenizer).map_err(E::msg)?;
+    let mut tokenizer = TokenOutputStream::new(tokenizer);
+    let mut logits_processor =
+        candle_transformers::generation::LogitsProcessor::new(1337, None, None);
+
     let vb = unsafe { VarBuilder::from_mmaped_safetensors(&[model_file], DType::F32, &device)? };
     let config = blip::Config::image_captioning_large();
     let model = blip::BlipForConditionalGeneration::new(&config, vb)?;
+    let vision_model = model.vision_model();
+    let text_decoder = model.text_decoder();
     println!("model built");
     // TODO: Maybe add support for the conditional prompt.
-    let out = model.generate(&image.unsqueeze(0)?, None, None)?;
-    println!(">>>\n{out}");
+    let image_embeds = image.unsqueeze(0)?.apply(vision_model)?;
+
+    let mut token_ids = vec![30522u32];
+    for _index in 0..1000 {
+        let input_ids = Tensor::new(token_ids.as_slice(), &device)?.broadcast_left(1)?;
+        let logits = text_decoder.forward(&input_ids, &image_embeds)?;
+        let logits = logits.squeeze(0)?;
+        let logits = logits.get(logits.dim(0)? - 1)?;
+        let token = logits_processor.sample(&logits)?;
+        if token == SEP_TOKEN_ID {
+            break;
+        }
+        token_ids.push(token);
+        if let Some(t) = tokenizer.next_token(token)? {
+            use std::io::Write;
+            print!("{t}");
+            std::io::stdout().flush()?;
+        }
+    }
+    if let Some(rest) = tokenizer.decode_rest().map_err(E::msg)? {
+        print!("{rest}");
+    }
+
     Ok(())
 }