Add ColPali (#2524)

* add colpali

* cleanup

* fix clippy

candle-transformers/src/models/colpali.rs

@@ -0,0 +1,42 @@
+use candle::{Module, Result, Tensor};
+use candle_nn::VarBuilder;
+
+use super::paligemma;
+use candle_nn::{linear, Linear};
+
+pub struct Model {
+    pub model: paligemma::Model,
+    pub custom_text_projection: Linear,
+}
+
+impl Model {
+    pub fn new(config: &paligemma::Config, vb: VarBuilder) -> Result<Self> {
+        let model = paligemma::Model::new(config, vb.pp("model"))?;
+        let custom_text_projection = linear(
+            config.text_config.hidden_size,
+            128,
+            vb.pp("custom_text_proj"),
+        )?;
+
+        Ok(Self {
+            model,
+            custom_text_projection,
+        })
+    }
+
+    pub fn forward_images(&mut self, pixel_values: &Tensor, input_ids: &Tensor) -> Result<Tensor> {
+        let outputs = self
+            .model
+            .setup_without_projection(pixel_values, input_ids)?;
+        let outputs = self.custom_text_projection.forward(&outputs)?;
+        let outputs = outputs.broadcast_div(&outputs.sqr()?.sum_keepdim(2)?.sqrt()?)?;
+        Ok(outputs)
+    }
+
+    pub fn forward_text(&mut self, input_ids: &Tensor) -> Result<Tensor> {
+        let outputs = self.model.forward_without_projection(input_ids)?;
+        let outputs = self.custom_text_projection.forward(&outputs)?;
+        let outputs = outputs.broadcast_div(&outputs.sqr()?.sum_keepdim(2)?.sqrt()?)?;
+        Ok(outputs)
+    }
+}