Implement top_p / nucleus sampling (#819)

* Implement top_p / nucleus sampling

* Update changelog

* rustfmt

* Add tests

* Fix clippy warning

* Fix another clippy error

1 files changed, 8 insertions, 2 deletions

diff --git a/candle-wasm-examples/llama2-c/src/bin/m.rs b/candle-wasm-examples/llama2-c/src/bin/m.rs
index 6628ab7e..61de9d7f 100644
--- a/candle-wasm-examples/llama2-c/src/bin/m.rs
+++ b/candle-wasm-examples/llama2-c/src/bin/m.rs
@@ -47,7 +47,7 @@ impl Model {
             tokenizer,
             model: weights,
         });
-        let logits_processor = LogitsProcessor::new(299792458, None);
+        let logits_processor = LogitsProcessor::new(299792458, None, None);
         match model {
             Ok(inner) => Ok(Self {
                 inner,
@@ -69,6 +69,7 @@ impl Model {
         &mut self,
         prompt: String,
         temp: f64,
+        top_p: f64,
         repeat_penalty: f32,
         seed: u64,
     ) -> Result<String, JsError> {
@@ -80,7 +81,12 @@ impl Model {
             }
         }
         let temp = if temp <= 0. { None } else { Some(temp) };
-        self.logits_processor = LogitsProcessor::new(seed, temp);
+        let top_p = if top_p <= 0. || top_p >= 1. {
+            None
+        } else {
+            Some(top_p)
+        };
+        self.logits_processor = LogitsProcessor::new(seed, temp, top_p);
         self.repeat_penalty = repeat_penalty;
         self.tokens.clear();
         let tokens = self