Added Cohere example [skip ci]

README.md

@@ -17,6 +17,7 @@ Follow the instructions for your database library:
 Or check out some examples:
 
 - [Embeddings](https://github.com/pgvector/pgvector-rust/blob/master/examples/openai/src/main.rs) with OpenAI
+- [Binary embeddings](https://github.com/pgvector/pgvector-rust/blob/master/examples/cohere/src/main.rs) with Cohere
 - [Recommendations](https://github.com/pgvector/pgvector-rust/blob/master/examples/disco/src/main.rs) with Disco
 - [Bulk loading](https://github.com/pgvector/pgvector-rust/blob/master/examples/loading/src/main.rs) with `COPY`
 

examples/cohere/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "example"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[dependencies]
+pgvector = { path = "../..", features = ["postgres"] }
+postgres = "0.19"
+serde_json = "1"
+ureq = { version = "2", features = ["json"] }

examples/cohere/src/main.rs

@@ -0,0 +1,65 @@
+use pgvector::Bit;
+use postgres::{Client, NoTls};
+use serde_json::Value;
+use std::error::Error;
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let mut client = Client::configure()
+        .host("localhost")
+        .dbname("pgvector_example")
+        .user(std::env::var("USER")?.as_str())
+        .connect(NoTls)?;
+
+    client.execute("CREATE EXTENSION IF NOT EXISTS vector", &[])?;
+    client.execute("DROP TABLE IF EXISTS documents", &[])?;
+    client.execute("CREATE TABLE documents (id serial PRIMARY KEY, content text, embedding bit(1024))", &[])?;
+
+    let input = [
+        "The dog is barking",
+        "The cat is purring",
+        "The bear is growling",
+    ];
+    let embeddings = fetch_embeddings(&input, "search_document")?;
+    for (content, embedding) in input.iter().zip(embeddings) {
+        let embedding = Bit::from_bytes(&embedding);
+        client.execute("INSERT INTO documents (content, embedding) VALUES ($1, $2)", &[&content, &embedding])?;
+    }
+
+    let query = "forest";
+    let query_embedding = fetch_embeddings(&[query], "search_query")?;
+    for row in client.query("SELECT content FROM documents ORDER BY embedding <~> $1 LIMIT 5", &[&Bit::from_bytes(&query_embedding[0])])? {
+        let content: &str = row.get(0);
+        println!("{}", content);
+    }
+
+    Ok(())
+}
+
+fn fetch_embeddings(texts: &[&str], input_type: &str) -> Result<Vec<Vec<u8>>, Box<dyn Error>> {
+    let api_key = std::env::var("CO_API_KEY").or(Err("Set CO_API_KEY"))?;
+
+    let response: Value = ureq::post("https://api.cohere.com/v1/embed")
+        .set("Authorization", &format!("Bearer {}", api_key))
+        .send_json(ureq::json!({
+            "texts": texts,
+            "model": "embed-english-v3.0",
+            "input_type": input_type,
+            "embedding_types": &["ubinary"],
+        }))?
+        .into_json()?;
+
+    let embeddings = response["embeddings"]["ubinary"]
+        .as_array()
+        .unwrap()
+        .iter()
+        .map(|v| {
+            v.as_array()
+                .unwrap()
+                .iter()
+                .map(|v| v.as_f64().unwrap() as u8)
+                .collect()
+        })
+        .collect();
+
+    Ok(embeddings)
+}