Add a quantized test that use negative values. (#470)

* Add a quantized test that use negative values.

* Add a default tokenizer.

candle-core/tests/quantized_tests.rs

@@ -1,5 +1,7 @@
 use candle_core::{quantized, Device, Result, Tensor};
 use quantized::{k_quants, GgmlType};
+mod test_utils;
+use test_utils::to_vec2_round;
 
 #[test]
 fn quantized_matmul() -> Result<()> {
@@ -45,6 +47,54 @@ fn quantized_matmul() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn quantized_matmul_neg() -> Result<()> {
+    let cpu = &Device::Cpu;
+    let (m, k, n) = (3, 64, 4);
+    let lhs = (0..(m * k))
+        .map(|v| v as f32 - (m * k) as f32 / 2.0)
+        .collect::<Vec<_>>();
+    let tensor_lhs = Tensor::from_slice(&lhs, (m, k), cpu)?;
+    let mut dst = vec![42.; 3 * 4];
+    let mut rhs_t = vec![k_quants::BlockQ4_0::zeros(); 8];
+    let rhs = (0..k * n)
+        .map(|v| v as f32 - (k * n) as f32 / 3.0)
+        .collect::<Vec<_>>();
+    let tensor_rhs = Tensor::from_slice(&rhs, (n, k), cpu)?.t()?;
+    k_quants::BlockQ4_0::from_float(&rhs, &mut rhs_t)?;
+    k_quants::matmul((m, k, n), &lhs, &rhs_t, &mut dst)?;
+    assert_eq!(
+        dst,
+        &[
+            243524.14, -19596.34, -285051.3, -549814.94, 23776.629, 21650.926, 19397.924,
+            18366.586, -196472.1, 63011.6, 324584.56, 587901.9
+        ]
+    );
+    let mm = tensor_lhs.matmul(&tensor_rhs)?;
+    assert_eq!(
+        to_vec2_round(&mm, 0)?,
+        &[
+            [244064.0, -20128.0, -284320.0, -548512.0],
+            [23563.0, 21515.0, 19467.0, 17419.0],
+            [-196939.0, 63157.0, 323253.0, 583349.0]
+        ]
+    );
+
+    let qtensor = quantized::QTensor::new(rhs_t, (4, 64));
+    let matmul = quantized::QMatMul::from_qtensor(qtensor);
+    let res = matmul.forward(&tensor_lhs)?;
+    assert_eq!(
+        to_vec2_round(&res, 0)?,
+        &[
+            [243524.0, -19596.0, -285051.0, -549815.0],
+            [23777.0, 21651.0, 19398.0, 18367.0],
+            [-196472.0, 63012.0, 324585.0, 587902.0]
+        ]
+    );
+
+    Ok(())
+}
+
 #[test]
 fn quantize_q4_0() -> Result<()> {
     use k_quants::BlockQ4_0;