Support for quantized tensors in the python api. (#706)

* Add more pyo3 support.

* Add some support for quantized tensors in pyo3.

* Add an arc layer on qmatmul.

* Add the quantized matmul.

* Quantization support.

* More quantization support.

* Test the python quantization.

candle-core/src/quantized/mod.rs

@@ -230,12 +230,20 @@ impl QTensor {
 }
 
 #[derive(Debug)]
-pub struct QMatMul(QTensor);
+pub struct QMatMul(std::sync::Arc<QTensor>);
 
 impl QMatMul {
-    pub fn from_qtensor(qtensor: QTensor) -> Self {
+    pub fn from_arc(qtensor: std::sync::Arc<QTensor>) -> Self {
         Self(qtensor)
     }
+
+    pub fn from_qtensor(qtensor: QTensor) -> Self {
+        Self(std::sync::Arc::new(qtensor))
+    }
+
+    pub fn inner(&self) -> &std::sync::Arc<QTensor> {
+        &self.0
+    }
 }
 
 impl crate::CustomOp1 for QTensor {
@@ -279,6 +287,6 @@ impl crate::CustomOp1 for QTensor {
 
 impl QMatMul {
     pub fn forward(&self, xs: &Tensor) -> Result<Tensor> {
-        xs.apply_op1_no_bwd(&self.0)
+        xs.apply_op1_no_bwd(self.0.as_ref())
     }
 }

candle-pyo3/src/lib.rs

@@ -3,10 +3,11 @@
 use pyo3::exceptions::{PyTypeError, PyValueError};
 use pyo3::prelude::*;
 use pyo3::types::PyTuple;
+use std::sync::Arc;
 
 use half::{bf16, f16};
 
-use ::candle::{DType, Device, Tensor, WithDType};
+use ::candle::{quantized::QTensor, DType, Device, Tensor, WithDType};
 
 pub fn wrap_err(err: ::candle::Error) -> PyErr {
     PyErr::new::<PyValueError, _>(format!("{err:?}"))
@@ -261,6 +262,38 @@ impl PyTensor {
         self.__repr__()
     }
 
+    fn sin(&self) -> PyResult<Self> {
+        Ok(PyTensor(self.0.sin().map_err(wrap_err)?))
+    }
+
+    fn cos(&self) -> PyResult<Self> {
+        Ok(PyTensor(self.0.cos().map_err(wrap_err)?))
+    }
+
+    fn log(&self) -> PyResult<Self> {
+        Ok(PyTensor(self.0.log().map_err(wrap_err)?))
+    }
+
+    fn sqr(&self) -> PyResult<Self> {
+        Ok(PyTensor(self.0.sqr().map_err(wrap_err)?))
+    }
+
+    fn sqrt(&self) -> PyResult<Self> {
+        Ok(PyTensor(self.0.sqrt().map_err(wrap_err)?))
+    }
+
+    fn recip(&self) -> PyResult<Self> {
+        Ok(PyTensor(self.0.recip().map_err(wrap_err)?))
+    }
+
+    fn exp(&self) -> PyResult<Self> {
+        Ok(PyTensor(self.0.exp().map_err(wrap_err)?))
+    }
+
+    fn powf(&self, p: f64) -> PyResult<Self> {
+        Ok(PyTensor(self.0.powf(p).map_err(wrap_err)?))
+    }
+
     fn matmul(&self, rhs: &Self) -> PyResult<Self> {
         Ok(PyTensor(self.0.matmul(rhs).map_err(wrap_err)?))
     }
@@ -344,8 +377,12 @@ impl PyTensor {
         Ok(PyTensor(self.0.narrow(dim, start, len).map_err(wrap_err)?))
     }
 
-    fn sum_keepdim(&self, dims: Vec<usize>) -> PyResult<Self> {
-        // TODO: Support a single dim as input?
+    fn sum_keepdim(&self, dims: PyObject, py: Python<'_>) -> PyResult<Self> {
+        let dims = if let Ok(dim) = dims.extract::<usize>(py) {
+            vec![dim]
+        } else {
+            dims.extract::<Vec<usize>>(py)?
+        };
         Ok(PyTensor(
             self.0.sum_keepdim(dims.as_slice()).map_err(wrap_err)?,
         ))
@@ -355,6 +392,13 @@ impl PyTensor {
         Ok(PyTensor(self.0.sum_all().map_err(wrap_err)?))
     }
 
+    fn mean_all(&self) -> PyResult<Self> {
+        let elements = self.0.elem_count();
+        let sum = self.0.sum_all().map_err(wrap_err)?;
+        let mean = (sum / elements as f64).map_err(wrap_err)?;
+        Ok(PyTensor(mean))
+    }
+
     fn flatten_all(&self) -> PyResult<Self> {
         Ok(PyTensor(self.0.flatten_all().map_err(wrap_err)?))
     }
@@ -392,6 +436,32 @@ impl PyTensor {
         let device = device.as_device()?;
         Ok(PyTensor(self.0.to_device(&device).map_err(wrap_err)?))
     }
+
+    fn quantize(&self, quantized_dtype: &str) -> PyResult<PyQTensor> {
+        use ::candle::quantized;
+        let res = match quantized_dtype {
+            "q2k" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ2K>(self),
+            "q3k" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ3K>(self),
+            "q4_0" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ4_0>(self),
+            "q4_1" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ4_1>(self),
+            "q4k" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ4K>(self),
+            "q5_0" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ5_0>(self),
+            "q5_1" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ5_1>(self),
+            "q5k" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ5K>(self),
+            "q6k" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ6K>(self),
+            "q8_0" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ8_0>(self),
+            "q8_1" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ8_1>(self),
+            "q8k" => quantized::QTensor::quantize::<quantized::k_quants::BlockQ8K>(self),
+            "f16" => quantized::QTensor::quantize::<f16>(self),
+            "f32" => quantized::QTensor::quantize::<f32>(self),
+            dt => {
+                return Err(PyErr::new::<PyValueError, _>(format!(
+                    "unknown quantized-dtype {dt}"
+                )))
+            }
+        };
+        Ok(PyQTensor(Arc::new(res.map_err(wrap_err)?)))
+    }
 }
 
 /// Concatenate the tensors across one axis.
@@ -464,9 +534,90 @@ fn zeros(
     Ok(PyTensor(tensor))
 }
 
+#[derive(Debug)]
+#[pyclass(name = "QTensor")]
+struct PyQTensor(Arc<QTensor>);
+
+impl std::ops::Deref for PyQTensor {
+    type Target = QTensor;
+
+    fn deref(&self) -> &Self::Target {
+        self.0.as_ref()
+    }
+}
+
+#[pymethods]
+impl PyQTensor {
+    #[getter]
+    fn ggml_dtype(&self) -> String {
+        format!("{:?}", self.0.dtype())
+    }
+
+    #[getter]
+    fn rank(&self) -> usize {
+        self.0.rank()
+    }
+
+    #[getter]
+    fn shape(&self, py: Python<'_>) -> PyObject {
+        PyTuple::new(py, self.0.shape().dims()).to_object(py)
+    }
+
+    fn __repr__(&self) -> String {
+        format!("{:?}", self.0)
+    }
+
+    fn __str__(&self) -> String {
+        self.__repr__()
+    }
+
+    fn dequantize(&self) -> PyResult<PyTensor> {
+        let tensor = self.0.dequantize(&Device::Cpu).map_err(wrap_err)?;
+        Ok(PyTensor(tensor))
+    }
+
+    fn matmul_t(&self, lhs: &PyTensor) -> PyResult<PyTensor> {
+        let qmatmul = ::candle::quantized::QMatMul::from_arc(self.0.clone());
+        let res = qmatmul.forward(lhs).map_err(wrap_err)?;
+        Ok(PyTensor(res))
+    }
+}
+
+#[pyfunction]
+fn cuda_is_available() -> bool {
+    ::candle::utils::cuda_is_available()
+}
+
+#[pyfunction]
+fn has_accelerate() -> bool {
+    ::candle::utils::has_accelerate()
+}
+
+#[pyfunction]
+fn has_mkl() -> bool {
+    ::candle::utils::has_mkl()
+}
+
+#[pyfunction]
+fn get_num_threads() -> usize {
+    ::candle::utils::get_num_threads()
+}
+
+fn candle_utils(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
+    m.add_function(wrap_pyfunction!(cuda_is_available, m)?)?;
+    m.add_function(wrap_pyfunction!(get_num_threads, m)?)?;
+    m.add_function(wrap_pyfunction!(has_accelerate, m)?)?;
+    m.add_function(wrap_pyfunction!(has_mkl, m)?)?;
+    Ok(())
+}
+
 #[pymodule]
-fn candle(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
+fn candle(py: Python<'_>, m: &PyModule) -> PyResult<()> {
+    let utils = PyModule::new(py, "utils")?;
+    candle_utils(py, utils)?;
+    m.add_submodule(utils)?;
     m.add_class::<PyTensor>()?;
+    m.add_class::<PyQTensor>()?;
     m.add_class::<PyDType>()?;
     m.add("u8", PyDType(DType::U8))?;
     m.add("u32", PyDType(DType::U32))?;

candle-pyo3/test.py

@@ -33,3 +33,9 @@ print(t.to_dtype("u8"))
 t = candle.randn((5, 3))
 print(t)
 print(t.dtype)
+
+t = candle.randn((16, 256))
+quant_t = t.quantize("q6k")
+dequant_t = quant_t.dequantize()
+diff2 = (t - dequant_t).sqr()
+print(diff2.mean_all())