Pyo3 dtype (#327)

* Better handling of dtypes in pyo3.

* More pyo3 dtype.

candle-pyo3/src/lib.rs

@@ -40,21 +40,30 @@ impl std::ops::Deref for PyTensor {
 }
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
+#[pyclass(name = "DType")]
 struct PyDType(DType);
 
-impl<'source> FromPyObject<'source> for PyDType {
-    fn extract(ob: &'source PyAny) -> PyResult<Self> {
-        use std::str::FromStr;
-        let dtype: &str = ob.extract()?;
-        let dtype = DType::from_str(dtype)
-            .map_err(|_| PyTypeError::new_err(format!("invalid dtype '{dtype}'")))?;
-        Ok(Self(dtype))
+#[pymethods]
+impl PyDType {
+    fn __repr__(&self) -> String {
+        format!("{:?}", self.0)
+    }
+
+    fn __str__(&self) -> String {
+        self.__repr__()
     }
 }
 
-impl ToPyObject for PyDType {
-    fn to_object(&self, py: Python<'_>) -> PyObject {
-        self.0.as_str().to_object(py)
+impl PyDType {
+    fn from_pyobject(ob: PyObject, py: Python<'_>) -> PyResult<Self> {
+        use std::str::FromStr;
+        if let Ok(dtype) = ob.extract::<&str>(py) {
+            let dtype = DType::from_str(dtype)
+                .map_err(|_| PyTypeError::new_err(format!("invalid dtype '{dtype}'")))?;
+            Ok(Self(dtype))
+        } else {
+            ob.extract(py)
+        }
     }
 }
 
@@ -223,8 +232,8 @@ impl PyTensor {
     }
 
     #[getter]
-    fn dtype(&self, py: Python<'_>) -> PyObject {
-        PyDType(self.0.dtype()).to_object(py)
+    fn dtype(&self) -> PyDType {
+        PyDType(self.0.dtype())
     }
 
     #[getter]
@@ -367,7 +376,8 @@ impl PyTensor {
         Ok(PyTensor(self.0.copy().map_err(wrap_err)?))
     }
 
-    fn to_dtype(&self, dtype: PyDType) -> PyResult<Self> {
+    fn to_dtype(&self, dtype: PyObject, py: Python<'_>) -> PyResult<Self> {
+        let dtype = PyDType::from_pyobject(dtype, py)?;
         Ok(PyTensor(self.0.to_dtype(dtype.0).map_err(wrap_err)?))
     }
 
@@ -416,12 +426,15 @@ fn randn(_py: Python<'_>, shape: PyShape, device: Option<PyDevice>) -> PyResult<
 #[pyfunction]
 #[pyo3(signature = (shape, *, dtype=None, device=None))]
 fn ones(
-    _py: Python<'_>,
+    py: Python<'_>,
     shape: PyShape,
-    dtype: Option<PyDType>,
+    dtype: Option<PyObject>,
     device: Option<PyDevice>,
 ) -> PyResult<PyTensor> {
-    let dtype = dtype.map_or(DType::F32, |dt| dt.0);
+    let dtype = match dtype {
+        None => DType::F32,
+        Some(dtype) => PyDType::from_pyobject(dtype, py)?.0,
+    };
     let device = device.unwrap_or(PyDevice::Cpu).as_device()?;
     let tensor = Tensor::ones(shape.0, dtype, &device).map_err(wrap_err)?;
     Ok(PyTensor(tensor))
@@ -430,12 +443,15 @@ fn ones(
 #[pyfunction]
 #[pyo3(signature = (shape, *, dtype=None, device=None))]
 fn zeros(
-    _py: Python<'_>,
+    py: Python<'_>,
     shape: PyShape,
-    dtype: Option<PyDType>,
+    dtype: Option<PyObject>,
     device: Option<PyDevice>,
 ) -> PyResult<PyTensor> {
-    let dtype = dtype.map_or(DType::F32, |dt| dt.0);
+    let dtype = match dtype {
+        None => DType::F32,
+        Some(dtype) => PyDType::from_pyobject(dtype, py)?.0,
+    };
     let device = device.unwrap_or(PyDevice::Cpu).as_device()?;
     let tensor = Tensor::zeros(shape.0, dtype, &device).map_err(wrap_err)?;
     Ok(PyTensor(tensor))
@@ -444,6 +460,13 @@ fn zeros(
 #[pymodule]
 fn candle(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
     m.add_class::<PyTensor>()?;
+    m.add_class::<PyDType>()?;
+    m.add("u8", PyDType(DType::U8))?;
+    m.add("u32", PyDType(DType::U32))?;
+    m.add("bf16", PyDType(DType::BF16))?;
+    m.add("f16", PyDType(DType::F16))?;
+    m.add("f32", PyDType(DType::F32))?;
+    m.add("f64", PyDType(DType::F64))?;
     m.add_function(wrap_pyfunction!(cat, m)?)?;
     m.add_function(wrap_pyfunction!(ones, m)?)?;
     m.add_function(wrap_pyfunction!(rand, m)?)?;