Very simple pyo3 bindings for candle.

.gitignore

@@ -18,3 +18,4 @@ Cargo.lock
 
 perf.data
 flamegraph.svg
+*.so

Cargo.toml

@@ -1,6 +1,7 @@
 [workspace]
 members = [
     "candle-core",
-    "candle-hub",
     "candle-kernels",
+    "candle-hub",
+    "candle-pyo3",
 ]

candle-pyo3/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "candle-pyo3"
+version = "0.1.0"
+edition = "2021"
+
+description = "PyO3 bindings for the candle ML framework."
+repository = "https://github.com/LaurentMazare/candle"
+keywords = ["blas", "tensor", "machine-learning"]
+categories = ["science"]
+license = "MIT/Apache-2.0"
+readme = "README.md"
+
+[lib]
+name = "candle"
+crate-type = ["cdylib"]
+
+[dependencies]
+candle = { path = "../candle-core", default-features=false }
+pyo3 = { version = "0.19.0", features = ["extension-module"] }

candle-pyo3/README.md

@@ -0,0 +1,4 @@
+```
+cargo build --release --package candle-pyo3 --no-default-features && cp -f target/release/libcandle.so candle.so
+PYTHONPATH=. python3 candle-pyo3/test.py
+```

candle-pyo3/src/lib.rs

@@ -0,0 +1,46 @@
+use pyo3::prelude::*;
+use pyo3::{
+    exceptions::PyValueError,
+};
+
+use ::candle::{Tensor, Device::Cpu};
+
+pub fn wrap_err(err: ::candle::Error) -> PyErr {
+    PyErr::new::<PyValueError, _>(format!("{err:?}"))
+}
+
+#[pyclass(name="Tensor")]
+struct PyTensor(Tensor);
+
+impl std::ops::Deref for PyTensor {
+    type Target = Tensor;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+#[pymethods]
+impl PyTensor {
+    #[new]
+    fn new(f: f32) -> PyResult<Self> {
+        Ok(Self(Tensor::new(f, &Cpu).map_err(wrap_err)?))
+    }
+
+    fn __repr__(&self) -> String {
+        format!("{}", self.0)
+    }
+}
+
+#[pyfunction]
+fn add(tensor: &PyTensor, f: f64) -> PyResult<PyTensor> {
+    let tensor = (&tensor.0 + f).map_err(wrap_err)?;
+    Ok(PyTensor(tensor))
+}
+
+#[pymodule]
+fn candle(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
+    m.add_class::<PyTensor>()?;
+    m.add_function(wrap_pyfunction!(add, m)?)?;
+    Ok(())
+}

candle-pyo3/test.py

@@ -0,0 +1,5 @@
+import candle
+
+t = candle.Tensor(42.0)
+print(t)
+print(candle.add(t, 3.14))