add float16

fastdeploy/pybind/main.h

@@ -100,3 +100,32 @@ std::vector<pybind11::array> PyBackendInfer(
 }
 
 }  // namespace fastdeploy
+
+namespace pybind11 {
+namespace detail {
+
+// Note: use same enum number of float16 in numpy.
+// import numpy as np
+// print np.dtype(np.float16).num  # 23
+constexpr int NPY_FLOAT16_ = 23;
+
+// Note: Since float16 is not a builtin type in C++, we register
+// fastdeploy::float16 as numpy.float16.
+// Ref: https://github.com/pybind/pybind11/issues/1776
+template <>
+struct npy_format_descriptor<fastdeploy::float16> {
+  static pybind11::dtype dtype() {
+    handle ptr = npy_api::get().PyArray_DescrFromType_(NPY_FLOAT16_);
+    return reinterpret_borrow<pybind11::dtype>(ptr);
+  }
+  static std::string format() {
+    // Note: "e" represents float16.
+    // Details at:
+    // https://docs.python.org/3/library/struct.html#format-characters.
+    return "e";
+  }
+  static constexpr auto name = _("float16");
+};
+
+}  // namespace detail
+}  // namespace pybind11