added complex64 and python tests

mlx/safetensor.cpp

@@ -29,6 +29,8 @@ std::string dtype_to_safetensor_str(Dtype t) {
     return ST_U8;
   } else if (t == bool_) {
     return ST_BOOL;
+  } else if (t == complex64) {
+    return ST_C64;
   } else {
     throw std::runtime_error("[safetensor] unsupported dtype");
   }
@@ -59,6 +61,8 @@ Dtype dtype_from_safetensor_str(std::string str) {
     return uint8;
   } else if (str == ST_BOOL) {
     return bool_;
+  } else if (str == ST_C64) {
+    return complex64;
   } else {
     throw std::runtime_error("[safetensor] unsupported dtype " + str);
   }

mlx/safetensor.h

@@ -25,4 +25,8 @@ namespace mlx::core {
 #define ST_U16 "U16"
 #define ST_U32 "U32"
 #define ST_U64 "U64"
+
+// Note: Complex numbers aren't in the spec yet so this could change -
+// https://github.com/huggingface/safetensors/issues/389
+#define ST_C64 "C64"
 } // namespace mlx::core

python/tests/test_load.py

@@ -64,6 +64,33 @@ class TestLoad(mlx_tests.MLXTestCase):
                         load_arr_mlx_npy = np.load(save_file_mlx)
                         self.assertTrue(np.array_equal(load_arr_mlx_npy, save_arr_npy))
 
+    def test_save_and_load_safetensor(self):
+        if not os.path.isdir(self.test_dir):
+            os.mkdir(self.test_dir)
+
+        for dt in self.dtypes + ["bfloat16"]:
+            with self.subTest(dtype=dt):
+                for i, shape in enumerate([(1,), (23,), (1024, 1024), (4, 6, 3, 1, 2)]):
+                    with self.subTest(shape=shape):
+                        save_file_mlx = os.path.join(
+                            self.test_dir, f"mlx_{dt}_{i}_fs.safetensors"
+                        )
+                        save_dict = {
+                            "test": mx.random.normal(shape=shape, dtype=getattr(mx, dt))
+                            if dt in ["float32", "float16", "bfloat16"]
+                            else mx.ones(shape, dtype=getattr(mx, dt))
+                        }
+
+                        with open(save_file_mlx, "wb") as f:
+                            mx.save_safetensor(f, save_dict)
+                        with open(save_file_mlx, "rb") as f:
+                            load_dict = mx.load_safetensor(f)
+
+                        self.assertTrue("test" in load_dict)
+                        self.assertTrue(
+                            mx.array_equal(load_dict["test"], save_dict["test"])
+                        )
+
     def test_save_and_load_fs(self):
 
         if not os.path.isdir(self.test_dir):