[MPS][BE] Migrate polar to use functor (pytorch#147184)

Pull Request resolved: pytorch#147184
Approved by: https://github.com/dcci
ghstack dependencies: pytorch#147182, pytorch#147183

Author: malfet

aten/src/ATen/native/mps/kernels/BinaryKernel.metal

@@ -1,4 +1,5 @@
 #include <c10/metal/special_math.h>
+#include <c10/metal/utils.h>
 #include <metal_stdlib>
 using namespace metal;
 
@@ -74,6 +75,15 @@ struct nextafter_functor {
   }
 };
 
+struct polar_functor {
+  template <typename U>
+  using ret_type = c10::metal::vec2type_t<U>;
+  template <typename T>
+  inline ret_type<T> operator()(const T a, const T b) {
+    return ret_type<T>(a * cos(b), a * sin(b));
+  }
+};
+
 // Future BinaryTensorIterator
 template <typename T, typename F>
 using result_of = decltype(::metal::declval<F>()(
@@ -153,22 +163,8 @@ REGISTER_BINARY_INDEXING_OP(zeta, bfloat);
 #endif
 
 // Complex binary functions
-template <typename T>
-kernel void polar(
-    constant void* abs_ [[buffer(0)]],
-    constant void* angle_ [[buffer(1)]],
-    device void* out_ [[buffer(2)]],
-    constant uint3* offsets [[buffer(3)]],
-    uint tid [[thread_position_in_grid]]) {
-  device T* out = (device T*)((device uint8_t*)out_ + offsets[tid].x);
-  constant T* angle = (constant T*)((constant uint8_t*)angle_ + offsets[tid].z);
-  constant T* abs = (constant T*)((constant uint8_t*)abs_ + offsets[tid].y);
-  out[0] = abs[0] * cos(angle[0]);
-  out[1] = abs[0] * sin(angle[0]);
-}
-
-REGISTER_BINARY_OP(polar, float);
-REGISTER_BINARY_OP(polar, half);
+REGISTER_BINARY_INDEXING_OP(polar, float);
+REGISTER_BINARY_INDEXING_OP(polar, half);
 
 template <typename T>
 kernel void complex_mul(

aten/src/ATen/native/mps/operations/BinaryKernel.mm

@@ -141,7 +141,7 @@ static void zeta_mps_kernel(TensorIteratorBase& iter) {
   auto output_as_real = at::view_as_real(output).select(output.dim(), 0);
   auto iter = TensorIteratorConfig().add_output(output_as_real).add_input(abs).add_input(angle).build();
 
-  mps::binary_mps_impl(iter, "polar", false);
+  mps::binary_mps_impl(iter, "polar");
   return output;
 }