From bc40ccf6aab3093efb1f765f9c0599384d2a0fb6 Mon Sep 17 00:00:00 2001
From: Aaron Gokaslan <aaronGokaslan@gmail.com>
Date: Fri, 7 Feb 2025 05:15:11 +0000
Subject: [PATCH] [BE]: Inline special functions for MPS (#146627)

These header functions should be inlined for consistency and to avoid translation unit / symbol issues.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/146627
Approved by: https://github.com/dcci
---
 c10/metal/special_math.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/c10/metal/special_math.h b/c10/metal/special_math.h
index c28640afa26..8bcb1f7a53e 100644
--- a/c10/metal/special_math.h
+++ b/c10/metal/special_math.h
@@ -8,7 +8,7 @@ namespace metal {
 // Translated to metal from https://www.johndcook.com/cpp_erf.html
 
 template <typename T>
-T erf(T x) {
+inline T erf(T x) {
   T a1 = 0.254829592;
   T a2 = -0.284496736;
   T a3 = 1.421413741;
@@ -86,7 +86,7 @@ inline T chbevl(T x, const float array[], const int len) {
 // https://github.com/pytorch/pytorch/blob/58b661cda2c002a8e1ac3bee494bfe1f7420437c/aten/src/ATen/native/cuda/Math.cuh#L502
 
 template <typename T>
-T i0(T _x) {
+inline T i0(T _x) {
   auto x = ::metal::fabs(_x);
 
   if (x <= 8.0) {
@@ -145,7 +145,7 @@ T i0(T _x) {
 // https://github.com/pytorch/pytorch/blob/58b661cda2c002a8e1ac3bee494bfe1f7420437c/aten/src/ATen/native/cuda/Math.cuh#L576
 
 template <typename T>
-T i1(T _x) {
+inline T i1(T _x) {
   const auto x = ::metal::fabs(_x);
 
   if (x <= 8.0) {
@@ -199,7 +199,7 @@ template <typename T>
 inline float log_gamma(const T);
 
 template <typename T>
-float gamma(const T x) {
+inline float gamma(const T x) {
   if (x < 0.001) {
     constexpr float EULER_MASCHERONI = 0.577215664901532860606512090;
     // For small x, 1/gamma(x) has power series x + gamma x^2  - ...
@@ -452,7 +452,7 @@ inline float digamma(T0 x) {
 }
 
 template <typename T>
-T sinc(T a) {
+inline T sinc(T a) {
   if (a == static_cast<T>(0)) {
     return static_cast<T>(1);
   }