From 7505783cc76bb45b059413c6eb0cd0e98131d6de Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sun, 14 Mar 2021 19:45:41 -0700
Subject: [PATCH] ircd::math: Add fallback for vectorized hyperbolic tangent.

---
 include/ircd/math/math.h |  7 +++++++
 include/ircd/math/tanh.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 include/ircd/math/tanh.h

diff --git a/include/ircd/math/math.h b/include/ircd/math/math.h
index 88a423e5b..76bcacda3 100644
--- a/include/ircd/math/math.h
+++ b/include/ircd/math/math.h
@@ -14,3 +14,10 @@
 #include "log2.h"
 #include "inv.h"
 #include "mean.h"
+#include "tanh.h"
+
+namespace ircd
+{
+	using math::mean;
+	using math::tanh;
+}
diff --git a/include/ircd/math/tanh.h b/include/ircd/math/tanh.h
new file mode 100644
index 000000000..ed921e22c
--- /dev/null
+++ b/include/ircd/math/tanh.h
@@ -0,0 +1,29 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#pragma once
+#define HAVE_IRCD_MATH_TANH_H
+
+namespace ircd::math
+{
+	template<class T>
+	typename std::enable_if<simd::is<T>(), T>::type
+	tanh(T);
+}
+
+template<class T>
+inline typename std::enable_if<ircd::simd::is<T>(), T>::type
+ircd::math::tanh(T a)
+{
+	for(uint i(0); i < simd::lanes<T>(); ++i)
+		a[i] = std::tanh(a[i]);
+
+	return a;
+}