From 99efd386f760b279d085a0ea4f4b50822343d8d6 Mon Sep 17 00:00:00 2001
From: Vincent Esche <regexident@gmail.com>
Date: Tue, 24 Sep 2019 14:11:31 +0200
Subject: [PATCH] =?UTF-8?q?Added=20`muladd`/`muladdInPlace`=20to=20?=
 =?UTF-8?q?=E2=80=98Arithmetic.swift=E2=80=99?=
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---
 Sources/Surge/Arithmetic/Arithmetic.swift | 36 +++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/Sources/Surge/Arithmetic/Arithmetic.swift b/Sources/Surge/Arithmetic/Arithmetic.swift
index de7d69d..0caea49 100644
--- a/Sources/Surge/Arithmetic/Arithmetic.swift
+++ b/Sources/Surge/Arithmetic/Arithmetic.swift
@@ -220,6 +220,42 @@ public func .-= <L: UnsafeMutableMemoryAccessible, R: UnsafeMemoryAccessible>(lh
     return subInPlace(&lhs, rhs)
 }
 
+// MARK: - Multiply Addition
+
+func muladd<L: UnsafeMemoryAccessible, R: UnsafeMemoryAccessible>(_ lhs: L, _ rhs: R, _ alpha: Float) -> [Float] where L.Element == Float, R.Element == Float {
+    var results = Array(lhs)
+    muladdInPlace(&results, rhs, alpha)
+    return results
+}
+
+func muladd<L: UnsafeMemoryAccessible, R: UnsafeMemoryAccessible>(_ lhs: L, _ rhs: R, _ alpha: Double) -> [Double] where L.Element == Double, R.Element == Double {
+    var results = Array(lhs)
+    muladdInPlace(&results, rhs, alpha)
+    return results
+}
+
+// MARK: - Multiply Addition: In Place
+
+func muladdInPlace<L: UnsafeMutableMemoryAccessible, R: UnsafeMemoryAccessible>(_ lhs: inout L, _ rhs: R, _ alpha: Float) where L.Element == Float, R.Element == Float {
+    precondition(lhs.count == rhs.count, "Collections must have the same size")
+    let elementCount: Int32 = numericCast(lhs.count)
+    lhs.withUnsafeMutableMemory { lhsMemory in
+        rhs.withUnsafeMemory { rhsMemory in
+            cblas_saxpy(elementCount, alpha, rhsMemory.pointer, numericCast(rhsMemory.stride), lhsMemory.pointer, numericCast(lhsMemory.stride))
+        }
+    }
+}
+
+func muladdInPlace<L: UnsafeMutableMemoryAccessible, R: UnsafeMemoryAccessible>(_ lhs: inout L, _ rhs: R, _ alpha: Double) where L.Element == Double, R.Element == Double {
+    precondition(lhs.count == rhs.count, "Collections must have the same size")
+    let elementCount: Int32 = numericCast(lhs.count)
+    lhs.withUnsafeMutableMemory { lhsMemory in
+        rhs.withUnsafeMemory { rhsMemory in
+            cblas_daxpy(elementCount, alpha, rhsMemory.pointer, numericCast(rhsMemory.stride), lhsMemory.pointer, numericCast(lhsMemory.stride))
+        }
+    }
+}
+
 // MARK: - Multiplication
 
 public func mul<L: UnsafeMemoryAccessible>(_ lhs: L, _ rhs: Float) -> [Float] where L.Element == Float {