From 7a3c85e47346af7765c23c8855b032f6c0bcdedb Mon Sep 17 00:00:00 2001
From: jatin <jatinchowdhury18@gmail.com>
Date: Thu, 30 Nov 2023 22:57:56 -0800
Subject: [PATCH] Allow for users to provide their own Omega function
 implementation

---
 CMakeLists.txt                                 | 2 +-
 include/chowdsp_wdf/math/omega.h               | 8 ++++++++
 include/chowdsp_wdf/wdft/wdft_nonlinearities.h | 8 ++++----
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3acb03d..b964e10 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.5)
 project(chowdsp_wdf VERSION 1.0.0 LANGUAGES C CXX)
 include(cmake/CXXStandard.cmake)
 
diff --git a/include/chowdsp_wdf/math/omega.h b/include/chowdsp_wdf/math/omega.h
index 5ecb4cf..f29c170 100644
--- a/include/chowdsp_wdf/math/omega.h
+++ b/include/chowdsp_wdf/math/omega.h
@@ -323,6 +323,14 @@ namespace Omega
         return y - (y - exp_approx<T> (x - y)) / (y + (T) 1);
     }
 
+    struct Omega
+    {
+        template <typename T>
+        static T omega (T x)
+        {
+            return omega4 (x);
+        }
+    };
 } // namespace Omega
 } // namespace chowdsp
 
diff --git a/include/chowdsp_wdf/wdft/wdft_nonlinearities.h b/include/chowdsp_wdf/wdft/wdft_nonlinearities.h
index 29c443f..c7a2176 100644
--- a/include/chowdsp_wdf/wdft/wdft_nonlinearities.h
+++ b/include/chowdsp_wdf/wdft/wdft_nonlinearities.h
@@ -24,7 +24,7 @@ namespace wdft
      * See Werner et al., "An Improved and Generalized Diode Clipper Model for Wave Digital Filters"
      * https://www.researchgate.net/publication/299514713_An_Improved_and_Generalized_Diode_Clipper_Model_for_Wave_Digital_Filters
      */
-    template <typename T, typename Next, DiodeQuality Quality = DiodeQuality::Best>
+    template <typename T, typename Next, DiodeQuality Quality = DiodeQuality::Best, typename OmegaProvider = Omega::Omega>
     class DiodePairT final : public RootWDF
     {
     public:
@@ -86,7 +86,7 @@ namespace wdft
         {
             // See eqn (18) from reference paper
             T lambda = (T) signum::signum (wdf.a);
-            wdf.b = wdf.a + (T) 2 * lambda * (R_Is - Vt * Omega::omega4 (logR_Is_overVt + lambda * wdf.a * oneOverVt + R_Is_overVt));
+            wdf.b = wdf.a + (T) 2 * lambda * (R_Is - Vt * OmegaProvider::omega (logR_Is_overVt + lambda * wdf.a * oneOverVt + R_Is_overVt));
         }
 
         /** Implementation for float/double (Best). */
@@ -118,7 +118,7 @@ namespace wdft
      * See Werner et al., "An Improved and Generalized Diode Clipper Model for Wave Digital Filters"
      * https://www.researchgate.net/publication/299514713_An_Improved_and_Generalized_Diode_Clipper_Model_for_Wave_Digital_Filters
      */
-    template <typename T, typename Next, DiodeQuality Quality = DiodeQuality::Best>
+    template <typename T, typename Next, DiodeQuality Quality = DiodeQuality::Best, typename OmegaProvider = Omega::Omega>
     class DiodeT final : public RootWDF
     {
     public:
@@ -167,7 +167,7 @@ namespace wdft
         inline T reflected() noexcept
         {
             // See eqn (10) from reference paper
-            wdf.b = wdf.a + twoR_Is - twoVt * Omega::omega4 (logR_Is_overVt + wdf.a * oneOverVt + R_Is_overVt);
+            wdf.b = wdf.a + twoR_Is - twoVt * OmegaProvider::omega (logR_Is_overVt + wdf.a * oneOverVt + R_Is_overVt);
             return wdf.b;
         }