AnalogTapeModel

commit 14c63c416367535e63a70d24a0adca23a712b4f8
parent f382931d34fddb5a8d28c50e842f9343f0b2d42b
Author: jatinchowdhury18 <jatinchowdhury18@gmail.com>
Date:   Tue, 18 Aug 2020 10:36:10 -0700

Adjustments to Newton-Raphson solver (#72)

Co-authored-by: jatinchowdhury18 <jatinchowdhury18@users.noreply.github.com>
Diffstat:
M
CHANGELOG.md
 | 
2
+-
M
Plugin/Bench/Source/Main.cpp
 | 
2
+-
M
Plugin/Source/GUI/Assets/gui.xml
 | 
2
+-
M
Plugin/Source/Processors/Hysteresis/HysteresisProcessing.cpp
 | 
16
+++++-----------
M
Plugin/Source/Processors/Hysteresis/HysteresisProcessing.h
 | 
4
++--
M
Plugin/Source/Processors/Hysteresis/HysteresisProcessor.cpp
 | 
2
+-

6 files changed, 11 insertions(+), 17 deletions(-)
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,7 +5,7 @@ this file.
 ## [UNRELEASED]
 - Updated delay lines in wow/flutter processing to use 3-point
   Lagrange interpolation.
-- Improved Newton-Raphson solver performance.
+- Change Newton-Raphson solver to use 4 or 8 iterations, in unrolled loop.
 - Improved loss filter sliders.
 - Fixed tooltip name sometimes not appearing.
 - Fixed save/load bug for VST3 in Ableton.
diff --git a/Plugin/Bench/Source/Main.cpp b/Plugin/Bench/Source/Main.cpp
@@ -44,7 +44,7 @@ int main (int argc, char* argv[])
             param->setValue (3.0f / 4.0f); // 8x
 
         if (param->getName (10) == "Mode")
-            param->setValue (3.0f / 5.0f); // NR5
+            param->setValue (3.0f / 5.0f); // NR4
     }
 
     // process audio
diff --git a/Plugin/Source/GUI/Assets/gui.xml b/Plugin/Source/GUI/Assets/gui.xml
@@ -128,7 +128,7 @@
       <ComboBox lookAndFeel="ComboBoxLNF" padding="0" border="0" background-color="00000000"
                 name="Hysteresis Mode" caption="Hysteresis Mode" caption-size="0"
                 combo-text="FFEAA92C" caption-color="FFFFFFFF" max-height="100"
-                margin="" parameter="mode" combo-background="00000000" tooltip="Selects the mode to use for hysteresis processing. Choose between 2nd/4th order Runge-Kutta method, 5 or 10 Newton-Raphson iterations, or revert to version 1.0."/>
+                margin="" parameter="mode" combo-background="00000000" tooltip="Selects the mode to use for hysteresis processing. Choose between 2nd/4th order Runge-Kutta method, 4 or 8 Newton-Raphson iterations, or revert to version 1.0."/>
       <presets margin="5" padding="0" background-color="00000000" border-color="595C6B"
                radius="" border="" lookAndFeel="ComboBoxLNF" tooltip="Selects a preset for the plugin."
                flex-grow="1.8" max-height="100"/>
diff --git a/Plugin/Source/Processors/Hysteresis/HysteresisProcessing.cpp b/Plugin/Source/Processors/Hysteresis/HysteresisProcessing.cpp
@@ -72,12 +72,12 @@ void HysteresisProcessing::setSolver (SolverType solverType)
         solver = &HysteresisProcessing::RK4;
         return;
 
-    case SolverType::NR5:
-        numIter = 5;
+    case SolverType::NR4:
+        numIter = 4;
         return;
 
-    case SolverType::NR10:
-        numIter = 10;
+    case SolverType::NR8:
+        numIter = 8;
         return;
 
     default: // RK2
@@ -170,7 +170,7 @@ inline double HysteresisProcessing::NR (double H, double H_d) noexcept
     const double last_dMdt = hysteresisFunc (M_n1, H_n1, H_d_n1);
 
     double dMdt, dMdtPrime, deltaNR;
-    for (int n = 0; n < numIter; n += 5)
+    for (int n = 0; n < numIter; n += 4)
     {
         // loop #1
         dMdt = hysteresisFunc (M, H, H_d);
@@ -195,12 +195,6 @@ inline double HysteresisProcessing::NR (double H, double H_d) noexcept
         dMdtPrime = hysteresisFuncPrime (H_d, dMdt);
         deltaNR = (M - M_n1 - Talpha * (dMdt + last_dMdt)) / (1.0 - Talpha * dMdtPrime);
         M -= deltaNR;
-
-        // loop #5
-        dMdt = hysteresisFunc (M, H, H_d);
-        dMdtPrime = hysteresisFuncPrime (H_d, dMdt);
-        deltaNR = (M - M_n1 - Talpha * (dMdt + last_dMdt)) / (1.0 - Talpha * dMdtPrime);
-        M -= deltaNR;
     }
 
     return M;
diff --git a/Plugin/Source/Processors/Hysteresis/HysteresisProcessing.h b/Plugin/Source/Processors/Hysteresis/HysteresisProcessing.h
@@ -7,8 +7,8 @@ enum SolverType
 {
     RK2 = 0,
     RK4,
-    NR5,
-    NR10,
+    NR4,
+    NR8,
 };
 
 /*
diff --git a/Plugin/Source/Processors/Hysteresis/HysteresisProcessor.cpp b/Plugin/Source/Processors/Hysteresis/HysteresisProcessor.cpp
@@ -32,7 +32,7 @@ void HysteresisProcessor::createParameterLayout (std::vector<std::unique_ptr<Ran
     params.push_back (std::make_unique<AudioParameterFloat> ("sat", "Saturation", 0.0f, 1.0f, 0.5f));
     params.push_back (std::make_unique<AudioParameterFloat> ("width", "Bias", 0.0f, 1.0f, 0.5f));
 
-    params.push_back (std::make_unique<AudioParameterChoice> ("mode", "Mode", StringArray ({"RK2", "RK4", "NR5", "NR10", "V1"}), 0));
+    params.push_back (std::make_unique<AudioParameterChoice> ("mode", "Mode", StringArray ({"RK2", "RK4", "NR4", "NR8", "V1"}), 0));
     params.push_back (std::make_unique<AudioParameterChoice> ("os", "Oversampling", StringArray ({"1x", "2x", "4x", "8x", "16x"}), 1));
 }