From e1748828adb21bedcd35fc1c0311260eec0f0499 Mon Sep 17 00:00:00 2001
From: Ingmar Schoegl <ischoegl@lsu.edu>
Date: Fri, 23 Jun 2023 15:31:26 -0600
Subject: [PATCH] [Func1] Refactor derivative rules

---
 include/cantera/numerics/Func1.h | 41 ++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/include/cantera/numerics/Func1.h b/include/cantera/numerics/Func1.h
index 1916992666..7047d6b550 100644
--- a/include/cantera/numerics/Func1.h
+++ b/include/cantera/numerics/Func1.h
@@ -478,6 +478,11 @@ class Sum1 : public Func1
         Func1& d2 = m_f2->derivative();
         return newSumFunction(d1, d2);
     }
+
+    virtual shared_ptr<Func1> derivative3() const {
+        return newSumFunction(m_f1_shared->derivative3(), m_f2_shared->derivative3());
+    }
+
     virtual int order() const {
         return 0;
     }
@@ -544,6 +549,11 @@ class Diff1 : public Func1
     virtual Func1& derivative() const {
         return newDiffFunction(m_f1->derivative(), m_f2->derivative());
     }
+
+    virtual shared_ptr<Func1> derivative3() const {
+        return newDiffFunction(m_f1_shared->derivative3(), m_f2_shared->derivative3());
+    }
+
     virtual int order() const {
         return 0;
     }
@@ -615,6 +625,13 @@ class Product1 : public Func1
         Func1& a2 = newProdFunction(m_f2->duplicate(), m_f1->derivative());
         return newSumFunction(a1, a2);
     }
+
+    virtual shared_ptr<Func1> derivative3() const {
+        auto a1 = newProdFunction(m_f1_shared, m_f2_shared->derivative3());
+        auto a2 = newProdFunction(m_f2_shared, m_f1_shared->derivative3());
+        return newSumFunction(a1, a2);
+    }
+
     virtual int order() const {
         return 1;
     }
@@ -691,6 +708,10 @@ class TimesConstant1 : public Func1
         return *d;
     }
 
+    virtual shared_ptr<Func1> derivative3() const {
+        return newTimesConstFunction(m_f1_shared->derivative3(), m_c);
+    }
+
     virtual std::string write(const std::string& arg) const;
 
     virtual int order() const {
@@ -750,6 +771,11 @@ class PlusConstant1 : public Func1
     virtual Func1& derivative() const {
         return m_f1->derivative();
     }
+
+    virtual shared_ptr<Func1> derivative3() const {
+        return m_f1_shared->derivative3();
+    }
+
     virtual std::string write(const std::string& arg) const;
 
     virtual int order() const {
@@ -822,6 +848,14 @@ class Ratio1 : public Func1
         return newRatioFunction(s, p);
     }
 
+    virtual shared_ptr<Func1> derivative3() const {
+        auto a1 = newProdFunction(m_f1_shared->derivative3(), m_f2_shared);
+        auto a2 = newProdFunction(m_f1_shared, m_f2_shared->derivative3());
+        auto s = newDiffFunction(a1, a2);
+        auto p = newProdFunction(m_f2_shared, m_f2_shared);
+        return newRatioFunction(s, p);
+    }
+
     virtual std::string write(const std::string& arg) const;
 
     virtual int order() const {
@@ -894,6 +928,13 @@ class Composite1 : public Func1
         return *p;
     }
 
+    virtual shared_ptr<Func1> derivative3() const {
+        auto d1 = m_f1_shared->derivative3();
+        auto d2 = m_f2_shared->derivative3();
+        auto d3 = newCompositeFunction(d1, m_f2_shared);
+        return newProdFunction(d3, d2);
+    }
+
     virtual std::string write(const std::string& arg) const;
 
     virtual int order() const {