From d1b821f84a493925a7785af273ceb4a565e6813d Mon Sep 17 00:00:00 2001
From: Frederick Roy <froy@lnrobo.com>
Date: Thu, 8 Sep 2022 10:40:57 +0900
Subject: [PATCH 1/3] mat: std abs only constexpr in c++23

---
 Sofa/framework/Type/src/sofa/type/Mat.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Sofa/framework/Type/src/sofa/type/Mat.h b/Sofa/framework/Type/src/sofa/type/Mat.h
index 320c2a0eb7d..87d7f9e71b7 100644
--- a/Sofa/framework/Type/src/sofa/type/Mat.h
+++ b/Sofa/framework/Type/src/sofa/type/Mat.h
@@ -28,6 +28,7 @@
 #include <sofa/type/Vec.h>
 
 #include <iostream>
+#include <type_traits>
 
 namespace // anonymous
 {
@@ -35,7 +36,7 @@ namespace // anonymous
     constexpr real rabs(const real r)
     {
         if constexpr (std::is_signed<real>())
-            return std::abs(r);
+            return r < 0 ? -r : r;
         else
             return r;
     }

From e2e637c56a1fef3fb3fa56fa4e05749a376ce248 Mon Sep 17 00:00:00 2001
From: Frederick Roy <froy@lnrobo.com>
Date: Thu, 8 Sep 2022 10:54:33 +0900
Subject: [PATCH 2/3] sqrt is not constexpr in std

---
 Sofa/framework/Type/src/sofa/type/Mat.h |  1 -
 Sofa/framework/Type/src/sofa/type/Vec.h | 12 ++++++------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/Sofa/framework/Type/src/sofa/type/Mat.h b/Sofa/framework/Type/src/sofa/type/Mat.h
index 87d7f9e71b7..149a99eb6ac 100644
--- a/Sofa/framework/Type/src/sofa/type/Mat.h
+++ b/Sofa/framework/Type/src/sofa/type/Mat.h
@@ -28,7 +28,6 @@
 #include <sofa/type/Vec.h>
 
 #include <iostream>
-#include <type_traits>
 
 namespace // anonymous
 {
diff --git a/Sofa/framework/Type/src/sofa/type/Vec.h b/Sofa/framework/Type/src/sofa/type/Vec.h
index e36a44a464d..37befa51805 100644
--- a/Sofa/framework/Type/src/sofa/type/Vec.h
+++ b/Sofa/framework/Type/src/sofa/type/Vec.h
@@ -42,7 +42,7 @@ namespace // anonymous
     constexpr real rabs(const real r)
     {
         if constexpr (std::is_signed<real>())
-            return std::abs(r);
+            return r < 0 ? -r : r;
         else
             return r;
     }
@@ -441,7 +441,7 @@ class Vec : public sofa::type::fixed_array<ValueType,size_t(N)>
     }
 
     /// Euclidean norm.
-    constexpr ValueType norm() const noexcept
+    ValueType norm() const noexcept
     {
         return ValueType(std::sqrt(norm2()));
     }
@@ -449,7 +449,7 @@ class Vec : public sofa::type::fixed_array<ValueType,size_t(N)>
     /// l-norm of the vector
     /// The type of norm is set by parameter l.
     /// Use l<0 for the infinite norm.
-    constexpr ValueType lNorm( int l ) const
+    ValueType lNorm( int l ) const
     {
         if( l==2 ) return norm(); // euclidian norm
         else if( l<0 ) // infinite norm
@@ -504,21 +504,21 @@ class Vec : public sofa::type::fixed_array<ValueType,size_t(N)>
 
     /// Normalize the vector.
     /// returns false iff the norm is too small
-    constexpr bool normalize(ValueType threshold=std::numeric_limits<ValueType>::epsilon()) noexcept
+    bool normalize(ValueType threshold=std::numeric_limits<ValueType>::epsilon()) noexcept
     {
         return normalizeWithNorm(norm(),threshold);
     }
 
     /// Normalize the vector with a failsafe.
     /// If the norm is too small, the vector becomes the failsafe.
-    constexpr void normalize(Vec<N,ValueType> failsafe, ValueType threshold=std::numeric_limits<ValueType>::epsilon()) noexcept
+    void normalize(Vec<N,ValueType> failsafe, ValueType threshold=std::numeric_limits<ValueType>::epsilon()) noexcept
     {
         if( !normalize(threshold) ) *this=failsafe;
     }
 
     /// Return the normalized vector.
     /// @warning 'this' is not normalized.
-    constexpr Vec<N,ValueType> normalized() const noexcept
+    Vec<N,ValueType> normalized() const noexcept
     {
         Vec<N,ValueType> r(*this);
         r.normalize();

From 7b55fef90ab393d587209b7b80d8400051d04542 Mon Sep 17 00:00:00 2001
From: Frederick Roy <froy@lnrobo.com>
Date: Tue, 13 Sep 2022 10:02:15 +0900
Subject: [PATCH 3/3] make rabs non-constexpr as std::abs is not constexpr

---
 Sofa/framework/Type/src/sofa/type/Mat.h | 20 ++++++++++----------
 Sofa/framework/Type/src/sofa/type/Vec.h |  6 +++---
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/Sofa/framework/Type/src/sofa/type/Mat.h b/Sofa/framework/Type/src/sofa/type/Mat.h
index 149a99eb6ac..be6a3befa12 100644
--- a/Sofa/framework/Type/src/sofa/type/Mat.h
+++ b/Sofa/framework/Type/src/sofa/type/Mat.h
@@ -32,16 +32,16 @@
 namespace // anonymous
 {
     template<typename real>
-    constexpr real rabs(const real r)
+    real rabs(const real r)
     {
         if constexpr (std::is_signed<real>())
-            return r < 0 ? -r : r;
+            return std::abs(r);
         else
             return r;
     }
 
     template<typename real>
-    constexpr real equalsZero(const real r, const real epsilon = std::numeric_limits<real>::epsilon())
+    real equalsZero(const real r, const real epsilon = std::numeric_limits<real>::epsilon())
     {
         return rabs(r) <= epsilon;
     }
@@ -65,8 +65,8 @@ class Mat : public fixed_array<VecNoInit<C,real>, L>
     typedef VecNoInit<C,real> LineNoInit;
     typedef Vec<L,real> Col;
 
-    static const Size nbLines = L;
-    static const Size nbCols  = C;
+    static constexpr Size nbLines = L;
+    static constexpr Size nbCols  = C;
 
     constexpr Mat() noexcept
     {
@@ -389,7 +389,7 @@ class Mat : public fixed_array<VecNoInit<C,real>, L>
     }
 
 
-    constexpr bool isSymmetric() const
+    bool isSymmetric() const
     {
         for (Size i=0; i<L; i++)
             for (Size j=i+1; j<C; j++)
@@ -397,7 +397,7 @@ class Mat : public fixed_array<VecNoInit<C,real>, L>
         return true;
     }
 
-    constexpr bool isDiagonal() const noexcept
+    bool isDiagonal() const noexcept
     {
         for (Size i=0; i<L; i++)
         {
@@ -799,7 +799,7 @@ constexpr real determinant(const Mat<3,2,real>& m) noexcept
 
 // one-norm of a 3 x 3 matrix
 template<class real>
-constexpr real oneNorm(const Mat<3,3,real>& A)
+real oneNorm(const Mat<3,3,real>& A)
 {
     real norm = 0.0;
     for (sofa::Size i=0; i<3; i++)
@@ -813,7 +813,7 @@ constexpr real oneNorm(const Mat<3,3,real>& A)
 
 // inf-norm of a 3 x 3 matrix
 template<class real>
-constexpr real infNorm(const Mat<3,3,real>& A)
+real infNorm(const Mat<3,3,real>& A)
 {
     real norm = 0.0;
     for (sofa::Size i=0; i<3; i++)
@@ -847,7 +847,7 @@ constexpr Vec<N,real> diagonal(const Mat<N,N,real>& m)
 
 /// Matrix inversion (general case).
 template<sofa::Size S, class real>
-[[nodiscard]] constexpr bool invertMatrix(Mat<S,S,real>& dest, const Mat<S,S,real>& from)
+[[nodiscard]] bool invertMatrix(Mat<S,S,real>& dest, const Mat<S,S,real>& from)
 {
     sofa::Size i{0}, j{0}, k{0};
     Vec<S, sofa::Size> r, c, row, col;
diff --git a/Sofa/framework/Type/src/sofa/type/Vec.h b/Sofa/framework/Type/src/sofa/type/Vec.h
index 37befa51805..e090a3d5e8f 100644
--- a/Sofa/framework/Type/src/sofa/type/Vec.h
+++ b/Sofa/framework/Type/src/sofa/type/Vec.h
@@ -39,10 +39,10 @@ namespace sofa::type
 namespace // anonymous
 {
     template<typename real>
-    constexpr real rabs(const real r)
+    real rabs(const real r)
     {
         if constexpr (std::is_signed<real>())
-            return r < 0 ? -r : r;
+            return std::abs(r);
         else
             return r;
     }
@@ -526,7 +526,7 @@ class Vec : public sofa::type::fixed_array<ValueType,size_t(N)>
     }
 
     /// return true if norm()==1
-    constexpr bool isNormalized( ValueType threshold=std::numeric_limits<ValueType>::epsilon()*(ValueType)10 ) const
+    bool isNormalized( ValueType threshold=std::numeric_limits<ValueType>::epsilon()*(ValueType)10 ) const
     { 
         return rabs( norm2() - static_cast<ValueType>(1) ) <= threshold;
     }