Merge reviewed explicit constant-zero derivative seeds

src/fesa/elements/nonlinear_mitc4_shell.cpp

@@ -859,9 +859,17 @@ JetVector3 Cross(const JetVector3& left, const JetVector3& right) {
           left[0U] * right[1U] - left[1U] * right[0U]};
 }
 
+/// @brief Seeds only explicitly zero matrix entries with constant provenance.
+JetMatrix3 ConstantZeroMatrix() {
+  JetMatrix3 result{};
+  for (auto& row : result)
+    for (auto& entry : row) entry = Constant(0.0);
+  return result;
+}
+
 /// @brief Builds a Jet identity matrix.
 JetMatrix3 Identity() {
-  JetMatrix3 result{};
+  JetMatrix3 result = ConstantZeroMatrix();
   for (std::size_t index = 0U; index < 3U; ++index) {
     result[index][index] = Constant(1.0);
   }
@@ -870,7 +878,7 @@ JetMatrix3 Identity() {
 
 /// @brief Forms a skew matrix from a Jet vector.
 JetMatrix3 Skew(const JetVector3& value) {
-  JetMatrix3 result{};
+  JetMatrix3 result = ConstantZeroMatrix();
   result[0U][1U] = -1.0 * value[2U];
   result[0U][2U] = value[1U];
   result[1U][0U] = value[2U];
@@ -882,7 +890,7 @@ JetMatrix3 Skew(const JetVector3& value) {
 
 /// @brief Multiplies two three-by-three Jet matrices.
 JetMatrix3 Multiply(const JetMatrix3& left, const JetMatrix3& right) {
-  JetMatrix3 result{};
+  JetMatrix3 result = ConstantZeroMatrix();
   for (std::size_t row = 0U; row < 3U; ++row) {
     for (std::size_t column = 0U; column < 3U; ++column) {
       for (std::size_t index = 0U; index < 3U; ++index) {
@@ -896,7 +904,7 @@ JetMatrix3 Multiply(const JetMatrix3& left, const JetMatrix3& right) {
 
 /// @brief Multiplies a Jet matrix by a Jet vector.
 JetVector3 Multiply(const JetMatrix3& matrix, const JetVector3& vector) {
-  JetVector3 result{};
+  JetVector3 result{Constant(0.0), Constant(0.0), Constant(0.0)};
   for (std::size_t row = 0U; row < 3U; ++row) {
     for (std::size_t column = 0U; column < 3U; ++column) {
       result[row] = result[row] + matrix[row][column] * vector[column];