remove reinterpret_cast in rhs.H (#1435)

Author: zingale

networks/rhs.H

@@ -273,19 +273,17 @@ constexpr int is_jacobian_term_used ()
 }
 
 AMREX_GPU_HOST_DEVICE AMREX_INLINE
-void dgesl (RArray2D& a1, RArray1D& b1)
+void dgesl (const RArray2D& a, RArray1D& b)
 {
-    auto const& a = reinterpret_cast<amrex::Array2D<amrex::Real, 0, INT_NEQS-1, 0, INT_NEQS-1>&>(a1);
-    auto& b = reinterpret_cast<amrex::Array1D<amrex::Real, 0, INT_NEQS-1>&>(b1);
 
     // solve a * x = b
     // first solve l * y = b
-    constexpr_for<0, INT_NEQS-1>([&] (auto n1)
+    constexpr_for<1, INT_NEQS>([&] (auto n1)
     {
         constexpr int k = n1;
 
         amrex::Real t = b(k);
-        constexpr_for<k+1, INT_NEQS>([&] (auto n2)
+        constexpr_for<k+1, INT_NEQS+1>([&] (auto n2)
         {
             constexpr int j = n2;
 
@@ -294,47 +292,47 @@ void dgesl (RArray2D& a1, RArray1D& b1)
     });
 
     // now solve u * x = y
-    constexpr_for<0, INT_NEQS>([&] (auto kb)
+    constexpr_for<1, INT_NEQS+1>([&] (auto kb)
     {
-        constexpr int k = INT_NEQS - kb - 1;
+        constexpr int k = INT_NEQS + 1 - kb;
 
         b(k) = b(k) / a(k,k);
         amrex::Real t = -b(k);
 
-        constexpr_for<0, k>([&] (auto j)
+        constexpr_for<1, k>([&] (auto j)
         {
             b(j) += t * a(j,k);
         });
     });
 }
 
 AMREX_GPU_HOST_DEVICE AMREX_INLINE
-void dgefa (RArray2D& a1)
+void dgefa (RArray2D& a)
 {
-    auto& a = reinterpret_cast<amrex::Array2D<amrex::Real, 0, INT_NEQS-1, 0, INT_NEQS-1>&>(a1);
 
     // LU factorization in-place without pivoting.
 
-    constexpr_for<0, INT_NEQS-1>([&] (auto n1)
+    constexpr_for<1, INT_NEQS>([&] (auto n1)
     {
         [[maybe_unused]] constexpr int k = n1;
 
         // compute multipliers
+
         amrex::Real t = -1.0_rt / a(k,k);
-        constexpr_for<k+1, INT_NEQS>([&] (auto n2)
+        constexpr_for<k+1, INT_NEQS+1>([&] (auto n2)
         {
             [[maybe_unused]] constexpr int j = n2;
 
             a(j,k) *= t;
         });
 
         // row elimination with column indexing
-        constexpr_for<k+1, INT_NEQS>([&] (auto n2)
+        constexpr_for<k+1, INT_NEQS+1>([&] (auto n2)
         {
             [[maybe_unused]] constexpr int j = n2;
 
             t = a(k,j);
-            constexpr_for<k+1, INT_NEQS>([&] (auto n3)
+            constexpr_for<k+1, INT_NEQS+1>([&] (auto n3)
             {
                 [[maybe_unused]] constexpr int i = n3;