Alternate fix for diffusion_1

Signed-off-by: Steven Hahn <[email protected]>

src/pde/pde_base.hpp

@@ -549,7 +549,7 @@ class PDE
       // each set of analytical solution functions must have num_dim functions
       for (const auto &md_func : exact_vector_funcs)
       {
-        expect(md_func.size() == static_cast<unsigned>(num_dims));
+        expect(std::clamp(md_func.size(), static_cast<size_t>(num_dims), static_cast<size_t>(num_dims) + 1u) == md_func.size());
       }
     }
 

src/pde/pde_diffusion1.hpp

@@ -151,17 +151,22 @@ class PDE_diffusion_1d : public PDE<P>
   /* exact solutions */
   static fk::vector<P> exact_solution_0(fk::vector<P> const x, P const t = 0)
   {
+    ignore(t);
     fk::vector<P> fx(x.size());
-    P const time = source_0_t(t);
     std::transform(x.begin(), x.end(), fx.begin(),
-                   [time](P const &x_v) { return std::cos(nu * x_v) * time; });
+                   [](P const &x_v) { return std::cos(nu * x_v); });
     return fx;
   }
 
-  static P exact_time(P const time) { return source_0_t(time); }
+  static fk::vector<P> exact_time(fk::vector<P> x, P const time)
+  {
+    x.resize(1);
+    x[0] = source_0_t(time);
+    return x;
+  }
 
   inline static std::vector<vector_func<P>> const exact_vector_funcs_ = {
-      exact_solution_0};
+      exact_solution_0, exact_time};
 
   /* This is not used ever */
   inline static scalar_func<P> const exact_scalar_func_ = source_0_t;

src/transformations.hpp

@@ -242,7 +242,7 @@ inline void transform_and_combine_dimensions(
     P const time_multiplier, fk::vector<P, mem_type::view> result)
 
 {
-  expect(v_functions.size() == dims.size());
+  expect(std::clamp(v_functions.size(), dims.size(), dims.size() + 1u) == v_functions.size());
   expect(start <= stop);
   expect(stop < table.size());
   expect(degree >= 0);