llnl · btalamini · Mar 12, 2026 · Mar 13, 2026 · Mar 13, 2026 · Mar 14, 2026
diff --git a/.gitignore b/.gitignore
@@ -29,3 +29,7 @@ AGENTS.md
 agents.md
 CLAUDE.md
 claude.md
+*plan.md
+slirp.out
+*~
+*#
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -81,7 +81,9 @@ endif()
 
 # Tune BLT to our needs
 if (NOT BLT_CXX_STD)
-    set(BLT_CXX_STD "c++17" CACHE STRING "")
+    set(BLT_CXX_STD "c++20" CACHE STRING "")
+elseif (BLT_CXX_STD MATCHES "^c\\+\\+([0-9]+)$" AND CMAKE_MATCH_1 VERSION_LESS 20)
+    message(FATAL_ERROR "Smith requires BLT_CXX_STD to be c++20 or higher.")
 endif()
 
 # These BLT tools are not used in Smith, turn them off

diff --git a/cmake/SmithCompilerFlags.cmake b/cmake/SmithCompilerFlags.cmake
@@ -14,6 +14,36 @@ endif()
 # Need to add symbols to dynamic symtab in order to be visible from stacktraces
 string(APPEND CMAKE_EXE_LINKER_FLAGS " -rdynamic")
 
+# ROCm's amdclang++ can drop its implicit C++ standard library on HIP links
+# once Fortran runtime libraries are introduced. On this platform the shared
+# libstdc++ linker script still points at the old system runtime, so use the
+# compiler's GCC 13 static archives instead.
+if(SMITH_ENABLE_CODEVELOP AND 
+   ENABLE_HIP AND 
+   CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
+   CMAKE_CXX_COMPILER MATCHES "amdclang\\+\\+")
+    execute_process(
+        COMMAND ${CMAKE_CXX_COMPILER} -print-file-name=libstdc++.a
+        OUTPUT_VARIABLE _smith_libstdcxx_static
+        OUTPUT_STRIP_TRAILING_WHITESPACE)
+    execute_process(
+        COMMAND ${CMAKE_CXX_COMPILER} -print-file-name=libstdc++_nonshared.a
+        OUTPUT_VARIABLE _smith_libstdcxx_nonshared
+        OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+    if(EXISTS "${_smith_libstdcxx_static}" AND EXISTS "${_smith_libstdcxx_nonshared}")
+        string(APPEND CMAKE_CXX_STANDARD_LIBRARIES
+            " ${_smith_libstdcxx_static} ${_smith_libstdcxx_nonshared}")
+    endif()
+endif()
+
+# Apple ld warns about duplicate -l flags when the same library is reachable
+# via multiple dependency paths (common with Spack-built CMake targets that use
+# raw -l strings instead of imported targets). Suppress the spurious warning.
+if(APPLE)
+    string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wl,-no_warn_duplicate_libraries")
+endif()
+
 # Prevent unused -Xlinker arguments on Lassen Clang-10
 if(DEFINED ENV{SYS_TYPE} AND "$ENV{SYS_TYPE}" STREQUAL "blueos_3_ppc64le_ib_p9")
     string(APPEND CMAKE_EXE_LINKER_FLAGS " -Wno-unused-command-line-argument")
@@ -23,7 +53,6 @@ endif()
 set(_extra_flags "-Wshadow -Wdouble-promotion -Wconversion -Wundef -Wnull-dereference -Wold-style-cast")
 blt_append_custom_compiler_flag(FLAGS_VAR CMAKE_CXX_FLAGS DEFAULT ${_extra_flags})
 
-# Only clang has fine-grained control over the designated initializer warnings
-# This can be added to the GCC flags when C++20 is available
-# This should be compatible with Clang 8 through Clang 12
-blt_append_custom_compiler_flag(FLAGS_VAR CMAKE_CXX_FLAGS CLANG "-Wpedantic -Wno-c++2a-extensions -Wunused-private-field")
+# Clang specific warnings
+# Note: pedantic is a gcc flag but throws a false positive in src/smith/numerics/petsc_solvers.cpp
+blt_append_custom_compiler_flag(FLAGS_VAR CMAKE_CXX_FLAGS CLANG "-Wpedantic -Wunused-private-field")
diff --git a/cmake/thirdparty/FindMFEM.cmake b/cmake/thirdparty/FindMFEM.cmake
@@ -108,6 +108,11 @@ else()
         set(_mfem_tpl_list ${mfem_tpl_lnk_flags})
         separate_arguments(_mfem_tpl_list)
         list(FILTER _mfem_tpl_list EXCLUDE REGEX Xlinker)
+        # On Apple, -Wl,-rpath,... entries duplicate CMake's own rpath management
+        # (CMAKE_INSTALL_RPATH_USE_LINK_PATH) and cause ld "duplicate -rpath" warnings
+        if(APPLE)
+            list(FILTER _mfem_tpl_list EXCLUDE REGEX "^-Wl,-rpath,")
+        endif()
         list(JOIN _mfem_tpl_list " " mfem_tpl_lnk_flags)
     else()
         message(WARNING "No third party library flags found in ${MFEM_CFG_DIR}/config.mk")

diff --git a/cmake/thirdparty/SetupSmithThirdParty.cmake b/cmake/thirdparty/SetupSmithThirdParty.cmake
@@ -707,6 +707,22 @@ if (NOT SMITH_THIRD_PARTY_LIBRARIES_FOUND)
             endif()
         endforeach()
     endif()
+
+    # On Apple, Spack-built cmake configs embed literal -Wl,-rpath,... entries in
+    # INTERFACE_LINK_LIBRARIES. These duplicate CMake's own rpath management
+    # (CMAKE_INSTALL_RPATH_USE_LINK_PATH) and cause ld "duplicate -rpath" warnings.
+    if(APPLE)
+        foreach(_target ${_mfem_targets})
+            if(TARGET ${_target})
+                get_target_property(_link_libs ${_target} INTERFACE_LINK_LIBRARIES)
+                if(_link_libs)
+                    list(FILTER _link_libs EXCLUDE REGEX "^-Wl,-rpath,")
+                    set_target_properties(${_target} PROPERTIES INTERFACE_LINK_LIBRARIES "${_link_libs}")
+                endif()
+            endif()
+        endforeach()
+        unset(_link_libs)
+    endif()
     unset(_mfem_targets)
 
     # Restore cleared Adiak/Caliper directories, reason at top of file.

diff --git a/gretl b/gretl
diff --git a/src/docs/sphinx/build_guide/build_smith.rst b/src/docs/sphinx/build_guide/build_smith.rst
@@ -249,5 +249,18 @@ We provide the following useful build targets that can be run from the build dir
 * ``check``: Runs a set of code checks over source code (CppCheck and clang-format)
 * ``install``: Installs Smith into the previously given ``CMAKE_INSTALL_PREFIX`` directory
 
+MacOS Deployment Target Warning
+-------------------------------
 
+This section is for MacOS machines only.
 
+If you get the following warning(s) when building Smith...
+
+``ld: warning: object file (/spack_install_path/darwin-tahoe-aarch64/llvm-19.1.7/petsc-3.21.6-gg26icdjjmc5le6de6f5nviiqnhlanvj/lib/libpetsc.a[1377](slregis.o)) was built for newer 'macOS' version (26.0) than being linked (16.0)``
+
+...run the following command to add `MACOSX_DEPLOYMENT_TARGET` to your environment (the target version may be different
+for you):
+
+  .. code-block:: bash
+
+    echo "export MACOSX_DEPLOYMENT_TARGET=26.0" >> ~/.bash_profile
diff --git a/src/docs/sphinx/dev_guide/modern_cpp.rst b/src/docs/sphinx/dev_guide/modern_cpp.rst
@@ -7,7 +7,7 @@
 Frequently Used Modern C++ Features
 ===================================
 
-Smith currently uses C++17.  Several modern C++ features and library components are used heavily throughout Smith.
+Smith currently uses C++20.  Several modern C++ features and library components are used heavily throughout Smith.
 
 Smart pointers are used to avoid directly using ``operator new`` and ``operator delete`` except when absolutely necessary.
 ``std::unique_ptr<T>`` is used to denote **exclusive** ownership of a pointer to ``T`` - see `this article <https://www.drdobbs.com/cpp/c11-uniqueptr/240002708>`__ for more info.

diff --git a/src/smith/differentiable_numerics/differentiable_physics.cpp b/src/smith/differentiable_numerics/differentiable_physics.cpp
@@ -4,20 +4,13 @@
 //
 // SPDX-License-Identifier: (BSD-3-Clause)
 
-// Copyright (c) Lawrence Livermore National Security, LLC and
-// other Smith Project Developers. See the top-level LICENSE file for
-// details.
-//
-// SPDX-License-Identifier: (BSD-3-Clause)
-
 #include "gretl/data_store.hpp"
 #include "smith/differentiable_numerics/differentiable_physics.hpp"
 #include "smith/physics/weak_form.hpp"
 #include "smith/physics/mesh.hpp"
-#include "smith/differentiable_numerics/differentiable_physics.hpp"
 #include "smith/differentiable_numerics/state_advancer.hpp"
 #include "smith/differentiable_numerics/reaction.hpp"
-#include "gretl/data_store.hpp"
+#include "gretl/upstream_state.hpp"
 
 namespace smith {
 
@@ -248,7 +241,7 @@ void DifferentiablePhysics::reverseAdjointTimestep()
     current_step = checkpointer_->currentStep_;
   }
 
-  auto& upstreams = checkpointer_->upstreams_[milestone];
+  gretl::UpstreamStates upstreams(*checkpointer_, checkpointer_->upstreamSteps_[milestone]);
 
   SLIC_ERROR_IF(field_states_.size() != upstreams.size(), "field states and upstream sizes do not match.");
   // recreate the upstream field states with upstream step, field, and dual values.

diff --git a/src/smith/infrastructure/about.cpp b/src/smith/infrastructure/about.cpp
@@ -55,27 +55,26 @@ namespace smith {
 
 std::string about()
 {
-  using namespace axom::fmt;
   [[maybe_unused]] constexpr std::string_view on = "ON";
   [[maybe_unused]] constexpr std::string_view off = "OFF";
 
   std::string about = "\n";
 
   // Version info
-  about += format("Smith Version:    {0}\n", version());
+  about += axom::fmt::format("Smith Version:    {0}\n", version());
   about += "\n";
 
   // General configuration
 #ifdef SMITH_DEBUG
-  about += format("Debug Build:      {0}\n", on);
+  about += axom::fmt::format("Debug Build:      {0}\n", on);
 #else
-  about += format("Debug Build:      {0}\n", off);
+  about += axom::fmt::format("Debug Build:      {0}\n", off);
 #endif
 
 #ifdef SMITH_USE_CUDA
-  about += format("CUDA:             {0}\n", on);
+  about += axom::fmt::format("CUDA:             {0}\n", on);
 #else
-  about += format("CUDA:             {0}\n", off);
+  about += axom::fmt::format("CUDA:             {0}\n", off);
 #endif
 
   about += "\n";
@@ -91,21 +90,21 @@ std::string about()
   about += "Enabled Libraries:\n";
 
   // Axom
-  about += format("Axom Version:     {0}\n", axom::getVersion());
+  about += axom::fmt::format("Axom Version:     {0}\n", axom::getVersion());
 
   // Camp
-  about += format("Camp Version:     {0}\n", CAMP_VERSION);
+  about += axom::fmt::format("Camp Version:     {0}\n", CAMP_VERSION);
 
   // Caliper
 #ifdef SMITH_USE_CALIPER
-  about += format("Caliper Version:  {0}\n", CALIPER_VERSION);
+  about += axom::fmt::format("Caliper Version:  {0}\n", CALIPER_VERSION);
 #else
   disabled_libs.push_back("Caliper");
 #endif
 
   // Conduit
 #ifdef SMITH_USE_CONDUIT
-  about += format("Conduit Version:  {0}\n", CONDUIT_VERSION);
+  about += axom::fmt::format("Conduit Version:  {0}\n", CONDUIT_VERSION);
 #else
   disabled_libs.push_back("Conduit");
 #endif
@@ -117,9 +116,9 @@ std::string about()
   if (H5get_libversion(&h5_maj, &h5_min, &h5_rel) < 0) {
     SLIC_ERROR("Failed to retrieve HDF5 version.");
   } else {
-    h5_version = format("{0}.{1}.{2}", h5_maj, h5_min, h5_rel);
+    h5_version = axom::fmt::format("{0}.{1}.{2}", h5_maj, h5_min, h5_rel);
   }
-  about += format("HDF5 Version:     {0}\n", h5_version);
+  about += axom::fmt::format("HDF5 Version:     {0}\n", h5_version);
 #else
   disabled_libs.push_back("HDF5");
 #endif
@@ -130,7 +129,7 @@ std::string about()
   if (axom::utilities::string::startsWith(lua_version, "Lua ")) {
     lua_version.erase(0, 4);
   }
-  about += format("Lua Version:      {0}\n", lua_version);
+  about += axom::fmt::format("Lua Version:      {0}\n", lua_version);
 #else
   disabled_libs.push_back("Lua");
 #endif
@@ -149,28 +148,29 @@ std::string about()
     mfem_full_version.erase(0, 5);
   }
   if (mfem_sha[0] != '\0') {
-    mfem_full_version += format(" (Git SHA: {0})", mfem_sha);
+    mfem_full_version += axom::fmt::format(" (Git SHA: {0})", mfem_sha);
   }
-  about += format("MFEM Version:     {0}\n", mfem_full_version);
+  about += axom::fmt::format("MFEM Version:     {0}\n", mfem_full_version);
 
   // RAJA
 #ifdef SMITH_USE_RAJA
-  about += format("RAJA Version:     {0}.{1}.{2}\n", RAJA_VERSION_MAJOR, RAJA_VERSION_MINOR, RAJA_VERSION_PATCHLEVEL);
+  about += axom::fmt::format("RAJA Version:     {0}.{1}.{2}\n", RAJA_VERSION_MAJOR, RAJA_VERSION_MINOR,
+                             RAJA_VERSION_PATCHLEVEL);
 #else
   disabled_libs.push_back("RAJA");
 #endif
 
   // Tribol
 #ifdef SMITH_USE_TRIBOL
-  about += format("Tribol Version:     {0}\n", TRIBOL_VERSION_FULL);
+  about += axom::fmt::format("Tribol Version:     {0}\n", TRIBOL_VERSION_FULL);
 #else
   disabled_libs.push_back("Tribol");
 #endif
 
   // Umpire
 #ifdef SMITH_USE_UMPIRE
-  about += format("Umpire Version:   {0}.{1}.{2}\n", umpire::get_major_version(), umpire::get_minor_version(),
-                  umpire::get_patch_version());
+  about += axom::fmt::format("Umpire Version:   {0}.{1}.{2}\n", umpire::get_major_version(),
+                             umpire::get_minor_version(), umpire::get_patch_version());
 #else
   disabled_libs.push_back("Umpire");
 #endif

diff --git a/src/smith/numerics/equation_solver.cpp b/src/smith/numerics/equation_solver.cpp
@@ -99,6 +99,7 @@ class NewtonSolver : public mfem::NewtonSolver {
 
     real_t norm, norm_goal = 0;
     norm = initial_norm = evaluateNorm(x, r);
+    if (norm == 0.0) return;
 
     if (print_level == 1) {
       mfem::out << "Newton iteration " << std::setw(3) << 0 << " : ||r|| = " << std::setw(13) << norm << "\n";
@@ -648,6 +649,8 @@ class TrustRegion : public mfem::NewtonSolver {
 
     real_t norm, norm_goal = 0.0;
     norm = initial_norm = computeResidual(X, r);
+    if (norm == 0.0) return;
+
     norm_goal = std::max(rel_tol * initial_norm, abs_tol);
 
     if (print_level == 1) {

diff --git a/src/smith/numerics/functional/tests/test_newton.cpp b/src/smith/numerics/functional/tests/test_newton.cpp
@@ -99,10 +99,10 @@ TEST(ScalarEquationSolver, ReturnsImmediatelyIfLowerBoundIsARoot)
 
 TEST(ScalarEquationSolver, ConvergesWithGuessOutsideNewtonBasin)
 {
-  double x0 = 9.5;
+  double x0 = 2.0;
   double lower = -10.0;
   double upper = 10.0;
-  auto nasty_function = [](auto x) { return sin(x) + x; };
+  auto nasty_function = [](auto x) { return x/(1.0 + x*x); };
   auto [x, status] = solve_scalar_equation(nasty_function, x0, lower, upper, default_solver_options);
   double error = std::abs(x);
   EXPECT_LT(error, default_solver_options.xtol);

diff --git a/src/smith/numerics/functional/tuple_tensor_dual_functions.hpp b/src/smith/numerics/functional/tuple_tensor_dual_functions.hpp
@@ -604,6 +604,7 @@ auto solve_scalar_equation(const function& f, double x0, double lower_bound, dou
     if (fl > 0) {
       xl = upper_bound;
       xh = lower_bound;
+      // no need to update fl and fh, they're not used any more
     }
 
     // move initial guess if it is not between brackets
@@ -1056,4 +1057,24 @@ auto sqrt_symm(tensor<T, 3, 3> A)
   return symmetric_mat3_function(A, [](double x) { return std::sqrt(x); }, g);
 }
 
+/**
+ * @brief Logarithm of a symmetric matrix plus identity
+ *
+ * @param A Matrix to operate on. Must be SPD. This is not checked.
+ * @return log(A + I) \p.
+ */
+template <typename T>
+auto logIp_symm(tensor<T, 3, 3> A)
+{
+  auto g = [](double lam1, double lam2) {
+    if (lam1 == lam2) {
+      return 1 / (lam1 + 1.0);
+    } else {
+      double y = (1.0 + lam1) / (1.0 + lam2);
+      return (std::log(y) / (y - 1.0)) / (1.0 + lam2);
+    }
+  };
+  return symmetric_mat3_function(A, [](double x) { return std::log1p(x); }, g);
+}
+
 }  // namespace smith
+4 −0		.github/workflows/ci-tests.yml
+19 −14		src/gretl/data_store.cpp
+6 −3		src/gretl/data_store.hpp
+4 −2		src/gretl/state_base.cpp