feat(poly): added NonlinearPowerIntegrator and PolytropeOperator

A custom integrator is required to handle the theta^n term in the lane emden equation, that is written as NonlinearPowerIntegrator which is a mfem::NonlinearFormIntegrator and defines methods to assemble its element vector (function value) and element gradient matrix (jacobian). This is then, along with built in mfem vectors for M Q and D, incorporated into the PolytropeOperator which defines methods for Mult (calculate the residuals of the variational form) and GetGradient (find the jacobian of the system)

src/poly/utils/meson.build

@@ -1,24 +1,48 @@
+# ***********************************************************************
+#
+#   Copyright (C) 2025 -- The 4D-STAR Collaboration
+#   File Author: Emily Boudreaux
+#   Last Modified: March 19, 2025
+#
+#   4DSSE is free software; you can use it and/or modify
+#   it under the terms and restrictions the GNU General Library Public
+#   License version 3 (GPLv3) as published by the Free Software Foundation.
+#
+#   4DSSE is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#   See the GNU Library General Public License for more details.
+#
+#   You should have received a copy of the GNU Library General Public License
+#   along with this software; if not, write to the Free Software
+#   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+# *********************************************************************** #
 polyutils_sources = files(
-  'private/polyIO.cpp',
-  'private/polyMFEMUtils.cpp'
+  'private/integrators.cpp',
+  'private/operator.cpp'
 )
 
-polyutils_headers = files(
-  'public/polyIO.h',
-  'public/polyMFEMUtils.h'
-)
+dependencies = [
+  mfem_dep,
+  macros_dep,
+  probe_dep,
+  quill_dep,
+  config_dep,
+  types_dep,
+]
 
 libpolyutils = static_library('polyutils',
   polyutils_sources,
-  include_directories : include_directories('.'),
+  include_directories : include_directories('./public'),
   cpp_args: ['-fvisibility=default'],
-  dependencies: [mfem_dep],
+  dependencies: dependencies,
   install: true
 )
 
-libpolyutils_dep = declare_dependency(
-  include_directories : include_directories('.'),
+polyutils_dep = declare_dependency(
+  include_directories : include_directories('./public'),
   link_with : libpolyutils,
   sources : polyutils_sources,
-  dependencies : [mfem_dep]
+  dependencies : dependencies
 )