The following is my HT prj for 2D mesh -
<?xml version='1.0' encoding='ISO-8859-1'?>
<OpenGeoSysProject>
<meshes>
<mesh>2Dmesh_initialfields.vtu</mesh>
<mesh>leftHT.vtu</mesh>
<mesh>2DboundaryHT.vtu</mesh>
</meshes>
<processes>
<process>
<name>th_decovalex</name>
<type>HT</type>
<coupling_scheme>staggered</coupling_scheme>
<integration_order>4</integration_order>
<process_variables>
<temperature>T</temperature>
<pressure>p</pressure>
</process_variables>
<specific_body_force>0 0 -9.81</specific_body_force>
<secondary_variables>
<secondary_variable internal_name="darcy_velocity" output_name="darcy_velocity" />
</secondary_variables>
</process>
</processes>
<media>
<medium id="0">
<phases>
<phase>
<type>AqueousLiquid</type>
<properties>
<property>
<name>density</name>
<type>Constant</type>
<value>1000</value>
</property>
<property>
<name>viscosity</name>
<type>Constant</type>
<value>1.0e-3</value>
</property>
<property>
<name>specific_heat_capacity</name>
<type>Constant</type>
<value>4000</value>
</property>
<property>
<name>thermal_conductivity</name>
<type>Constant</type>
<value>18921600</value>
</property>
</properties>
</phase>
<phase>
<type>Solid</type>
<properties>
<property>
<name>storage</name>
<type>Constant</type>
<value>1e-10</value>
</property>
<property>
<name>density</name>
<type>Constant</type>
<value>2700</value>
</property>
<property>
<name>thermal_conductivity</name>
<type>Constant</type>
<value>3.0 0 0 3.0</value>
</property>
<property>
<name>specific_heat_capacity</name>
<type>Constant</type>
<value>900</value>
</property>
</properties>
</phase>
</phases>
<properties>
<property>
<name>thermal_longitudinal_dispersivity</name>
<type>Constant</type>
<value>0.0</value>
</property>
<property>
<name>thermal_transversal_dispersivity</name>
<type>Constant</type>
<value>0.0</value>
</property>
<property>
<name>permeability</name>
<type>Constant</type>
<value>1e-13 0 0 0 1e-13 0 0 0 1e-13</value>
</property>
<property>
<name>porosity</name>
<type>Constant</type>
<value>0.30</value>
</property>
<property>
<name>thermal_conductivity</name>
<type>EffectiveThermalConductivityPorosityMixing</type>
</property>
</properties>
</medium>
<medium id="1">
<phases>
<phase>
<type>AqueousLiquid</type>
<properties>
<property>
<name>density</name>
<type>Constant</type>
<value>1000</value>
</property>
<property>
<name>viscosity</name>
<type>Constant</type>
<value>1.0e-3</value>
</property>
<property>
<name>specific_heat_capacity</name>
<type>Constant</type>
<value>4000</value>
</property>
<property>
<name>thermal_conductivity</name>
<type>Constant</type>
<value>18921600</value>
</property>
</properties>
</phase>
<phase>
<type>Solid</type>
<properties>
<property>
<name>storage</name>
<type>Constant</type>
<value>1e-10</value>
</property>
<property>
<name>density</name>
<type>Constant</type>
<value>2160</value>
</property>
<property>
<name>thermal_conductivity</name>
<type>Constant</type>
<value>5.5 0 0 5.5</value>
</property>
<property>
<name>specific_heat_capacity</name>
<type>Constant</type>
<value>900</value>
</property>
</properties>
</phase>
</phases>
<properties>
<property>
<name>thermal_longitudinal_dispersivity</name>
<type>Constant</type>
<value>0.0</value>
</property>
<property>
<name>thermal_transversal_dispersivity</name>
<type>Constant</type>
<value>0.0</value>
</property>
<property>
<name>permeability</name>
<type>Constant</type>
<value>5.5e-16 0 0 0 5.5e-16 0 0 0 5.5e-16 </value>
</property>
<property>
<name>porosity</name>
<type>Constant</type>
<value>0.12</value>
</property>
<property>
<name>thermal_conductivity</name>
<type>EffectiveThermalConductivityPorosityMixing</type>
</property>
</properties>
</medium>
</media>
<time_loop>
<global_process_coupling>
<max_iter>6</max_iter>
<convergence_criteria>
<convergence_criterion>
<type>DeltaX</type>
<norm_type>NORM2</norm_type>
<reltol>1.e-14</reltol>
</convergence_criterion>
<convergence_criterion>
<type>DeltaX</type>
<norm_type>NORM2</norm_type>
<reltol>1.e-14</reltol>
</convergence_criterion>
</convergence_criteria>
</global_process_coupling>
<processes>
<process ref="th_decovalex">
<nonlinear_solver>basic_picard_T</nonlinear_solver>
<convergence_criterion>
<type>DeltaX</type>
<norm_type>NORM2</norm_type>
<abstol>1.e-6</abstol>
</convergence_criterion>
<time_discretization>
<type>BackwardEuler</type>
</time_discretization>
<time_stepping>
<type>FixedTimeStepping</type>
<t_initial>0.0</t_initial>
<t_end>1e3</t_end>
<timesteps>
<pair>
<repeat>4</repeat>
<delta_t>0.001</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>0.006</delta_t>
</pair>
<pair>
<repeat>9</repeat>
<delta_t>0.01</delta_t>
</pair>
<pair>
<repeat>9</repeat>
<delta_t>0.1</delta_t>
</pair>
<pair>
<repeat>39</repeat>
<delta_t>1.</delta_t>
</pair>
<pair>
<repeat>2</repeat>
<delta_t>2.0</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>16.0</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>30.0</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>40.0</delta_t>
</pair>
<pair>
<repeat>10</repeat>
<delta_t>86.0</delta_t>
</pair>
<pair>
<repeat>90</repeat>
<delta_t>100.0</delta_t>
</pair>
<pair>
<repeat>100</repeat>
<delta_t>900</delta_t>
</pair>
<pair>
<repeat>90</repeat>
<delta_t>1.e4</delta_t>
</pair>
</timesteps>
</time_stepping>
</process>
<process ref="th_decovalex">
<nonlinear_solver>basic_picard_H</nonlinear_solver>
<convergence_criterion>
<type>DeltaX</type>
<norm_type>NORM2</norm_type>
<abstol>1.e-6</abstol>
</convergence_criterion>
<time_discretization>
<type>BackwardEuler</type>
</time_discretization>
<time_stepping>
<type>FixedTimeStepping</type>
<t_initial>0.0</t_initial>
<t_end>1.e3</t_end>
<timesteps>
<pair>
<repeat>4</repeat>
<delta_t>0.001</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>0.006</delta_t>
</pair>
<pair>
<repeat>9</repeat>
<delta_t>0.01</delta_t>
</pair>
<pair>
<repeat>9</repeat>
<delta_t>0.1</delta_t>
</pair>
<pair>
<repeat>39</repeat>
<delta_t>1.</delta_t>
</pair>
<pair>
<repeat>2</repeat>
<delta_t>2.0</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>16.0</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>30.0</delta_t>
</pair>
<pair>
<repeat>1</repeat>
<delta_t>40.0</delta_t>
</pair>
<pair>
<repeat>10</repeat>
<delta_t>86.0</delta_t>
</pair>
<pair>
<repeat>90</repeat>
<delta_t>100.0</delta_t>
</pair>
<pair>
<repeat>100</repeat>
<delta_t>900</delta_t>
</pair>
<pair>
<repeat>90</repeat>
<delta_t>1.e4</delta_t>
</pair>
</timesteps>
</time_stepping>
</process>
</processes>
<output>
<type>VTK</type>
<prefix>th_decovalex</prefix>
<suffix>ts{:timestep}_t_{:time}</suffix>
<timesteps>
<pair>
<repeat>1</repeat>
<each_steps>10</each_steps>
</pair>
</timesteps>
<variables>
<variable>T</variable>
<variable>p</variable>
<variable>darcy_velocity</variable>
</variables>
</output>
</time_loop>
<parameters>
<parameter>
<name>T0</name>
<type>Constant</type>
<value>283</value>
</parameter>
<parameter>
<name>heat_source</name>
<type>MeshNode</type>
<field_name>t_init</field_name>
</parameter>
<parameter>
<name>p_in</name>
<type>Constant</type>
<value>1.0e9</value>
</parameter>
<parameter>
<name>ic</name>
<type>MeshNode</type>
<field_name>p_init</field_name>
</parameter>
</parameters>
<process_variables>
<process_variable>
<name>T</name>
<components>1</components>
<order>1</order>
<initial_condition>heat_source</initial_condition>
<boundary_conditions>
<boundary_condition>
<mesh>2DboundaryHT</mesh>
<type>Dirichlet</type>
<parameter>T0</parameter>
</boundary_condition>
</boundary_conditions>
</process_variable>
<process_variable>
<name>p</name>
<components>1</components>
<order>1</order>
<!-- Hydrostatic Initial Condition -->
<initial_condition>ic</initial_condition>
<!-- Boundary Conditions -->
<boundary_conditions>
<boundary_condition>
<mesh>leftHT</mesh>
<type>Neumann</type>
<parameter>p_in</parameter>
</boundary_condition>
</boundary_conditions>
</process_variable>
</process_variables>
<nonlinear_solvers>
<nonlinear_solver>
<name>basic_picard_T</name>
<type>Picard</type>
<max_iter>10</max_iter>
<linear_solver>linear_solver_T</linear_solver>
</nonlinear_solver>
<nonlinear_solver>
<name>basic_picard_H</name>
<type>Picard</type>
<max_iter>10</max_iter>
<linear_solver>linear_solver_H</linear_solver>
</nonlinear_solver>
</nonlinear_solvers>
<linear_solvers>
<linear_solver>
<name>linear_solver_T</name>
<lis>-i cg -p jacobi -tol 1e-20 -maxiter 10000</lis>
<eigen>
<solver_type>BiCGSTAB</solver_type>
<precon_type>DIAGONAL</precon_type>
<max_iteration_step>10000</max_iteration_step>
<error_tolerance>1e-20</error_tolerance>
</eigen>
<petsc>
<prefix>T</prefix>
<parameters>-T_ksp_type bcgs -T_pc_type bjacobi -T_ksp_rtol 1e-16 -T_ksp_max_it 10000</parameters>
</petsc>
</linear_solver>
<linear_solver>
<name>linear_solver_H</name>
<lis>-i cg -p jacobi -tol 1e-20 -maxiter 10000</lis>
<eigen>
<solver_type>CG</solver_type>
<precon_type>DIAGONAL</precon_type>
<max_iteration_step>10000</max_iteration_step>
<error_tolerance>1e-20</error_tolerance>
</eigen>
<petsc>
<prefix>H</prefix>
<parameters>-H_ksp_type cg -H_pc_type bjacobi -H_ksp_rtol 1e-16 -H_ksp_max_it 10000</parameters>
</petsc>
</linear_solver>
</linear_solvers>
</OpenGeoSysProject>
My error persists when I convert it into 22 or 33
info: Global coupling iteration #0 started.
info: Solve process #0 (named as not given)
info: Iteration #1 started.
critical: C:/Users/gitlab/code/ogs/ogs/MaterialLib/MPL/Utils/FormEigenTensor.cpp:57 MaterialPropertyLib::FormEigenTensor<3>::operator ()()
warning: There are still 1 global matrices in use. This might be an indicator of a possible waste of memory.
warning: There are still 2 global vectors in use. This might be an indicator of a possible waste of memory.
error: Cannot convert a 2d tensor to 3x3 matrix
error: OGS terminated with error on 2025-09-13 22:45:32+0200.