diff --git a/.github/workflows/continuous.yml b/.github/workflows/continuous.yml
index d94039d0..2b34a70f 100644
--- a/.github/workflows/continuous.yml
+++ b/.github/workflows/continuous.yml
@@ -15,13 +15,14 @@ jobs:
   ####################
 
   Unix:
-    name: ${{ matrix.name }} (${{ matrix.config }})
+    name: ${{ matrix.name }} (${{ matrix.config }}, large_index=${{ matrix.large_index }})
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest]
         config: [Debug, Release]
+        large_index: [ON, OFF]
         include:
           - os: macos-latest
             name: macOS
@@ -57,8 +58,8 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.CACHE_PATH }}
-          key: ${{ runner.os }}-${{ matrix.config }}-cache-${{ github.sha }}
-          restore-keys: ${{ runner.os }}-${{ matrix.config }}-cache
+          key: ${{ runner.os }}-${{ matrix.config }}-${{ matrix.large_index }}-cache-${{ github.sha }}
+          restore-keys: ${{ runner.os }}-${{ matrix.config }}-${{ matrix.large_index }}-cache
 
       - name: Prepare ccache
         run: |
@@ -71,6 +72,7 @@ jobs:
           cd build
           cmake .. \
             -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
+            -DPOLYSOLVE_LARGE_INDEX=${{ matrix.large_index }} \
             -DCMAKE_BUILD_TYPE=${{ matrix.config }} \
 
       - name: Build
@@ -84,6 +86,7 @@ jobs:
   ####################
 
   Windows:
+    name: Windows (${{ matrix.config }}, large_index=${{ matrix.large_index }})
     runs-on: windows-latest
     env:
       SCCACHE_IDLE_TIMEOUT: "12000"
@@ -91,6 +94,7 @@ jobs:
       fail-fast: false
       matrix:
         config: [Debug, Release]
+        large_index: [ON, OFF]
     steps:
       - name: Checkout repository
         uses: actions/checkout@v6
@@ -106,8 +110,8 @@ jobs:
         uses: actions/cache@v5
         with:
           path: ${{ env.appdata }}\Mozilla\sccache
-          key: ${{ runner.os }}-${{ matrix.config }}-cache-${{ github.sha }}
-          restore-keys: ${{ runner.os }}-${{ matrix.config }}-cache
+          key: ${{ runner.os }}-${{ matrix.config }}-${{ matrix.large_index }}-cache-${{ github.sha }}
+          restore-keys: ${{ runner.os }}-${{ matrix.config }}-${{ matrix.large_index }}-cache
 
       - name: Prepare sccache
         run: |
@@ -130,6 +134,7 @@ jobs:
             -DCMAKE_C_COMPILER=cl.exe ^
             -DCMAKE_CXX_COMPILER=cl.exe ^
             -DCMAKE_CXX_COMPILER_LAUNCHER=sccache ^
+            -DPOLYSOLVE_LARGE_INDEX=${{ matrix.large_index }} ^
             -DCMAKE_BUILD_TYPE=${{ matrix.config }} ^
             -B build ^
             -S .
diff --git a/src/polysolve/linear/CMakeLists.txt b/src/polysolve/linear/CMakeLists.txt
index 0430402b..03916f9d 100644
--- a/src/polysolve/linear/CMakeLists.txt
+++ b/src/polysolve/linear/CMakeLists.txt
@@ -28,7 +28,7 @@ if(POLYSOLVE_WITH_CUDA)
     )
 endif()
 
-if(POLYSOLVE_WITH_MPI)
+if(POLYSOLVE_WITH_MPI AND NOT POLYSOLVE_LARGE_INDEX)
     list(APPEND SOURCES
         CPUHybridSolver.cpp
         CPUHybridSolver.hpp
diff --git a/src/polysolve/linear/SaddlePointSolver.cpp b/src/polysolve/linear/SaddlePointSolver.cpp
index 6d974b25..b900108d 100644
--- a/src/polysolve/linear/SaddlePointSolver.cpp
+++ b/src/polysolve/linear/SaddlePointSolver.cpp
@@ -57,8 +57,13 @@ namespace polysolve::linear
         conv_tol_ = 1e-8;
         max_iter_ = 50;
 
+#ifdef POLYSOLVE_LARGE_INDEX
+        asymmetric_solver_name_ = "Eigen::SparseLU";
+        symmetric_solver_name_ = "Eigen::SimplicialLDLT";
+#else
         asymmetric_solver_name_ = "Eigen::GMRES";
         symmetric_solver_name_ = "Eigen::GMRES";
+#endif
 
         asymmetric_solver_params_ = {"tolerance", 1e-4};
         symmetric_solver_params_ = {"tolerance", 1e-4};
diff --git a/src/polysolve/linear/Solver.cpp b/src/polysolve/linear/Solver.cpp
index 9bb5070c..f112b702 100644
--- a/src/polysolve/linear/Solver.cpp
+++ b/src/polysolve/linear/Solver.cpp
@@ -548,8 +548,10 @@ namespace polysolve::linear
             "Eigen::CholmodSimplicialLDLT",
 #endif
 #ifdef POLYSOLVE_WITH_UMFPACK
+#ifndef POLYSOLVE_LARGE_INDEX
             "Eigen::UmfPackLU",
 #endif
+#endif
 #ifdef POLYSOLVE_WITH_SUPERLU
             "Eigen::SuperLU",
 #endif
@@ -594,10 +596,12 @@ namespace polysolve::linear
             "Eigen::DGMRES",
 #endif
 #endif
+#ifndef POLYSOLVE_LARGE_INDEX
             "Eigen::ConjugateGradient",
             "Eigen::BiCGSTAB",
             "Eigen::GMRES",
             "Eigen::MINRES",
+#endif
             "Eigen::PartialPivLU",
             "Eigen::FullPivLU",
             "Eigen::HouseholderQR",