[DRAFT] Move solve to GPU

CMakeLists.txt

@@ -121,6 +121,12 @@ if(NOT DEFINED QOCO_ALGEBRA_BACKEND)
     set(QOCO_ALGEBRA_BACKEND "builtin" CACHE STRING "The Algebra to use")
 endif()
 message(STATUS "Using ${QOCO_ALGEBRA_BACKEND} algebra")
+# Propagate backend choice to all targets
+if(${QOCO_ALGEBRA_BACKEND} STREQUAL "cuda")
+    add_compile_definitions(QOCO_ALGEBRA_BACKEND_CUDA)
+else()
+    add_compile_definitions(QOCO_ALGEBRA_BACKEND_BUILTIN)
+endif()
 
 # Enable CUDA if using CUDA backend
 if(${QOCO_ALGEBRA_BACKEND} STREQUAL "cuda")

algebra/builtin/builtin_linalg.c

@@ -99,10 +99,15 @@ QOCOInt get_length_vectorf(const QOCOVectorf* x) { return x->len; }
 
 // No-op for builtin backend
 void sync_vector_to_host(QOCOVectorf* v) {}
+// No-op for builtin backend
+void sync_vector_to_device(const QOCOVectorf* v) {}
 
 // No-op for builtin backend
 void set_solve_phase(int active) {}
 
+// No-op for builtin backend
+void set_scaling_statistics_mode(int active) {}
+
 QOCOCscMatrix* get_csc_matrix(const QOCOMatrix* M) { return M->csc; }
 
 void col_inf_norm_USymm_matrix(const QOCOMatrix* M, QOCOFloat* norm)

algebra/builtin/qdldl_backend.c

@@ -205,7 +205,7 @@ static void qdldl_solve(LinSysData* linsys_data, QOCOWorkspace* work,
       x[linsys_data->p[k]] = linsys_data->xyzbuff1[k];
     }
 
-    kkt_multiply(x, linsys_data->xyzbuff2, work->data, work->Wfull, work->xbuff,
+    kkt_multiply(x, linsys_data->xyzbuff2, work->data, work->Wfull, get_data_vectorf(work->xbuff),
                  work->ubuff1, work->ubuff2);
     for (QOCOInt k = 0; k < linsys_data->K->n; ++k) {
       x[k] = linsys_data->xyzbuff2[linsys_data->p[k]];