Add OpenMP parallelization

Author: foxtran

fortran/solver/CMakeLists.txt

@@ -4,15 +4,23 @@ project(solver
   VERSION 0.0.0
   LANGUAGES Fortran)
 
+option(ENABLE_OPENMP "Enable OpenMP parallelization" OFF)
+
 include(CheckIPOSupported)
 
 set(PN ${PROJECT_NAME})
 
 check_ipo_supported(RESULT IPO_AVAILABLE)
+if(ENABLE_OPENMP)
+  find_package(OpenMP 3.0 REQUIRED)
+endif()
 
 add_subdirectory(src)
 
 add_executable(${PN} ${SOURCES})
+if(ENABLE_OPENMP)
+  target_link_libraries(${PN} PUBLIC OpenMP::OpenMP_Fortran)
+endif()
 if(IPO_AVAILABLE)
   set_target_properties(${PN} PROPERTIES INTERPROCEDURAL_OPTIMIZATION TRUE)
 endif()

fortran/solver/src/solver.f90

@@ -69,15 +69,19 @@ subroutine solve(solver)
             end do
             do iter = 1, 3 * 9 * size(solver%library%rooms)
                 max_length = 0
+                !$omp parallel do default(none) &
+                !$omp reduction(max:max_length) &
+                !$omp private(guess_id) &
+                !$omp shared(solver, guess, corr_id)
                 do guess_id = 1, N_guess
                     call guess(guess_id)%eval()
                     call guess(guess_id)%next()
                     max_length = max(max_length, guess(guess_id)%max_length)
                     if (max_length == size(solver%library%plans(1)%steps)) then
                         corr_id = guess_id
-                        exit infinity
                     end if
                 end do
+                if (corr_id /= -1) exit infinity
                 print '("iter: ",I4," ML:",I4)', iter, max_length
             end do
         end do infinity