--- src/compute_groupcond_logl.cpp	2023-10-25 16:24:00.000000000 +0800
+++ src/compute_groupcond_logl.cpp	2023-11-05 22:31:15.000000000 +0800
@@ -2,6 +2,11 @@
 // [[Rcpp::depends("RcppArmadillo")]]
 #include "creg_header_funs.h"
 #include <RcppArmadillo.h>
+
+#if defined(_OPENMP)
+#include <omp.h>
+#endif
+
 using namespace Rcpp;
 
 // [[Rcpp::plugins(openmp)]]