work around stupid g++11 implementation to allocate am_2[0]

src/cluster/cluster.cpp

@@ -501,9 +501,9 @@ void cluster(string config_file, string data_file, string output_path) {
 	double vk_2 = vk;
 	np_int ndit_2 = ndit;
 	dcomplex **am_2 = new dcomplex*[ndit];
-	dcomplex am_2[0] = new dcomplex[ndit * ndit]();
-	for (int ai = 1; ai < ndit; ai++) {
-	  am_2[ai] = (am_2[0] + ai * ndit);
+	dcomplex *am_vector_2 = new dcomplex[ndit * ndit]();
+	for (int ai = 0; ai < ndit; ai++) {
+	  am_2[ai] = (am_vector_2 + ai * ndit);
 	}
 	int isq_2 = isq;
 	int ibf_2 = ibf;
@@ -586,7 +586,7 @@ void cluster(string config_file, string data_file, string output_path) {
 	delete[] unsmp_2;
 	delete[] upmp_2;
 	delete[] upsmp_2;
-	delete[] am_2[0];
+	delete[] am_vector_2;
 	delete[] am_2;
 	
       } // jxi488 loop