diff --git a/source/module_hamilt_general/module_xc/xc_functional_gradcorr.cpp b/source/module_hamilt_general/module_xc/xc_functional_gradcorr.cpp
index 75acbbcfe44..4d373ef950b 100644
--- a/source/module_hamilt_general/module_xc/xc_functional_gradcorr.cpp
+++ b/source/module_hamilt_general/module_xc/xc_functional_gradcorr.cpp
@@ -233,9 +233,10 @@ void XC_Functional::gradcorr(double &etxc, double &vtxc, ModuleBase::matrix &v,
 			if(arho > epsr)
 			{
 				grho2a = gdr1[ir].norm2();
-
+				
+				//normally values in rhotmp can either be >= 0 or < 0.
 				if( rhotmp1[ir] >= 0.0 ) segno = 1.0;
-				if( rhotmp1[ir] < 0.0 ) segno = -1.0;
+				else segno = -1.0;
 				if (use_libxc && is_stress)
 				{
 #ifdef USE_LIBXC
diff --git a/source/module_hamilt_pw/hamilt_pwdft/wavefunc.cpp b/source/module_hamilt_pw/hamilt_pwdft/wavefunc.cpp
index cd66bd5fc96..ac168199670 100644
--- a/source/module_hamilt_pw/hamilt_pwdft/wavefunc.cpp
+++ b/source/module_hamilt_pw/hamilt_pwdft/wavefunc.cpp
@@ -779,23 +779,24 @@ int wavefunc::get_R(int ix, int iy, int iz)   // pengfei 2016-11-23
 }
 
 
-int wavefunc::iw2it( int iw)    // pengfei 2016-11-23
+int wavefunc::iw2it(int iw)    // pengfei 2016-11-23
 {
     int ic, type;
-    ic =0;
-    for(int it =0; it<GlobalC::ucell.ntype; it++)
+    ic = 0;
+    type = 0;
+    for(int it = 0; it<GlobalC::ucell.ntype; it++)
 	{
         for(int ia = 0; ia<GlobalC::ucell.atoms[it].na; ia++)
         {
-            for(int L=0; L<GlobalC::ucell.atoms[it].nwl+1; L++)
+            for(int L = 0; L<GlobalC::ucell.atoms[it].nwl+1; L++)
 			{
-                for(int N=0; N<GlobalC::ucell.atoms[it].l_nchi[L]; N++)
+                for(int N = 0; N<GlobalC::ucell.atoms[it].l_nchi[L]; N++)
                 {
                     for(int i=0; i<(2*L+1); i++)
                     {
                         if(ic == iw)
                         {
-                           type = it;
+                            type = it;
                         }
                         ic++;
 					}
@@ -809,7 +810,8 @@ int wavefunc::iw2it( int iw)    // pengfei 2016-11-23
 int wavefunc::iw2ia( int iw)    // pengfei 2016-11-23
 {
 	int ic, na;
-	ic =0;
+	ic = 0;
+    na = 0;
 	for(int it =0; it<GlobalC::ucell.ntype; it++)
 	{
 		for(int ia = 0; ia<GlobalC::ucell.atoms[it].na; ia++)
diff --git a/source/module_io/unk_overlap_lcao.cpp b/source/module_io/unk_overlap_lcao.cpp
index 6c26ee05be8..6c1af94d33a 100644
--- a/source/module_io/unk_overlap_lcao.cpp
+++ b/source/module_io/unk_overlap_lcao.cpp
@@ -239,10 +239,13 @@ void unkOverlap_lcao::init(const Grid_Technique& gt, std::complex<double>*** wfc
 	return;
 }
 
+//REMARK: the code next seemed to duplicate with those in 
+//module_hamilt_pw/hamilt/pwdft/wavefunc.cpp.
 int unkOverlap_lcao::iw2it(int iw)
 {
     int ic, type;
     ic = 0;
+	type = 0;
     for(int it = 0; it < GlobalC::ucell.ntype; it++)
 	{
         for(int ia = 0; ia < GlobalC::ucell.atoms[it].na; ia++)
@@ -255,7 +258,7 @@ int unkOverlap_lcao::iw2it(int iw)
                     {
                         if(ic == iw)
                         {
-                           type = it;
+                            type = it;
                         }
                         ic++;
 					}
@@ -270,9 +273,10 @@ int unkOverlap_lcao::iw2ia(int iw)
 {
     int ic, na;
     ic = 0;
+	na = 0;
     for(int it = 0; it < GlobalC::ucell.ntype; it++)
 	{
-        for(int ia = 0; ia<  GlobalC::ucell.atoms[it].na; ia++)
+        for(int ia = 0; ia < GlobalC::ucell.atoms[it].na; ia++)
         {
             for(int L = 0; L < GlobalC::ucell.atoms[it].nwl+1; L++)
 			{
@@ -282,7 +286,7 @@ int unkOverlap_lcao::iw2ia(int iw)
                     {
                         if(ic == iw)
                         {
-                           na = ia;
+                            na = ia;
                         }
                         ic++;
                     } 
@@ -297,9 +301,10 @@ int unkOverlap_lcao::iw2iL(int iw)
 {
 	int ic, iL;
     ic = 0;
+	iL = 0;
     for(int it = 0; it < GlobalC::ucell.ntype; it++)
 	{
-        for(int ia = 0; ia<  GlobalC::ucell.atoms[it].na; ia++)
+        for(int ia = 0; ia < GlobalC::ucell.atoms[it].na; ia++)
         {
             for(int L = 0; L < GlobalC::ucell.atoms[it].nwl+1; L++)
 			{
@@ -309,7 +314,7 @@ int unkOverlap_lcao::iw2iL(int iw)
                     {
                         if(ic == iw)
                         {
-                           iL = L;
+                            iL = L;
                         }
                         ic++;
                     } 
@@ -324,9 +329,10 @@ int unkOverlap_lcao::iw2iN(int iw)
 {
 	int ic, iN;
     ic = 0;
+	iN = 0;
     for(int it = 0; it < GlobalC::ucell.ntype; it++)
 	{
-        for(int ia = 0; ia<  GlobalC::ucell.atoms[it].na; ia++)
+        for(int ia = 0; ia < GlobalC::ucell.atoms[it].na; ia++)
         {
             for(int L = 0; L < GlobalC::ucell.atoms[it].nwl+1; L++)
 			{
@@ -336,7 +342,7 @@ int unkOverlap_lcao::iw2iN(int iw)
                     {
                         if(ic == iw)
                         {
-                           iN = N;
+                            iN = N;
                         }
                         ic++;
                     } 
@@ -351,9 +357,10 @@ int unkOverlap_lcao::iw2im(int iw)
 {
 	int ic, im;
     ic = 0;
+	im = 0;
     for(int it = 0; it < GlobalC::ucell.ntype; it++)
 	{
-        for(int ia = 0; ia<  GlobalC::ucell.atoms[it].na; ia++)
+        for(int ia = 0; ia < GlobalC::ucell.atoms[it].na; ia++)
         {
             for(int L = 0; L < GlobalC::ucell.atoms[it].nwl+1; L++)
 			{
@@ -363,7 +370,7 @@ int unkOverlap_lcao::iw2im(int iw)
                     {
                         if(ic == iw)
                         {
-                           im = i;
+                            im = i;
                         }
                         ic++;
                     } 
diff --git a/source/module_relax/relax_new/relax.cpp b/source/module_relax/relax_new/relax.cpp
index bf4b5d0279d..06b75acb44f 100644
--- a/source/module_relax/relax_new/relax.cpp
+++ b/source/module_relax/relax_new/relax.cpp
@@ -411,7 +411,8 @@ void Relax::new_direction()
     //prepare for line search
     bool restart = true;
     double x=0, y=etot;
-    double xnew, yd;
+    //TODO: add a certain threshold for the progress.
+    double xnew, yd = 1e-8;
 
     this->ls.line_search(restart, x, y, f, xnew, yd);