diff --git a/CMakeLists.txt b/CMakeLists.txt
index b91d361..1f1f36d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -61,7 +61,7 @@ set (REPLACE_SRC
   src/fft.cpp
   src/fftsg.cpp
   src/fftsg2d.cpp
-  src/coordi.cpp
+  src/point.cpp
   src/plot.cpp
   src/logger.cpp
   )
diff --git a/src/coordi.cpp b/src/coordi.cpp
deleted file mode 100644
index e887e06..0000000
--- a/src/coordi.cpp
+++ /dev/null
@@ -1,17 +0,0 @@
-#include "coordi.h"
-
-namespace replace {
-
-FloatCoordi::FloatCoordi() : x(0), y(0) {}
-FloatCoordi::FloatCoordi(float inputX, float inputY) {
-  x = inputX; 
-  y = inputY;
-}
-
-IntCoordi::IntCoordi() : x(0), y(0) {}
-IntCoordi::IntCoordi(int inputX, int inputY) {
-  x = inputX;
-  y = inputY;
-}
-}
-
diff --git a/src/nesterovBase.cpp b/src/nesterovBase.cpp
index cf3c2a6..e04ae41 100644
--- a/src/nesterovBase.cpp
+++ b/src/nesterovBase.cpp
@@ -1170,7 +1170,7 @@ NesterovBase::placerToNesterov(Pin* pin) {
 // gcell update
 void
 NesterovBase::updateGCellLocation(
-    std::vector<FloatCoordi>& coordis) {
+    std::vector<FloatPoint>& coordis) {
   for(auto& coordi : coordis) {
     int idx = &coordi - &coordis[0];
     gCells_[idx]->setLocation( coordi.x, coordi.y );
@@ -1180,7 +1180,7 @@ NesterovBase::updateGCellLocation(
 // gcell update
 void
 NesterovBase::updateGCellCenterLocation(
-    std::vector<FloatCoordi>& coordis) {
+    std::vector<FloatPoint>& coordis) {
   for(auto& coordi : coordis) {
     int idx = &coordi - &coordis[0];
     gCells_[idx]->setCenterLocation( coordi.x, coordi.y );
@@ -1189,7 +1189,7 @@ NesterovBase::updateGCellCenterLocation(
 
 void
 NesterovBase::updateGCellDensityCenterLocation(
-    std::vector<FloatCoordi>& coordis) {
+    std::vector<FloatPoint>& coordis) {
   for(auto& coordi : coordis) {
     int idx = &coordi - &coordis[0];
     gCells_[idx]->setDensityCenterLocation( 
@@ -1347,9 +1347,9 @@ NesterovBase::updateWireLengthForceWA(
 }
 
 // get x,y WA Gradient values with given GCell
-FloatCoordi
+FloatPoint
 NesterovBase::getWireLengthGradientWA(GCell* gCell, float wlCoeffX, float wlCoeffY) {
-  FloatCoordi gradientPair;
+  FloatPoint gradientPair;
 
   for(auto& gPin : gCell->gPins()) {
     auto tmpPair = getWireLengthGradientPinWA(gPin, wlCoeffX, wlCoeffY);
@@ -1367,7 +1367,7 @@ NesterovBase::getWireLengthGradientWA(GCell* gCell, float wlCoeffX, float wlCoef
 //
 // You can't understand the following function
 // unless you read the (4.13) formula
-FloatCoordi
+FloatPoint
 NesterovBase::getWireLengthGradientPinWA(GPin* gPin, float wlCoeffX, float wlCoeffY) {
 
   float gradientMinX = 0, gradientMinY = 0;
@@ -1422,34 +1422,34 @@ NesterovBase::getWireLengthGradientPinWA(GPin* gPin, float wlCoeffX, float wlCoe
         / ( waExpMaxSumY * waExpMaxSumY );
   }
 
-  return FloatCoordi(gradientMinX - gradientMaxX, 
+  return FloatPoint(gradientMinX - gradientMaxX, 
       gradientMinY - gradientMaxY);
 }
 
-FloatCoordi
+FloatPoint
 NesterovBase::getWireLengthPreconditioner(GCell* gCell) {
-  return FloatCoordi( gCell->gPins().size(), 
+  return FloatPoint( gCell->gPins().size(), 
      gCell->gPins().size() );
 }
 
-FloatCoordi
+FloatPoint
 NesterovBase::getDensityPreconditioner(GCell* gCell) {
   float areaVal = static_cast<float>(gCell->dx()) 
     * static_cast<float>(gCell->dy());
 
-  return FloatCoordi(areaVal, areaVal);
+  return FloatPoint(areaVal, areaVal);
 }
 
 // get GCells' electroForcePair
 // i.e. get DensityGradient with given GCell
-FloatCoordi 
+FloatPoint 
 NesterovBase::getDensityGradient(GCell* gCell) {
   std::pair<int, int> pairX 
     = bg_.getDensityMinMaxIdxX(gCell);
   std::pair<int, int> pairY 
     = bg_.getDensityMinMaxIdxY(gCell);
   
-  FloatCoordi electroForce;
+  FloatPoint electroForce;
 
   for(int i = pairX.first; i < pairX.second; i++) {
     for(int j = pairY.first; j < pairY.second; j++) {
diff --git a/src/nesterovBase.h b/src/nesterovBase.h
index aa1e613..6861087 100644
--- a/src/nesterovBase.h
+++ b/src/nesterovBase.h
@@ -5,7 +5,7 @@
 #include <memory>
 #include <unordered_map>
 
-#include "coordi.h"
+#include "point.h"
 
 namespace replace {
 
@@ -730,14 +730,14 @@ public:
 
   // update gCells with lx, ly
   void updateGCellLocation(
-      std::vector<FloatCoordi>& coordis);
+      std::vector<FloatPoint>& points);
 
   // update gCells with cx, cy
   void updateGCellCenterLocation(
-      std::vector<FloatCoordi>& coordis);
+      std::vector<FloatPoint>& points);
 
   void updateGCellDensityCenterLocation(
-      std::vector<FloatCoordi>& coordis);
+      std::vector<FloatPoint>& points);
 
   int binCntX() const;
   int binCntY() const;
@@ -766,22 +766,22 @@ public:
       float wlCoeffX,
       float wlCoeffY);
 
-  FloatCoordi
+  FloatPoint
     getWireLengthGradientPinWA(GPin* gPin,
         float wlCoeffX, float wlCoeffY);
 
-  FloatCoordi
+  FloatPoint
     getWireLengthGradientWA(GCell* gCell,
         float wlCoeffX, float wlCoeffY);
 
   // for preconditioner
-  FloatCoordi
+  FloatPoint
     getWireLengthPreconditioner(GCell* gCell);
 
-  FloatCoordi
+  FloatPoint
     getDensityPreconditioner(GCell* gCell);
 
-  FloatCoordi
+  FloatPoint
     getDensityGradient(GCell* gCell);
 
   int64_t getHpwl();
diff --git a/src/nesterovPlace.cpp b/src/nesterovPlace.cpp
index 25e4d81..6a6d4f1 100644
--- a/src/nesterovPlace.cpp
+++ b/src/nesterovPlace.cpp
@@ -11,10 +11,10 @@ using namespace std;
 namespace replace {
 
 static float
-getDistance(vector<FloatCoordi>& a, vector<FloatCoordi>& b);
+getDistance(vector<FloatPoint>& a, vector<FloatPoint>& b);
 
 static float
-getSecondNorm(vector<FloatCoordi>& a);
+getSecondNorm(vector<FloatPoint>& a);
 
 NesterovPlaceVars::NesterovPlaceVars()
   : maxNesterovIter(2000), 
@@ -65,23 +65,23 @@ void NesterovPlace::init() {
   log_->procBegin("NesterovInit", 3);
 
   const int gCellSize = nb_->gCells().size();
-  curSLPCoordi_.resize(gCellSize, FloatCoordi());
-  curSLPWireLengthGrads_.resize(gCellSize, FloatCoordi());
-  curSLPDensityGrads_.resize(gCellSize, FloatCoordi());
-  curSLPSumGrads_.resize(gCellSize, FloatCoordi());
+  curSLPCoordi_.resize(gCellSize, FloatPoint());
+  curSLPWireLengthGrads_.resize(gCellSize, FloatPoint());
+  curSLPDensityGrads_.resize(gCellSize, FloatPoint());
+  curSLPSumGrads_.resize(gCellSize, FloatPoint());
 
-  nextSLPCoordi_.resize(gCellSize, FloatCoordi());
-  nextSLPWireLengthGrads_.resize(gCellSize, FloatCoordi());
-  nextSLPDensityGrads_.resize(gCellSize, FloatCoordi());
-  nextSLPSumGrads_.resize(gCellSize, FloatCoordi());
+  nextSLPCoordi_.resize(gCellSize, FloatPoint());
+  nextSLPWireLengthGrads_.resize(gCellSize, FloatPoint());
+  nextSLPDensityGrads_.resize(gCellSize, FloatPoint());
+  nextSLPSumGrads_.resize(gCellSize, FloatPoint());
   
-  prevSLPCoordi_.resize(gCellSize, FloatCoordi());
-  prevSLPWireLengthGrads_.resize(gCellSize, FloatCoordi());
-  prevSLPDensityGrads_.resize(gCellSize, FloatCoordi());
-  prevSLPSumGrads_.resize(gCellSize, FloatCoordi());
+  prevSLPCoordi_.resize(gCellSize, FloatPoint());
+  prevSLPWireLengthGrads_.resize(gCellSize, FloatPoint());
+  prevSLPDensityGrads_.resize(gCellSize, FloatPoint());
+  prevSLPSumGrads_.resize(gCellSize, FloatPoint());
 
-  curCoordi_.resize(gCellSize, FloatCoordi());
-  nextCoordi_.resize(gCellSize, FloatCoordi());
+  curCoordi_.resize(gCellSize, FloatPoint());
+  nextCoordi_.resize(gCellSize, FloatPoint());
 
   for(auto& gCell : nb_->gCells()) {
     nb_->updateDensityCoordiLayoutInside( gCell );
@@ -89,7 +89,7 @@ void NesterovPlace::init() {
     curSLPCoordi_[idx] 
       = prevSLPCoordi_[idx] 
       = curCoordi_[idx] 
-      = FloatCoordi(gCell->dCx(), gCell->dCy()); 
+      = FloatPoint(gCell->dCx(), gCell->dCy()); 
   }
 
   // bin update
@@ -174,23 +174,23 @@ void NesterovPlace::init() {
 
 // clear reset
 void NesterovPlace::reset() {
-  vector<FloatCoordi> ().swap(curSLPCoordi_);
-  vector<FloatCoordi> ().swap(curSLPWireLengthGrads_);
-  vector<FloatCoordi> ().swap(curSLPDensityGrads_);
-  vector<FloatCoordi> ().swap(curSLPSumGrads_);
+  vector<FloatPoint> ().swap(curSLPCoordi_);
+  vector<FloatPoint> ().swap(curSLPWireLengthGrads_);
+  vector<FloatPoint> ().swap(curSLPDensityGrads_);
+  vector<FloatPoint> ().swap(curSLPSumGrads_);
 
-  vector<FloatCoordi> ().swap(nextSLPCoordi_);
-  vector<FloatCoordi> ().swap(nextSLPWireLengthGrads_);
-  vector<FloatCoordi> ().swap(nextSLPDensityGrads_);
-  vector<FloatCoordi> ().swap(nextSLPSumGrads_);
+  vector<FloatPoint> ().swap(nextSLPCoordi_);
+  vector<FloatPoint> ().swap(nextSLPWireLengthGrads_);
+  vector<FloatPoint> ().swap(nextSLPDensityGrads_);
+  vector<FloatPoint> ().swap(nextSLPSumGrads_);
 
-  vector<FloatCoordi> ().swap(prevSLPCoordi_);
-  vector<FloatCoordi> ().swap(prevSLPWireLengthGrads_);
-  vector<FloatCoordi> ().swap(prevSLPDensityGrads_);
-  vector<FloatCoordi> ().swap(prevSLPSumGrads_);
+  vector<FloatPoint> ().swap(prevSLPCoordi_);
+  vector<FloatPoint> ().swap(prevSLPWireLengthGrads_);
+  vector<FloatPoint> ().swap(prevSLPDensityGrads_);
+  vector<FloatPoint> ().swap(prevSLPSumGrads_);
 
-  vector<FloatCoordi> ().swap(curCoordi_);
-  vector<FloatCoordi> ().swap(nextCoordi_);
+  vector<FloatPoint> ().swap(curCoordi_);
+  vector<FloatPoint> ().swap(nextCoordi_);
 }
 
 // to execute following function,
@@ -202,9 +202,9 @@ void NesterovPlace::reset() {
 //
 void
 NesterovPlace::updateGradients(
-    std::vector<FloatCoordi>& sumGrads,
-    std::vector<FloatCoordi>& wireLengthGrads,
-    std::vector<FloatCoordi>& densityGrads) {
+    std::vector<FloatPoint>& sumGrads,
+    std::vector<FloatPoint>& wireLengthGrads,
+    std::vector<FloatPoint>& densityGrads) {
 
   wireLengthGradSum_ = 0;
   densityGradSum_ = 0;
@@ -234,12 +234,12 @@ NesterovPlace::updateGradients(
     sumGrads[i].x = wireLengthGrads[i].x + densityPenalty_ * densityGrads[i].x;
     sumGrads[i].y = wireLengthGrads[i].y + densityPenalty_ * densityGrads[i].y;
 
-    FloatCoordi wireLengthPreCondi 
+    FloatPoint wireLengthPreCondi 
       = nb_->getWireLengthPreconditioner(gCell);
-    FloatCoordi densityPrecondi
+    FloatPoint densityPrecondi
       = nb_->getDensityPreconditioner(gCell);
 
-    FloatCoordi sumPrecondi(
+    FloatPoint sumPrecondi(
         wireLengthPreCondi.x + densityPenalty_ * densityPrecondi.x,
         wireLengthPreCondi.y + densityPenalty_ * densityPrecondi.y);
 
@@ -323,25 +323,25 @@ NesterovPlace::doNesterovPlace() {
       
       // fill in nextCoordinates with given stepLength_
       for(size_t k=0; k<nb_->gCells().size(); k++) {
-        FloatCoordi nextCoordi(
+        FloatPoint nextCoordi(
           curSLPCoordi_[k].x + stepLength_ * curSLPSumGrads_[k].x,
           curSLPCoordi_[k].y + stepLength_ * curSLPSumGrads_[k].y );
 
-        FloatCoordi nextSLPCoordi(
+        FloatPoint nextSLPCoordi(
           nextCoordi.x + coeff * (nextCoordi.x - curCoordi_[k].x),
           nextCoordi.y + coeff * (nextCoordi.y - curCoordi_[k].y));
 
         GCell* curGCell = nb_->gCells()[k];
 
         nextCoordi_[k] 
-          = FloatCoordi( 
+          = FloatPoint( 
               nb_->getDensityCoordiLayoutInsideX( 
                 curGCell, nextCoordi.x),
               nb_->getDensityCoordiLayoutInsideY(
                 curGCell, nextCoordi.y));
         
         nextSLPCoordi_[k]
-          = FloatCoordi(
+          = FloatPoint(
               nb_->getDensityCoordiLayoutInsideX(
                 curGCell, nextSLPCoordi.x),
               nb_->getDensityCoordiLayoutInsideY(
@@ -486,7 +486,7 @@ NesterovPlace::updateInitialPrevSLPCoordi() {
       = curSLPCoordi_[i].y + npVars_.initialPrevCoordiUpdateCoef
       * curSLPSumGrads_[i].y;
     
-    FloatCoordi newCoordi( 
+    FloatPoint newCoordi( 
       nb_->getDensityCoordiLayoutInsideX( curGCell, prevCoordiX),
       nb_->getDensityCoordiLayoutInsideY( curGCell, prevCoordiY) );
 
@@ -536,10 +536,10 @@ NesterovPlace::updateNextIter() {
 
 float
 NesterovPlace::getStepLength(
-    std::vector<FloatCoordi>& prevSLPCoordi_,
-    std::vector<FloatCoordi>& prevSLPSumGrads_,
-    std::vector<FloatCoordi>& curSLPCoordi_,
-    std::vector<FloatCoordi>& curSLPSumGrads_ ) {
+    std::vector<FloatPoint>& prevSLPCoordi_,
+    std::vector<FloatPoint>& prevSLPSumGrads_,
+    std::vector<FloatPoint>& curSLPCoordi_,
+    std::vector<FloatPoint>& curSLPSumGrads_ ) {
 
   float coordiDistance 
     = getDistance(prevSLPCoordi_, curSLPCoordi_);
@@ -578,7 +578,7 @@ NesterovPlace::updateDb() {
 
 
 static float
-getDistance(vector<FloatCoordi>& a, vector<FloatCoordi>& b) {
+getDistance(vector<FloatPoint>& a, vector<FloatPoint>& b) {
   float sumDistance = 0.0f;
   for(size_t i=0; i<a.size(); i++) {
     sumDistance += (a[i].x - b[i].x) * (a[i].x - b[i].x);
@@ -589,7 +589,7 @@ getDistance(vector<FloatCoordi>& a, vector<FloatCoordi>& b) {
 }
 
 static float
-getSecondNorm(vector<FloatCoordi>& a) {
+getSecondNorm(vector<FloatPoint>& a) {
   float norm = 0;
   for(auto& coordi : a) {
     norm += coordi.x * coordi.x + coordi.y * coordi.y;
diff --git a/src/nesterovPlace.h b/src/nesterovPlace.h
index 1e8abe6..61a062c 100644
--- a/src/nesterovPlace.h
+++ b/src/nesterovPlace.h
@@ -1,7 +1,7 @@
 #ifndef __REPLACE_NESTEROV_PLACE__
 #define __REPLACE_NESTEROV_PLACE__
 
-#include "coordi.h"
+#include "point.h"
 #include <memory>
 #include <vector>
 
@@ -40,24 +40,24 @@ public:
   void doNesterovPlace();
 
   void updateCoordi(
-      std::vector<FloatCoordi>& coordi);
+      std::vector<FloatPoint>& coordi);
   void updateBins();
   void updateWireLength();
 
   void updateGradients(
-      std::vector<FloatCoordi>& sumGrads,
-      std::vector<FloatCoordi>& wireLengthGrads,
-      std::vector<FloatCoordi>& densityGrads );
+      std::vector<FloatPoint>& sumGrads,
+      std::vector<FloatPoint>& wireLengthGrads,
+      std::vector<FloatPoint>& densityGrads );
 
   void updateWireLengthCoef(float overflow);
 
   void updateInitialPrevSLPCoordi();
 
   float getStepLength(
-      std::vector<FloatCoordi>& prevCoordi_,
-      std::vector<FloatCoordi>& prevSumGrads_,
-      std::vector<FloatCoordi>& curCoordi_,
-      std::vector<FloatCoordi>& curSumGrads_ );
+      std::vector<FloatPoint>& prevCoordi_,
+      std::vector<FloatPoint>& prevSumGrads_,
+      std::vector<FloatPoint>& curCoordi_,
+      std::vector<FloatPoint>& curSumGrads_ );
 
   void updateNextIter();
   float getPhiCoef(float scaledDiffHpwl);
@@ -73,26 +73,26 @@ private:
   // SLP is Step Length Prediction.
   //
   // y_st, y_dst, y_wdst, w_pdst
-  std::vector<FloatCoordi> curSLPCoordi_;
-  std::vector<FloatCoordi> curSLPWireLengthGrads_;
-  std::vector<FloatCoordi> curSLPDensityGrads_;
-  std::vector<FloatCoordi> curSLPSumGrads_;
+  std::vector<FloatPoint> curSLPCoordi_;
+  std::vector<FloatPoint> curSLPWireLengthGrads_;
+  std::vector<FloatPoint> curSLPDensityGrads_;
+  std::vector<FloatPoint> curSLPSumGrads_;
 
   // y0_st, y0_dst, y0_wdst, y0_pdst
-  std::vector<FloatCoordi> nextSLPCoordi_;
-  std::vector<FloatCoordi> nextSLPWireLengthGrads_;
-  std::vector<FloatCoordi> nextSLPDensityGrads_;
-  std::vector<FloatCoordi> nextSLPSumGrads_;
+  std::vector<FloatPoint> nextSLPCoordi_;
+  std::vector<FloatPoint> nextSLPWireLengthGrads_;
+  std::vector<FloatPoint> nextSLPDensityGrads_;
+  std::vector<FloatPoint> nextSLPSumGrads_;
 
   // z_st, z_dst, z_wdst, z_pdst
-  std::vector<FloatCoordi> prevSLPCoordi_;
-  std::vector<FloatCoordi> prevSLPWireLengthGrads_;
-  std::vector<FloatCoordi> prevSLPDensityGrads_;
-  std::vector<FloatCoordi> prevSLPSumGrads_;
+  std::vector<FloatPoint> prevSLPCoordi_;
+  std::vector<FloatPoint> prevSLPWireLengthGrads_;
+  std::vector<FloatPoint> prevSLPDensityGrads_;
+  std::vector<FloatPoint> prevSLPSumGrads_;
 
   // x_st and x0_st
-  std::vector<FloatCoordi> curCoordi_;
-  std::vector<FloatCoordi> nextCoordi_;
+  std::vector<FloatPoint> curCoordi_;
+  std::vector<FloatPoint> nextCoordi_;
 
   float wireLengthGradSum_;
   float densityGradSum_;
diff --git a/src/plot.cpp b/src/plot.cpp
index d4cdef7..a612849 100644
--- a/src/plot.cpp
+++ b/src/plot.cpp
@@ -160,7 +160,7 @@ int PlotEnv::GetTotalImageHeight() {
   return imageHeight + 2 * yMargin;
 }
 
-int PlotEnv::GetX(FloatCoordi &coord) {
+int PlotEnv::GetX(FloatPoint &coord) {
   return (coord.x - pb_->die().dieLx()) * unitX + xMargin;
 }
 
@@ -168,7 +168,7 @@ int PlotEnv::GetX(float coord) {
   return (coord - pb_->die().dieLx()) * unitX + xMargin;
 }
 
-int PlotEnv::GetY(FloatCoordi &coord) {
+int PlotEnv::GetY(FloatPoint &coord) {
   return (origHeight - (coord.y - pb_->die().dieLy())) * unitY + yMargin;
 }
 
diff --git a/src/plot.h b/src/plot.h
index f92f0cf..73b66a5 100644
--- a/src/plot.h
+++ b/src/plot.h
@@ -5,7 +5,7 @@
 
 #include <vector>
 #include <memory>
-#include "coordi.h"
+#include "point.h"
 
 // 
 // The following structure/header will be removed.
@@ -87,9 +87,9 @@ class PlotEnv {
   void InitCellColors(std::string colorFile);
   int GetTotalImageWidth();
   int GetTotalImageHeight();
-  int GetX(FloatCoordi &coord);
+  int GetX(FloatPoint &coord);
   int GetX(float coord);
-  int GetY(FloatCoordi &coord);
+  int GetY(FloatPoint &coord);
   int GetY(float coord);
   
   void DrawModule(CImgObj *img, const unsigned char color[], float opacity);
diff --git a/src/point.cpp b/src/point.cpp
new file mode 100644
index 0000000..17ff0e9
--- /dev/null
+++ b/src/point.cpp
@@ -0,0 +1,17 @@
+#include "point.h"
+
+namespace replace {
+
+FloatPoint::FloatPoint() : x(0), y(0) {}
+FloatPoint::FloatPoint(float inputX, float inputY) {
+  x = inputX; 
+  y = inputY;
+}
+
+IntPoint::IntPoint() : x(0), y(0) {}
+IntPoint::IntPoint(int inputX, int inputY) {
+  x = inputX;
+  y = inputY;
+}
+}
+
diff --git a/src/coordi.h b/src/point.h
similarity index 54%
rename from src/coordi.h
rename to src/point.h
index cbd09a6..61b2a73 100644
--- a/src/coordi.h
+++ b/src/point.h
@@ -3,20 +3,20 @@
 
 namespace replace {
 
-class FloatCoordi {
+class FloatPoint {
   public:
   float x;
   float y;
-  FloatCoordi();
-  FloatCoordi(float x, float y);
+  FloatPoint();
+  FloatPoint(float x, float y);
 };
 
-class IntCoordi {
+class IntPoint {
   public:
   int x;
   int y;
-  IntCoordi();
-  IntCoordi(int x, int y);
+  IntPoint();
+  IntPoint(int x, int y);
 };
 }