diff --git a/CMakeLists.txt b/CMakeLists.txt
index 82b9289..1ec41fe 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,25 +12,20 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(SOURCE_DIR "${PROJECT_SOURCE_DIR}/src")
 set(INCLUDE_DIR "${PROJECT_SOURCE_DIR}/inc")
 
-file(GLOB SOURCES "${SOURCE_DIR}/*.cpp$")
-file(GLOB HEADERS "${SOURCE_INCLUDE}/*.hpp$")
+file(GLOB SOURCES "${SOURCE_DIR}/*.cpp")
+file(GLOB HEADERS "${INCLUDE_DIR}/*.hpp")
 
 #include_directories(
 # ${GUROBI_INCLUDE_DIRS}
 #)
 
-message(${SOURCE_DIR})
-
 aux_source_directory(${SOURCE_DIR} src)
 aux_source_directory(${INCLUDE_DIR} inc)
 
-
-add_executable(Solver
-   src/main.cpp src/solver.cpp inc/solver.hpp
-  )
+add_executable(Solver ${SOURCES} ${HEADERS})
 
 #target_link_libraries(Solver 
-# ${GUROBI_LIBRARIES}
+#  ${GUROBI_LIBRARIES}
 #)
 
 target_include_directories(Solver PRIVATE ${SOURCE_DIR} ${INCLUDE_DIR})
diff --git a/inc/common.hpp b/inc/common.hpp
new file mode 100644
index 0000000..5dc0dbd
--- /dev/null
+++ b/inc/common.hpp
@@ -0,0 +1,163 @@
+#pragma once
+#include <vector>
+
+#define MDL_MINIMIZE 1
+#define MDL_MAXIMIZE -1
+
+#define	LOADED	0
+#define	OPTIMAL	1
+#define	INFEASIBLE	2
+#define	INF_OR_UNBD	3
+#define	UNBOUNDED	4
+#define	CUTOFF	5
+#define	ITERATION_LIMIT	6
+#define	NODE_LIMIT	7
+#define	TIME_LIMIT	8
+#define	SOLUTION_LIMIT	9
+#define	INTERRUPTED	10
+#define	NUMERIC	11
+#define	SUBOPTIMAL	12
+#define	INPROGRESS	13
+#define	USER_OBJ_LIMIT	14
+#define	WORK_LIMIT	15
+#define	MEM_LIMIT	16
+#define	PIVOT	17
+
+namespace sv {
+	using matrix = std::vector<std::vector<double>>;
+	using rtn = int;
+	class Expr;
+	class Var;
+
+	enum class IntAttr {
+		NumConstrs,
+		NumVars,
+		NumIntVars,
+		NumBinVars,
+		ModelSense,
+		IsMIP,
+		IsMultiObj,
+		Status,
+		SolCount,
+		Lazy,
+		NumObj,
+		NumCol
+	};
+
+	enum class DoubleAttr {
+		Runtime,
+		Work,
+		ObjCon,
+		LB,
+		UB,
+		Obj,
+		Start,
+		RHS,
+		Coeff,
+		MaxCoeff,
+		MinCoeff,
+		MaxBound,
+		MinBound,
+		ObjVal,
+		MIPGap,
+		IterCount,
+		NodeCount,
+		X,
+		Slack,
+	};
+
+	enum class StringAttr {
+		ModelName,
+		VarName,
+		ConstrName,
+		QCName,
+		GenConstrName,
+		ObjNName,
+		ScenNName,
+		BatchID,
+		VTag,
+		CTag,
+		QCTag,
+		BatchErrorMessage
+	};
+
+	enum class ConstrOper {
+		LESS_EQUAL,
+		GREATER_EQUAL,
+		EQUAL
+	};
+
+	class Var {
+	public:
+		Var(double coef = 1) :col(0), val(0), coeffs(coef) {};
+		double get(DoubleAttr attr);
+		int get(IntAttr attr);
+		friend class Model;
+		friend class Expr;
+	private:
+		double coeffs;
+		double val;
+		int col;
+	};
+
+	Expr operator+(const Expr& x, const Expr& y);
+	Expr operator-(const Expr& x, const Expr& y);
+	Expr operator+(const Expr& x);
+	Expr operator+(Var x, Var y);
+	Expr operator+(Var x, double a);
+	Expr operator+(double a, Var x);
+	Expr operator-(const Expr& x);
+	Expr operator-(Var x);
+	Expr operator-(Var x, Var y);
+	Expr operator-(Var x, double a);
+	Expr operator-(double a, Var x);
+	Expr operator*(double a, Var x);
+	Expr operator*(Var x, double a);
+	Expr operator*(const Expr& x, double a);
+	Expr operator*(double a, const Expr& x);
+	Expr operator/(Var x, double a);
+	Expr operator/(const Expr& x, double a);
+
+
+	class Expr
+	{
+	private:
+		double constant;
+		std::vector<double> coeffs;
+		std::vector<Var> vars;
+
+	public:
+		Expr(const Expr& expr) = default;
+		Expr(double constant = 0.0);
+		Expr(Var var, double coeff = 1.0);
+
+		friend class Model;
+
+		friend Expr operator+(const Expr& x, const Expr& y);
+		friend Expr operator+(const Expr& x);
+		friend Expr operator+(Var x, Var y);
+		friend Expr operator+(Var x, double a);
+		friend Expr operator+(double a, Var x);
+		friend Expr operator-(const Expr& x, const Expr& y);
+		friend Expr operator-(const Expr& x);
+		friend Expr operator-(Var x);
+		friend Expr operator-(Var x, Var y);
+		friend Expr operator-(Var x, double a);
+		friend Expr operator-(double a, Var x);
+		friend Expr operator*(double a, Var x);
+		friend Expr operator*(Var x, double a);
+		friend Expr operator*(const Expr& x, double a);
+		friend Expr operator*(double a, const Expr& x);
+		friend Expr operator/(Var x, double a);
+		friend Expr operator/(const Expr& x, double a);
+
+
+		Expr operator=(const Expr& rhs);
+		void operator+=(const Expr& expr);
+		void operator-=(const Expr& expr);
+		void operator*=(double mult);
+		void operator/=(double a);
+		Expr operator+(const Expr& rhs);
+		Expr operator-(const Expr& rhs);
+	};
+}
diff --git a/inc/node.hpp b/inc/node.hpp
new file mode 100644
index 0000000..7c06824
--- /dev/null
+++ b/inc/node.hpp
@@ -0,0 +1,5 @@
+#pragma once
+
+class Node {
+
+};
\ No newline at end of file
diff --git a/inc/solver.hpp b/inc/solver.hpp
index 0fdd6cb..ca974c7 100644
--- a/inc/solver.hpp
+++ b/inc/solver.hpp
@@ -1,327 +1,34 @@
 #pragma once
-#include <vector>
-using std::vector;
+#include <common.hpp>
 
-class Expr;
-class Var;
+namespace sv {
 
-#define MDL_MINIMIZE 1
-#define MDL_MAXIMIZE -1
+	class Model
+	{
+	public:
+		Model();
+		Var* addVars(int col);
+		void addConstr(const Expr& expr, ConstrOper sense, double rhs);
+		void setObjective(Expr obje, int sense = MDL_MAXIMIZE);
+		void print();
+		rtn optimize();
+		double get(DoubleAttr attr);
+		int get(IntAttr attr);
+	private:
+		double _simplex();
+		rtn _pivot(std::pair<size_t, size_t>& p);
+		void _gaussian(std::pair<size_t, size_t> p);
 
-Expr operator+(const Expr& x, const Expr& y);
-Expr operator-(const Expr& x, const Expr& y);
-Expr operator+(const Expr& x);
-Expr operator+(Var x, Var y);
-Expr operator+(Var x, double a);
-Expr operator+(double a, Var x);
-Expr operator-(const Expr& x);
-Expr operator-(Var x);
-Expr operator-(Var x, Var y);
-Expr operator-(Var x, double a);
-Expr operator-(double a, Var x);
-Expr operator*(double a, Var x);
-Expr operator*(Var x, double a);
-Expr operator*(const Expr& x, double a);
-Expr operator*(double a, const Expr& x);
-Expr operator/(Var x, double a);
-Expr operator/(const Expr& x, double a);
+		Var* vars;
 
-typedef vector<vector<double>> Matrix;
-
-enum class Rtn {
-	LOADED,
-	OPTIMAL,
-	INFEASIBLE,
-	INF_OR_UNBD,
-	UNBOUNDED,
-	CUTOFF,
-	ITERATION_LIMIT,
-	NODE_LIMIT,
-	TIME_LIMIT,
-	SOLUTION_LIMIT,
-	INTERRUPTED,
-	NUMERIC,
-	SUBOPTIMAL,
-	INPROGRESS,
-	USER_OBJ_LIMIT,
-	WORK_LIMIT,
-	MEM_LIMIT,
-	PIVOT,
-};
-
-enum class IntAttr {
-	NumConstrs,
-	NumVars,
-	NumSOS,
-	NumQConstrs,
-	NumGenConstrs,
-	NumNZs,
-	NumQNZs,
-	NumQCNZs,
-	NumIntVars,
-	NumBinVars,
-	NumPWLObjVars,
-	ModelSense,
-	IsMIP,
-	IsQP,
-	IsQCP,
-	IsMultiObj,
-	Status,
-	ConcurrentWinMethod,
-	SolCount,
-	BarIterCount,
-	VBasis,
-	CBasis,
-	PWLObjCvx,
-	BranchPriority,
-	VarPreStat,
-	BoundVioIndex,
-	BoundSVioIndex,
-	ConstrVioIndex,
-	ConstrSVioIndex,
-	ConstrResidualIndex,
-	ConstrSResidualIndex,
-	DualVioIndex,
-	DualSVioIndex,
-	DualResidualIndex,
-	DualSResidualIndex,
-	ComplVioIndex,
-	IntVioIndex,
-	IISMinimal,
-	IISLB,
-	IISUB,
-	IISConstr,
-	IISSOS,
-	IISQConstr,
-	IISGenConstr,
-	IISLBForce,
-	IISUBForce,
-	IISConstrForce,
-	IISSOSForce,
-	IISQConstrForce,
-	IISGenConstrForce,
-	TuneResultCount,
-	Lazy,
-	VarHintPri,
-	ObjNPriority,
-	NumObj,
-	GenConstrType,
-	NumStart,
-	Partition,
-	LicenseExpiration,
-	NumScenarios,
-	FuncPieces,
-	BatchErrorCode,
-	BatchStatus,
-	Fingerprint,
-	PoolIgnore,
-	FuncNonlinear,
-	ModelColumn
-};
-
-enum class DoubleAttr{
-	Runtime,
-	Work,
-	ObjCon,
-	LB,
-	UB,
-	Obj,
-	Start,
-	PreFixVal,
-	RHS,
-	QCRHS,
-	Coeff,
-	MaxCoeff,
-	MinCoeff,
-	MaxBound,
-	MinBound,
-	MaxObjCoeff,
-	MinObjCoeff,
-	MaxRHS,
-	MinRHS,
-	MaxQCRHS,
-	MinQCRHS,
-	MaxQCCoeff,
-	MinQCCoeff,
-	MaxQCLCoeff,
-	MinQCLCoeff,
-	MaxQObjCoeff,
-	MinQObjCoeff,
-	ObjVal,
-	ObjBound,
-	ObjBoundC,
-	MIPGap,
-	IterCount,
-	NodeCount,
-	X,
-	RC,
-	Pi,
-	QCPi,
-	Slack,
-	QCSlack,
-	MaxVio,
-	BoundVio,
-	BoundSVio,
-	BoundVioSum,
-	BoundSVioSum,
-	ConstrVio,
-	ConstrSVio,
-	ConstrVioSum,
-	ConstrSVioSum,
-	ConstrResidual,
-	ConstrSResidual,
-	ConstrResidualSum,
-	ConstrSResidualSum,
-	DualVio,
-	DualSVio,
-	DualVioSum,
-	DualSVioSum,
-	DualResidual,
-	DualSResidual,
-	DualResidualSum,
-	DualSResidualSum,
-	ComplVio,
-	ComplVioSum,
-	IntVio,
-	IntVioSum,
-	Kappa,
-	KappaExact,
-	SAObjLow,
-	SAObjUp,
-	SALBLow,
-	SALBUp,
-	SARHSLow,
-	SAUBLow,
-	SAUBUp,
-	SARHSUp,
-	Xn,
-	FarkasProof,
-	FarkasDual,
-	UnbdRay,
-	PStart,
-	DStart,
-	BarX,
-	VarHintVal,
-	ObjN,
-	ObjNCon,
-	ObjNWeight,
-	ObjNRelTol,
-	ObjNAbsTol,
-	ObjNVal,
-	OpenNodeCount,
-	PoolObjBound,
-	PoolObjVal,
-	ScenNLB,
-	ScenNUB,
-	ScenNObj,
-	ScenNRHS,
-	ScenNX,
-	ScenNObjBound,
-	ScenNObjVal,
-	FuncPieceError,
-	FuncPieceLength,
-	FuncPieceRatio,
-	DNumNZs
-};
-
-enum class StringAttr {
-	ModelName,
-	VarName,
-	ConstrName,
-	QCName,
-	GenConstrName,
-	ObjNName,
-	ScenNName,
-	BatchID,
-	VTag,
-	CTag,
-	QCTag,
-	BatchErrorMessage
-};
-
-enum class ConstrOper {
-	LESS_EQUAL,
-	GREATER_EQUAL,
-	EQUAL
-};
-
-class Var {
-public:
-	Var(double coef = 1) :col(0), val(0), coeffs(coef) {};
-	double get(DoubleAttr attr);
-	int get(IntAttr attr);
-	friend class Model;
-	friend class Expr;
-private:
-	double coeffs;
-	double val;
-	int col;
-};
-
-class Expr
-{
-private:
-	double constant;
-	std::vector<double> coeffs;
-	std::vector<Var> vars;
-
-public:
-	Expr(const Expr& expr) = default;
-	Expr(double constant = 0.0);
-	Expr(Var var, double coeff = 1.0);
-
-	friend class Model;
-
-	friend Expr operator+(const Expr& x, const Expr& y);
-	friend Expr operator+(const Expr& x);
-	friend Expr operator+(Var x, Var y);
-	friend Expr operator+(Var x, double a);
-	friend Expr operator+(double a, Var x);
-	friend Expr operator-(const Expr& x, const Expr& y);
-	friend Expr operator-(const Expr& x);
-	friend Expr operator-(Var x);
-	friend Expr operator-(Var x, Var y);
-	friend Expr operator-(Var x, double a);
-	friend Expr operator-(double a, Var x);
-	friend Expr operator*(double a, Var x);
-	friend Expr operator*(Var x, double a);
-	friend Expr operator*(const Expr& x, double a);
-	friend Expr operator*(double a, const Expr& x);
-	friend Expr operator/(Var x, double a);
-	friend Expr operator/(const Expr& x, double a);
+		matrix mt;
+		size_t cn, bn;
+		std::vector<int> basic;
+		rtn rtn_;
+		double res_;
+		int sense;
+	};
+}
 
 
-	Expr operator=(const Expr& rhs);
-	void operator+=(const Expr& expr);
-	void operator-=(const Expr& expr);
-	void operator*=(double mult);
-	void operator/=(double a);
-	Expr operator+(const Expr& rhs);
-	Expr operator-(const Expr& rhs);
-};
 
-class Model
-{
-public:
-	Model();
-	Var* addVars(int col);
-	void addConstr(const Expr& expr, ConstrOper sense, double rhs);
-	void setObjective(Expr obje, int sense = MDL_MAXIMIZE);
-	void print();
-	Rtn optimize();
-	double get(DoubleAttr attr);
-	int get(IntAttr attr);
-private:
-	double _simplex();
-	Rtn _pivot(std::pair<size_t, size_t>& p);
-	void _gaussian(std::pair<size_t, size_t> p);
-
-	Var* vars;
-
-	Matrix matrix;
-	size_t cn, bn;
-	vector<int> basic;
-	Rtn rtn;
-	double res;
-	int sense;
-};
\ No newline at end of file
diff --git a/src/common.cpp b/src/common.cpp
new file mode 100644
index 0000000..2869025
--- /dev/null
+++ b/src/common.cpp
@@ -0,0 +1,225 @@
+#include "common.hpp"
+using namespace sv;
+
+double Var::get(DoubleAttr attr)
+{
+	switch (attr) {
+	case DoubleAttr::Coeff:
+		return coeffs;
+	case DoubleAttr::X:
+		return val;
+	}
+	return -1;
+}
+
+int Var::get(IntAttr attr)
+{
+	return col;
+}
+
+Expr sv::operator+(const Expr& x, const Expr& y)
+{
+	Expr exp;
+	exp.coeffs.resize(std::max(x.coeffs.size(), y.coeffs.size()), 0);
+	for (int c = 0; c < exp.coeffs.size(); c++) {
+		if (c < x.coeffs.size() && c < y.coeffs.size()) {
+			exp.coeffs[c] = x.coeffs[c] + y.coeffs[c];
+		}
+		else {
+			exp.coeffs[c] = c < x.coeffs.size() ? x.coeffs[c] : y.coeffs[c];
+		}
+	}
+	exp.constant = x.constant + y.constant;
+	return exp;
+}
+
+Expr sv::operator+(const Expr& x)
+{
+	return x;
+}
+
+Expr sv::operator+(Var x, Var y)
+{
+	Expr exp;
+	exp.coeffs.resize(std::max(x.get(IntAttr::NumCol) + 1, y.get(IntAttr::NumCol) + 1), 0);
+	exp.coeffs[x.get(IntAttr::NumCol)] = x.get(DoubleAttr::Coeff);
+	exp.coeffs[y.get(IntAttr::NumCol)] = y.get(DoubleAttr::Coeff);
+	return exp;
+}
+
+Expr sv::operator+(Var x, double a)
+{
+	Expr exp;
+	exp.coeffs.resize(x.get(IntAttr::NumCol) + 1);
+	exp.constant = a;
+	return exp;
+}
+
+Expr sv::operator+(double a, Var x)
+{
+	return x + a;
+}
+
+Expr sv::operator-(const Expr& x, const Expr& y)
+{
+	Expr exp;
+	exp.coeffs.resize(std::max(x.coeffs.size(), y.coeffs.size()), 0);
+	for (int c = 0; c < exp.coeffs.size(); c++) {
+		if (c < x.coeffs.size() && c < y.coeffs.size()) {
+			exp.coeffs[c] = x.coeffs[c] - y.coeffs[c];
+		}
+		else {
+			exp.coeffs[c] = c < x.coeffs.size() ? x.coeffs[c] : y.coeffs[c];
+		}
+	}
+	exp.constant = x.constant + y.constant;
+	return exp;
+}
+
+Expr sv::operator-(const Expr& x)
+{
+	Expr expr(x);
+	for (int c = 0; c < expr.coeffs.size(); c++) {
+		expr.coeffs[c] = -expr.coeffs[c];
+	}
+	expr.constant = -expr.constant;
+	return expr;
+}
+
+Expr sv::operator-(Var x)
+{
+	return -Expr(x);
+}
+
+Expr sv::operator-(Var x, Var y)
+{
+	Expr exp;
+	exp.coeffs.resize(std::max(x.get(IntAttr::NumCol) + 1, y.get(IntAttr::NumCol) + 1), 0);
+	exp.coeffs[x.get(IntAttr::NumCol)] = x.get(DoubleAttr::Coeff);
+	exp.coeffs[y.get(IntAttr::NumCol)] = -y.get(DoubleAttr::Coeff);
+	return exp;
+}
+
+Expr sv::operator-(Var x, double a)
+{
+	return x - Var(a);
+}
+
+Expr sv::operator-(double a, Var x)
+{
+	return x - a;
+}
+
+Expr sv::operator*(double a, Var x)
+{
+	Expr exp;
+	exp.coeffs.resize(x.get(IntAttr::NumCol) + 1, 0);
+	exp.coeffs[x.get(IntAttr::NumCol)] = a * x.get(DoubleAttr::Coeff);
+	return exp;
+}
+
+Expr sv::operator*(Var x, double a)
+{
+	return a * x;
+}
+
+Expr sv::operator*(const Expr& x, double a)
+{
+	Expr exp = x;
+	for (int c = 0; c < exp.coeffs.size(); c++) {
+		exp.coeffs[c] *= a;
+	}
+	exp.constant *= a;
+	return exp;
+}
+
+Expr sv::operator*(double a, const Expr& x)
+{
+	return x * a;
+}
+
+Expr sv::operator/(Var x, double a)
+{
+	return Expr(x) / a;
+}
+
+Expr sv::operator/(const Expr& x, double a)
+{
+	Expr exp = x;
+	for (int c = 0; c < exp.coeffs.size(); c++) {
+		exp.coeffs[c] /= a;
+	}
+	exp.constant /= a;
+	return exp;
+}
+
+Expr::Expr(double constant)
+	:constant(constant)
+{
+}
+
+Expr::Expr(Var var, double coeff)
+{
+	this->coeffs.resize(var.col + 1);
+	this->coeffs[var.col] = coeff;
+	this->constant = 0;
+}
+
+Expr Expr::operator=(const Expr& rhs)
+{
+	return *this;
+}
+
+void Expr::operator+=(const Expr& expr)
+{
+	coeffs.resize(std::max(coeffs.size(), expr.coeffs.size()));
+	for (int c = 0; c < expr.coeffs.size(); c++) {
+		coeffs[c] += expr.coeffs[c];
+	}
+	constant += expr.constant;
+}
+
+void Expr::operator-=(const Expr& expr)
+{
+	coeffs.resize(std::max(coeffs.size(), expr.coeffs.size()));
+	for (int c = 0; c < expr.coeffs.size(); c++) {
+		coeffs[c] -= expr.coeffs[c];
+	}
+	constant -= expr.constant;
+}
+
+void Expr::operator*=(double mult)
+{
+	for (int c = 0; c < coeffs.size(); c++) {
+		coeffs[c] *= mult;
+	}
+	constant *= mult;
+}
+
+void Expr::operator/=(double a)
+{
+	for (int c = 0; c < coeffs.size(); c++) {
+		coeffs[c] /= a;
+	}
+	constant /= a;
+}
+
+Expr Expr::operator+(const Expr& rhs)
+{
+	coeffs.resize(std::max(coeffs.size(), rhs.coeffs.size()));
+	for (int c = 0; c < rhs.coeffs.size(); c++) {
+		coeffs[c] += rhs.coeffs[c];
+	}
+	constant += rhs.constant;
+	return *this;
+}
+
+Expr Expr::operator-(const Expr& rhs)
+{
+	coeffs.resize(std::max(coeffs.size(), rhs.coeffs.size()));
+	for (int c = 0; c < rhs.coeffs.size(); c++) {
+		coeffs[c] -= rhs.coeffs[c];
+	}
+	constant -= rhs.constant;
+	return *this;
+}
diff --git a/src/main.cpp b/src/main.cpp
index 5430942..37e8956 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -4,6 +4,7 @@
 #include "solver.hpp"
 
 using namespace std;
+using namespace sv;
 
 int main(int argc, char* argv[])
 {
@@ -18,16 +19,16 @@ int main(int argc, char* argv[])
 	mdl.setObjective(vars[0] + 2 * vars[1], MDL_MAXIMIZE);
 
 	switch(mdl.optimize()) {
-	case Rtn::OPTIMAL:			
+	case OPTIMAL:			
 		cout << "OPTIMAL SOLUTION: " << mdl.get(DoubleAttr::Obj) << endl; 
 		for (int i = 0; i < mdl.get(IntAttr::NumVars); i++) {
 			cout << "var[" << i << "] : " << vars[i].get(DoubleAttr::X) << endl;
 		}
 		break;
-	case Rtn::INFEASIBLE:	
+	case INFEASIBLE:	
 		cout << "INFEASIBLE MODEL" << endl;					
 		break;
-	case Rtn::UNBOUNDED:	
+	case UNBOUNDED:	
 		cout << "UNBOUNDED SOLUTION" << endl;			
 		break;
 	default:
diff --git a/src/solver.cpp b/src/solver.cpp
index b437bc9..4953777 100644
--- a/src/solver.cpp
+++ b/src/solver.cpp
@@ -1,148 +1,17 @@
 #include "solver.hpp"
+#include "common.hpp"
+
 #include <iostream>
 #include <cassert>
 #include <algorithm>
 
+using namespace sv;
+
 using std::make_pair;
 using std::pair;
 using std::cout;
 using std::endl;
-
-Expr operator+(const Expr& x, const Expr& y)
-{
-	Expr exp;
-	exp.coeffs.resize(std::max(x.coeffs.size(), y.coeffs.size()), 0);
-	for (int c = 0; c < exp.coeffs.size(); c++) {
-		if (c < x.coeffs.size() && c < y.coeffs.size()) {
-			exp.coeffs[c] = x.coeffs[c] + y.coeffs[c];
-		}
-		else {
-			exp.coeffs[c]= c < x.coeffs.size()? x.coeffs[c] : y.coeffs[c];
-		}
-	}
-	exp.constant = x.constant + y.constant;
-	return exp;
-}
-
-Expr operator+(const Expr& x)
-{
-	return x;
-}
-
-Expr operator+(Var x, Var y)
-{
-	Expr exp;
-	exp.coeffs.resize(std::max(x.get(IntAttr::ModelColumn) + 1, y.get(IntAttr::ModelColumn) + 1), 0);
-	exp.coeffs[x.get(IntAttr::ModelColumn)] = x.get(DoubleAttr::Coeff);
-	exp.coeffs[y.get(IntAttr::ModelColumn)] = y.get(DoubleAttr::Coeff);
-	return exp;
-}
-
-Expr operator+(Var x, double a)
-{
-	Expr exp;
-	exp.coeffs.resize(x.get(IntAttr::ModelColumn) + 1);
-	exp.constant = a;
-	return exp;
-}
-
-Expr operator+(double a, Var x)
-{
-	return x + a;
-}
-
-Expr operator-(const Expr& x, const Expr& y)
-{
-	Expr exp;
-	exp.coeffs.resize(std::max(x.coeffs.size(), y.coeffs.size()), 0);
-	for (int c = 0; c < exp.coeffs.size(); c++) {
-		if (c < x.coeffs.size() && c < y.coeffs.size()) {
-			exp.coeffs[c] = x.coeffs[c] - y.coeffs[c];
-		}
-		else {
-			exp.coeffs[c] = c < x.coeffs.size() ? x.coeffs[c] : y.coeffs[c];
-		}
-	}
-	exp.constant = x.constant + y.constant;
-	return exp;
-}
-
-Expr operator-(const Expr& x)
-{
-	Expr expr(x);
-	for (int c = 0; c < expr.coeffs.size(); c++) {
-		expr.coeffs[c] = -expr.coeffs[c];
-	}
-	expr.constant = -expr.constant;
-	return expr;
-}
-
-Expr operator-(Var x)
-{
-	return -Expr(x);
-}
-
-Expr operator-(Var x, Var y)
-{
-	Expr exp;
-	exp.coeffs.resize(std::max(x.get(IntAttr::ModelColumn) + 1, y.get(IntAttr::ModelColumn) + 1), 0);
-	exp.coeffs[x.get(IntAttr::ModelColumn)] = x.get(DoubleAttr::Coeff);
-	exp.coeffs[y.get(IntAttr::ModelColumn)] = -y.get(DoubleAttr::Coeff);
-	return exp;
-}
-
-Expr operator-(Var x, double a)
-{
-	return x - Var(a);
-}
-
-Expr operator-(double a, Var x)
-{
-	return x - a;
-}
-
-Expr operator*(double a, Var x)
-{
-	Expr exp;
-	exp.coeffs.resize(x.get(IntAttr::ModelColumn) + 1, 0);
-	exp.coeffs[x.get(IntAttr::ModelColumn)] = a * x.get(DoubleAttr::Coeff);
-	return exp;
-}
-
-Expr operator*(Var x, double a)
-{
-	return a * x;
-}
-
-Expr operator*(const Expr& x, double a)
-{
-	Expr exp = x;
-	for (int c = 0; c < exp.coeffs.size(); c++) {
-		exp.coeffs[c] *= a;
-	}
-	exp.constant *= a;
-	return exp;
-}
-
-Expr operator*(double a, const Expr& x)
-{
-	return x * a;
-}
-
-Expr operator/(Var x, double a)
-{
-	return Expr(x) / a;
-}
-
-Expr operator/(const Expr& x, double a)
-{
-	Expr exp = x;
-	for (int c = 0; c < exp.coeffs.size(); c++) {
-		exp.coeffs[c] /= a;
-	}
-	exp.constant /= a;
-	return exp;
-}
+using std::vector;
 
 Model::Model():
 	cn(0),
@@ -168,15 +37,14 @@ Var* Model::addVars(int num)
 
 void Model::addConstr(const Expr& expr, ConstrOper sense, double rhs)
 {
-	
 	if (sense == ConstrOper::LESS_EQUAL) {
-		matrix.push_back(vector<double>(1, rhs - expr.constant));
-		matrix.back().insert(matrix.back().end(), expr.coeffs.begin(), expr.coeffs.end());
+		mt.push_back(vector<double>(1, rhs - expr.constant));
+		mt.back().insert(mt.back().end(), expr.coeffs.begin(), expr.coeffs.end());
 	}
 	else if (sense == ConstrOper::GREATER_EQUAL) {
-		matrix.push_back(vector<double>(1, expr.constant - rhs));
+		mt.push_back(vector<double>(1, expr.constant - rhs));
 		for (int coeff : expr.coeffs) {
-			matrix.back().push_back(-coeff);
+			mt.back().push_back(-coeff);
 		}
 	}
 	else {
@@ -184,8 +52,8 @@ void Model::addConstr(const Expr& expr, ConstrOper sense, double rhs)
 		addConstr(expr, ConstrOper::GREATER_EQUAL, rhs);
 	}
 	
-	for (int c = matrix.back().size(); c <= cn; c++) {
-		matrix.back().push_back(0);
+	for (int c = mt.back().size(); c <= cn; c++) {
+		mt.back().push_back(0);
 	}
 }
 
@@ -193,47 +61,48 @@ void Model::setObjective(Expr obje, int _sense)
 {
 	assert(_sense == 1 || _sense == -1);
 	if (sense == 0) {
-		matrix.insert(matrix.begin(), obje.coeffs);
-		matrix.front().insert(matrix.front().begin(), -obje.constant);
+		mt.insert(mt.begin(), obje.coeffs);
+		mt.front().insert(mt.front().begin(), -obje.constant);
 		for (int c = obje.coeffs.size() + 1; c <= cn; c++) {
-			matrix.front().push_back(0);
+			mt.front().push_back(0);
 		}
 	}
 	else {
-		matrix.front().front() = -obje.constant;
-		for (int c = 0; c < obje.coeffs.size(); c++) {
-			matrix.front()[c + 1] = obje.coeffs[c];
+		mt.front().front() = -obje.constant;
+		for (int c = 0; c < cn; c++) {
+			if (c < obje.coeffs.size()) {
+				mt.front()[c + 1] = obje.coeffs[c];
+			}
+			else {
+				mt.front()[c] = 0;
+			}
 		}
-		for (int c = obje.coeffs.size() + 1; c <= cn; c++) {
-			matrix.front()[c] = 0;
-		}
-
 	}
 	sense = _sense;
 }
 
 void Model::print()
 {
-	for (size_t i = 0; i < matrix.size(); i++) {
-		for (size_t j = 0; j < matrix[0].size(); j++) {
-			cout << matrix[i][j] << "\t";
+	for (size_t i = 0; i < mt.size(); i++) {
+		for (size_t j = 0; j < mt[0].size(); j++) {
+			cout << mt[i][j] << "\t";
 		}
 		cout << endl;
 	}
 }
 
-Rtn Model::optimize()
+rtn Model::optimize()
 {
-	bn = matrix.size();
+	bn = mt.size();
 	for (int row = 1; row < bn; row++) {
-		matrix.front().push_back(0);
+		mt.front().push_back(0);
 		for (int col = 1; col < bn; col++) {
-			matrix[row].push_back(col == row ? 1 : 0);
+			mt[row].push_back(col == row ? 1 : 0);
 		}
 	}
-	cn = matrix.front().size();
+	cn = mt.front().size();
 	for (int i = 0; i < cn; i++) {
-		matrix.front()[i] = sense * matrix.front()[i];
+		mt.front()[i] = sense * mt.front()[i];
 	}
 	
 	for (size_t i = 1; i < bn; i++) {
@@ -243,7 +112,7 @@ Rtn Model::optimize()
 	// === 判断初始解是否为可行解 ===
 	bool initial_feasible = true;
 	for (int row = 1; row < bn; row++) {
-		if (matrix[row].front() < 0) {
+		if (mt[row].front() < 0) {
 			initial_feasible = false;
 			break;
 		}
@@ -251,29 +120,29 @@ Rtn Model::optimize()
 
 	// === 构造初始可行解 === 
 	if (!initial_feasible) {
-		vector<double> coeff = matrix.front();
-		matrix.front() = vector<double>(cn, .0);
-		matrix.front().push_back(1);
+		vector<double> coeff = mt.front();
+		mt.front() = vector<double>(cn, .0);
+		mt.front().push_back(1);
 		pair<size_t, size_t> t = { -1 ,cn };
 
 		for (int row = 1; row < bn; row++) {
-			matrix[row].push_back(-1);
-			if (t.first == -1 || matrix[row].front() < matrix[t.first].front()) {
+			mt[row].push_back(-1);
+			if (t.first == -1 || mt[row].front() < mt[t.first].front()) {
 				t.first = row;
 			}
 		}
 
 		_gaussian(t);
 		if (fabs(_simplex()) > 1e-10) {
-			rtn = Rtn::INFEASIBLE;
-			return rtn;
+			rtn_ = INFEASIBLE;
+			return rtn_;
 		}
 
 		// if the x0 in B, we should pivot it.
 		auto iter = find(basic.begin(), basic.end(), cn);
 		if (iter != basic.end()) {
-			for (int col = 1; col < matrix.front().size(); col++) {
-				if (fabs(matrix.front()[col]) > 1e-10) {
+			for (int col = 1; col < mt.front().size(); col++) {
+				if (fabs(mt.front()[col]) > 1e-10) {
 					t = make_pair(iter - basic.begin() + 1, col);
 					_gaussian(t);
 					break;
@@ -282,33 +151,33 @@ Rtn Model::optimize()
 		}
 
 		for (int row = 0; row < bn; row++) {
-			matrix[row].pop_back();
+			mt[row].pop_back();
 		}
 
 		// recover the coefficient line
 		for (int col = 0; col < cn; col++) {
-			matrix.front()[col] = coeff[col];
+			mt.front()[col] = coeff[col];
 		}
 		for (int row = 1; row <= basic.size(); row++) {
-			int norm = matrix.front()[basic[row - 1]];
+			int norm = mt.front()[basic[row - 1]];
 			for (int col = 0; col < cn; col++) {
-				matrix.front()[col] -= norm * matrix[row][col];
+				mt.front()[col] -= norm * mt[row][col];
 			}
 		}
 	}
 
-	res = -sense * _simplex();
+	res_ = -sense * _simplex();
 	for (int row = 1; row < bn; row++) {
 		if (basic[row - 1] - 1 < cn - bn) {
-			vars[basic[row - 1] - 1].val = matrix[row].front();
+			vars[basic[row - 1] - 1].val = mt[row].front();
 		}
 	}
-	return rtn;
+	return rtn_;
 }
 
 double Model::get(DoubleAttr attr)
 {
-	return res;
+	return res_;
 }
 
 int Model::get(IntAttr attr)
@@ -320,20 +189,20 @@ double Model::_simplex()
 {
 	pair<size_t, size_t> t;
 	while (1) {
-		rtn = _pivot(t);
-		if (rtn == Rtn::OPTIMAL || rtn == Rtn::UNBOUNDED) {
+		rtn_ = _pivot(t);
+		if (rtn_ == OPTIMAL || rtn_ == UNBOUNDED) {
 			break;
 		}
 		_gaussian(t);
 	}
-	return matrix.front().front();
+	return mt.front().front();
 }
 
-Rtn Model::_pivot(pair<size_t, size_t>& p)
+rtn Model::_pivot(pair<size_t, size_t>& p)
 {
 	p = make_pair(0, 0);
 	double cmin = INT_MAX;
-	vector<double> coef = matrix.front();
+	vector<double> coef = mt.front();
 
 	// === 非主轴元素中找最小值 ===
 	for (size_t i = 1; i < coef.size(); i++) {
@@ -343,29 +212,29 @@ Rtn Model::_pivot(pair<size_t, size_t>& p)
 		}
 	}
 	if (cmin >= 0) {
-		return Rtn::OPTIMAL;
+		return OPTIMAL;
 	}
 	double bmin = INT_MAX;
 	for (size_t row = 1; row < bn; row++) {
-		double tmp = matrix[row].front() / matrix[row][p.second];
-		if (matrix[row][p.second] > 0 && bmin > tmp) {
+		double tmp = mt[row].front() / mt[row][p.second];
+		if (mt[row][p.second] > 0 && bmin > tmp) {
 			bmin = tmp;
 			p.first = row;
 		}
 	}
 
 	if (abs(bmin - INT_MAX) < 1e-10) {
-		return Rtn::UNBOUNDED;
+		return UNBOUNDED;
 	}
 
 	for (auto iter = basic.begin(); iter != basic.end(); iter++) {
-		if (matrix[p.first][*iter] != 0) {
+		if (mt[p.first][*iter] != 0) {
 			*iter = p.second;
 			break;
 		}
 	}
 	assert(basic[p.first - 1] == p.second);
-	return Rtn::PIVOT;
+	return PIVOT;
 }
 
 void Model::_gaussian(pair<size_t, size_t> p)
@@ -373,9 +242,9 @@ void Model::_gaussian(pair<size_t, size_t> p)
 	size_t x = p.first, y = p.second;
 
 	// === 主行归一化 ===
-	double norm = matrix[x][y];
-	for (size_t col = 0; col < matrix[x].size(); col++) {
-		matrix[x][col] /= norm;
+	double norm = mt[x][y];
+	for (size_t col = 0; col < mt[x].size(); col++) {
+		mt[x][col] /= norm;
 	}
 
 	// === 其余行变换 ===
@@ -383,100 +252,13 @@ void Model::_gaussian(pair<size_t, size_t> p)
 		if (row == x) {
 			continue;
 		}
-		if (matrix[row][y] != 0) {
-			double norm = matrix[row][y];
-			for (size_t col = 0; col < matrix[x].size(); col++) {
-				matrix[row][col] = matrix[row][col] - norm * matrix[x][col];
+		if (mt[row][y] != 0) {
+			double norm = mt[row][y];
+			for (size_t col = 0; col < mt[x].size(); col++) {
+				mt[row][col] = mt[row][col] - norm * mt[x][col];
 			}
 		}
 	}
 	basic[x - 1] = y;	// 换元
 }
 
-
-Expr::Expr(double constant)
-	:constant(constant)
-{
-}
-
-Expr::Expr(Var var, double coeff)
-{
-	this->coeffs.resize(var.col + 1);
-	this->coeffs[var.col] = coeff;
-	this->constant = 0;
-}
-
-Expr Expr::operator=(const Expr& rhs)
-{
-	return *this;
-}
-
-void Expr::operator+=(const Expr& expr)
-{
-	coeffs.resize(std::max(coeffs.size(), expr.coeffs.size()));
-	for (int c = 0; c < expr.coeffs.size(); c++) {
-		coeffs[c] += expr.coeffs[c];
-	}
-	constant += expr.constant;
-}
-
-void Expr::operator-=(const Expr& expr)
-{
-	coeffs.resize(std::max(coeffs.size(), expr.coeffs.size()));
-	for (int c = 0; c < expr.coeffs.size(); c++) {
-		coeffs[c] -= expr.coeffs[c];
-	}
-	constant -= expr.constant;
-}
-
-void Expr::operator*=(double mult)
-{
-	for (int c = 0; c < coeffs.size(); c++) {
-		coeffs[c] *= mult;
-	}
-	constant *= mult;
-}
-
-void Expr::operator/=(double a)
-{
-	for (int c = 0; c < coeffs.size(); c++) {
-		coeffs[c] /= a;
-	}
-	constant /= a;
-}
-
-Expr Expr::operator+(const Expr& rhs)
-{
-	coeffs.resize(std::max(coeffs.size(), rhs.coeffs.size()));
-	for (int c = 0; c < rhs.coeffs.size(); c++) {
-		coeffs[c] += rhs.coeffs[c];
-	}
-	constant += rhs.constant;
-	return *this;
-}
-
-Expr Expr::operator-(const Expr& rhs)
-{
-	coeffs.resize(std::max(coeffs.size(), rhs.coeffs.size()));
-	for (int c = 0; c < rhs.coeffs.size(); c++) {
-		coeffs[c] -= rhs.coeffs[c];
-	}
-	constant -= rhs.constant;
-	return *this;
-}
-
-double Var::get(DoubleAttr attr)
-{
-	switch (attr) {
-	case DoubleAttr::Coeff:
-		return coeffs;
-	case DoubleAttr::X:
-		return val;
-	}
-	return val;
-}
-
-int Var::get(IntAttr attr)
-{
-	return col;
-}