From 38c0f38d724c13804ea7b9c75c28ba90a3140e07 Mon Sep 17 00:00:00 2001
From: Yi Zhang <zhangyiss@icloud.com>
Date: Tue, 22 Oct 2019 10:52:04 +0800
Subject: [PATCH] Update sample3.cpp

---
 src/sample/sample3.cpp | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/sample/sample3.cpp b/src/sample/sample3.cpp
index dbf97be..9d964c2 100644
--- a/src/sample/sample3.cpp
+++ b/src/sample/sample3.cpp
@@ -39,7 +39,7 @@ TEST_FUNC::TEST_FUNC()
 {
 	m_x = NULL;
 	m_x = lbfgs_malloc(3);
-	m_x[0] = m_x[1] = m_x[2] = 1.0;
+	m_x[0] = m_x[1] = m_x[2] = 0.0;
 }
 
 TEST_FUNC::~TEST_FUNC()
@@ -55,9 +55,9 @@ lbfgsfloatval_t TEST_FUNC::Func(const lbfgsfloatval_t *x, lbfgsfloatval_t *g,
 		const int n, const lbfgsfloatval_t step)
 {
 	double f0,f1,f2,temp;
-	f0 = 3*x[0] + x[1] + 2*x[2]*x[2] - 3;
-	f1 = -3*x[0] + 5*x[1]*x[1] + 2*x[0]*x[2] - 1;
-	f2 = 25*x[0]*x[1] + 20*x[2] + 12;
+	f0 = 3*x[0] + x[1] + 2*x[2]*x[2] - 3.012; //这里添加一点噪声
+	f1 = -3*x[0] + 5*x[1]*x[1] + 2*x[0]*x[2] - 1.0521;
+	f2 = 25*x[0]*x[1] + 20*x[2] + 12.10231;
 	temp = sqrt(f0*f0+f1*f1+f2*f2);
 
 	g[0] = 0.5*(6*f0+2*f1*(2*x[2]-3)+50*f2*x[1])/temp;
@@ -70,19 +70,28 @@ int TEST_FUNC::Progress(const lbfgsfloatval_t *x, const lbfgsfloatval_t *g, cons
 		const lbfgsfloatval_t xnorm, const lbfgsfloatval_t gnorm, const lbfgsfloatval_t step,
 		int n, int k, int ls)
 {
-	clog << "iteration times: " << k << endl;
+	clog << "iteration times: " << k << " fx = " << fx << " gnorm/xnorm = " << gnorm/xnorm << endl;
 	clog << x[0] << " " << x[1] << " " << x[2] << endl;
+
+	if (fx < 1e-10) return 1; //这里我们设置一个方程组的整体目标函数值作为终止条件 因为此方程组在0值处梯度不为0 无法使用梯度条件
 	return 0;
 }
 
 int TEST_FUNC::Routine()
 {
 	lbfgsfloatval_t fx;
-	int ret = lbfgs(3, m_x, &fx, _Func, _Progress, this, NULL);
+
+	lbfgs_parameter_t self_para;
+	lbfgs_parameter_init(&self_para);
+	//self_para.min_step = 1e-30;
+	//self_para.max_linesearch = 40;
+	//self_para.linesearch = LBFGS_LINESEARCH_BACKTRACKING_WOLFE;
+
+	int ret = lbfgs(3, m_x, &fx, _Func, _Progress, this, &self_para);
 
 	clog << "L-BFGS optimization terminated with status: " << endl << lbfgs_strerror(ret) << endl;
 	clog << m_x[0] << " " << m_x[1] << " " << m_x[2] << endl;
-	return 0;
+	return ret;
 }
 
 int main(int argc, char const *argv[])