.Solve(-) not working, gives out empty vector

[Icaka00]

Hi, great work on the splines code. I just have a small issue i stumbled upon using it in my project. I'm trying to recreate this splines into my code. Thanks in advance! Here is the issue, the splines and my code:

 int WorldGen(float Cont, float Eros, float PV ) {
			int worldHeight = 0;
			//Peakes & Valleys
			std::vector<double> x1, y1;
			x1.push_back(0.05f);
			y1.push_back(0.f);

			x1.push_back(0.1f);
			y1.push_back(0.1f);

			x1.push_back(0.325f);
			y1.push_back(0.2f);

			x1.push_back(0.5f);
			y1.push_back(0.21f);

			x1.push_back(0.65f);
			y1.push_back(0.55f);

			x1.push_back(0.9f);
			y1.push_back(0.61f);

			x1.push_back(1.f);
			y1.push_back(0.65f);
			tk::spline PVSpl;
			PVSpl.set_points(x1, y1);

			//Erosion
			std::vector<double> x2, y2;
			x2.push_back(0);
			y2.push_back(1);

			x2.push_back(0.15f);
			y2.push_back(0.55f);

			x2.push_back(0.3f);
			y2.push_back(0.41f);

			x2.push_back(0.32f);
			y2.push_back(0.45f);

			x2.push_back(0.45f);
			y2.push_back(PVSpl.solve(PV)[0]);

			x2.push_back(0.6f);
			y2.push_back(0.11f);

			x2.push_back(0.7f);
			y2.push_back(0.11f);

			x2.push_back(0.72f);
			y2.push_back(0.28f);

			x2.push_back(0.78f);
			y2.push_back(0.28f);

			x2.push_back(0.79f);
			y2.push_back(0.11f);

			x2.push_back(0.85f);
			y2.push_back(0.05f);

			x2.push_back(1.f);
			y2.push_back(0.05f);
			tk::spline ErosSpl;
			ErosSpl.set_points(x2, y2);

			//Continetalness
			std::vector<double> x3, y3;
			x3.push_back(0);
			y3.push_back(1);

			x3.push_back(0.09f);
			y3.push_back(0.025f);
			
			x3.push_back(0.345f);
			y3.push_back(0.025f);
			
			x3.push_back(0.385f);
			y3.push_back(0.435f);

			x3.push_back(0.515f);
			y3.push_back(0.435f);

			x3.push_back(0.525f);
			y3.push_back(0.9f);

			x3.push_back(0.55f);
			y3.push_back(0.915f);

			x3.push_back(0.72f);
			y3.push_back(ErosSpl.solve(Eros)[0]);

			x3.push_back(1.f);
			y3.push_back(0.98f);

			tk::spline ContSpl;
			ContSpl.set_points(x3, y3);
			
			worldHeight = ContSpl.solve(Cont)[0] * 100;

			return worldHeight;
		}

[Icaka00]

code update:

int WorldGen(float Cont, float Eros, float PV ) {
			int worldHeight = 0;
			//Peakes & Valleys
			std::vector<double> x1 = { 0.05f, 0.1f, 0.325f, 0.5f,  0.65f, 0.9f,  1.f };
			std::vector<double> y1 = { 0.f,   0.1f, 0.2f,   0.21f, 0.55f, 0.61f, 0.65f };
			tk::spline PVSpl;
			PVSpl.set_points(x1, y1, tk::spline::cspline);
			std::vector<double> PVSol = PVSpl.solve(PV);

			//Erosion
			std::vector<double> x2 = { 0.f, 0.15f, 0.3f,  0.32f, 0.45f,    0.6f,  0.7f,  0.72f, 0.78f, 0.79f, 0.85f, 1.f };
			std::vector<double> y2 = { 1.f, 0.55f, 0.41f, 0.45f, PVSol[0], 0.11f, 0.11f, 0.28f, 0.28f, 0.11f, 0.05f, 0.05f};
			tk::spline ErosSpl;
			ErosSpl.set_points(x2, y2, tk::spline::cspline);
			std::vector<double> ErosSol = ErosSpl.solve(Eros);

			//Continetalness
			std::vector<double> x3 = { 0.f, 0.09f,  0.345f,  0.385f, 0.515f, 0.525f,  0.55f,  0.72f,      1.f};
			std::vector<double> y3 = { 1.f, 0.025f, 0.025f,  0.435f, 0.435f, 0.9f,    0.915f, ErosSol[0], 0.98f};
			tk::spline ContSpl;
			ContSpl.set_points(x3, y3, tk::spline::cspline);
			
			worldHeight = ContSpl.solve(Cont)[0] * 100;

			return worldHeight;
		}