avoid division by zero in MathExtra normalize functions (86153a0f) · Commits · 郑智淋 / lammps

src/math_extra.h

+21 −12

Original line number	Diff line number	Diff line
		@@ -169,11 +169,14 @@ inline void MathExtra::zero3(double *v)

		inline void MathExtra::norm3(double *v)
		{
		double scale = 1.0/sqrt(v[0]v[0]+v[1]v[1]+v[2]*v[2]);
		const double val = v[0]v[0]+v[1]v[1]+v[2]*v[2];
		if (val > 0.0) {
		const double scale = 1.0/sqrt(val);
		v[0] *= scale;
		v[1] *= scale;
		v[2] *= scale;
		}
		}

		/* ----------------------------------------------------------------------
		normalize a vector, return in ans
		@@ -181,11 +184,14 @@ inline void MathExtra::norm3(double *v)

		inline void MathExtra::normalize3(const double v, double ans)
		{
		double scale = 1.0/sqrt(v[0]v[0]+v[1]v[1]+v[2]*v[2]);
		const double val = v[0]v[0]+v[1]v[1]+v[2]*v[2];
		if (val > 0.0) {
		double scale = 1.0/sqrt(val);
		ans[0] = v[0]*scale;
		ans[1] = v[1]*scale;
		ans[2] = v[2]*scale;
		}
		}

		/* ----------------------------------------------------------------------
		scale a vector to length
		@@ -194,11 +200,14 @@ inline void MathExtra::normalize3(const double v, double ans)
		inline void MathExtra::snormalize3(const double length, const double *v,
		double *ans)
		{
		double scale = length/sqrt(v[0]v[0]+v[1]v[1]+v[2]*v[2]);
		const double val = v[0]v[0]+v[1]v[1]+v[2]*v[2];
		if (val > 0.0) {
		double scale = length/sqrt(val);
		ans[0] = v[0]*scale;
		ans[1] = v[1]*scale;
		ans[2] = v[2]*scale;
		}
		}

		/* ----------------------------------------------------------------------
		negate vector v