//! Returns true if the current atom is covalently bonded to a given atom.
bool atom::is_neighbor(const atom& a) const
{
assert(this != &a);
const double r = 1.1 * (covalent_radius() + a.covalent_radius());
return distance_sqr(coord, a.coord) < r * r;
}
double distance(struct Point const a, struct Point const b)
{
return sqrt(distance_sqr(a, b));
}
bool atom::has_covalent_bond(const atom& a) const
{
const float s = covalent_radius() + a.covalent_radius();
return distance_sqr(coord, a.coord) < s * s;
}
int insect(Circle c1,Circle c2)
{
double d,a,b,c,p,q,r;
double cos_value[2], sin_value[2];
if (double_equals(c1.p.x, c2.p.x)&& double_equals(c1.p.y,c2.p.y)&& double_equals(c1.r, c2.r))
{
return 0;
}
d = distance(c1.p, c2.p);
if (d > c1.r + c2.r||d < fabs(c1.r - c2.r))
{
return 0;
}
a = 2.0 * c1.r * (c1.p.x - c2.p.x);
b = 2.0 * c1.r * (c1.p.y - c2.p.y);
c = c2.r * c2.r - c1.r * c1.r- distance_sqr(c1.p,c2.p);
p = a * a + b * b;
q = -2.0 * a * c;
if(p==0)return 0;
if (double_equals(d,c1.r +c2.r)|| double_equals(d, fabs(c1.r - c2.r)))
{
cos_value[0] = -q / p / 2.0;
sin_value[0] = sqrt(1 - cos_value[0] * cos_value[0]);
I0->x = c1.r * cos_value[0] + c1.p.x;
I0->y = c1.r * sin_value[0] + c1.p.y;
if (!double_equals(distance_sqr(*I0, c2.p),c2.r * c2.r))
{
I0->y = c1.p.y - c1.r * sin_value[0];
}
return 1;
}
r = c * c - b * b;
cos_value[0] = (sqrt(q * q - 4.0 * p * r) - q) / p / 2.0;
cos_value[1] = (-sqrt(q * q - 4.0 * p * r) - q) / p / 2.0;
sin_value[0] = sqrt(1 - cos_value[0] * cos_value[0]);
sin_value[1] = sqrt(1 - cos_value[1] * cos_value[1]);
I0->x = c1.r * cos_value[0] + c1.p.x;
I1->x = c1.r * cos_value[1] + c1.p.x;
I0->y = c1.r * sin_value[0] + c1.p.y;
I1->y = c1.r * sin_value[1] + c1.p.y;
if (!double_equals(distance_sqr(*I0, c2.p),c2.r * c2.r))
{
I0->y = c1.p.y - c1.r * sin_value[0];
}
if (!double_equals(distance_sqr(*I1, c2.p),c2.r * c2.r))
{
I1->y = c1.p.y - c1.r * sin_value[1];
}
if (double_equals(I0->y, I1->y)&& double_equals(I0->x, I1->x))
{//改到这里了
if (I0->y > 0)
{
I1->y = -I1->y;
} else
{
I0->y = -I0->y;
}
}
return 2;
}
float point_line_distance_sqr(float4 point, line4 line)
{
return distance_sqr(point, line.a + line.b * param_nearest_on_line(point, line));
}