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geometry: standardize is_in() semantics and optimize H-Polytope boundary checks #451

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geometry: standardize is_in() semantics and optimize H-Polytope boundary checks #451

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9 changes: 4 additions & 5 deletions include/convex_bodies/ball.h
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Original file line number Diff line number Diff line change
Expand Up @@ -54,11 +54,10 @@ class Ball{
return c.dimension();
}

int is_in(Point const& p) const
{
if (p.squared_length() <= R)
return -1;
else return 0;
int is_in(Point const& p, NT tol = NT(0)) const {
NT diff = (p - c).squared_length() - R;
if (diff > tol) return 1;
return (diff >= -tol) ? 0 : -1;
}

std::pair<NT,NT> line_intersect(Point const& r, Point const& v) const
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11 changes: 7 additions & 4 deletions include/convex_bodies/convex_body.h
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Expand Up @@ -97,11 +97,14 @@ class ConvexBody {
}

// Check if point is in K
int is_in(Point const& p, NT tol=NT(0)) {
for (func g : gs) {
if (g(p) > NT(-tol)) return 0;
int is_in(Point const& p, NT tol=NT(0)) const {
NT max_val = -std::numeric_limits<NT>::max();
for (const auto& g : gs) {
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@Mohit-Lakra Mohit-Lakra Feb 21, 2026

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Nice - adding const and using const auto& are good improvements.

NT val = g(p);
if (val > tol) return 1;
if (val > max_val) max_val = val;
}
return -1;
return (max_val >= -tol) ? 0 : -1;
}

};
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18 changes: 5 additions & 13 deletions include/convex_bodies/hpolytope.h
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Original file line number Diff line number Diff line change
Expand Up @@ -324,19 +324,11 @@ class HPolytope {


//Check if Point p is in H-polytope P:= Ax<=b
int is_in(Point const& p, NT tol=NT(0)) const
{
int m = A.rows();
const NT* b_data = b.data();

for (int i = 0; i < m; i++) {
//Check if corresponding hyperplane is violated
if (*b_data - A.row(i) * p.getCoefficients() < NT(-tol))
return 0;

b_data++;
}
return -1;
int is_in(Point const& p, NT tol=NT(0)) const {
Eigen::Matrix<NT, Eigen::Dynamic, 1> res = A * p.getCoefficients() - b;
NT max_val = res.maxCoeff();
if (max_val > tol) return 1;
return (max_val >= -tol) ? 0 : -1;
Comment on lines +327 to +331
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@Mohit-Lakra Mohit-Lakra Feb 21, 2026

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This breaks ComputeInnerBall()
if (is_in(Point(...)) == 0 || ...)

Old: == 0 meant outside (correct)
New: == 0 means boundary (wrong - accepts invalid inner balls)

Also,
The old loop had early exit on first violation. This always computes full A*p and allocates temp vector.

}

// compute intersection point of ray starting from r and pointing to v
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