Constant ERR_COEFF_3 

pub const ERR_COEFF_3: f64 = _; // 1.7763568394002536E-15f64

Absolute error coefficient for Matrix::<3>::det_direct.

This constant is not a caller-tuned tolerance. It is the dimension-specific multiplier that turns the matrix’s absolute Leibniz sum into a conservative bound on floating-point roundoff in the closed-form 3×3 determinant formula.

For any 3×3 matrix A with finite f64 entries,

|A.det_direct() - det_exact(A)|  ≤  ERR_COEFF_3 · p(|A|)

where p(|A|) is the absolute Leibniz sum (the same cofactor expansion as det_direct but with |·| at every leaf). det_direct for D=3 uses three 2×2 FMA minors combined by a nested FMA, yielding the 8·EPS + 64·EPS² bound. See REFERENCES.md [8] for the Shewchuk framework these bounds follow.

Prefer Matrix::det_errbound over this constant for typical use; see ERR_COEFF_2 for a worked example.