# Crate robust_geo[−][src]

Implementation of the floating point expansions found in Adaptive Precision Floating-Point Arithmetic and Fast Robust Geometric Predicates by Shewchuk in a more Rusty style. Double precision only.

## Functions

 cross_2d Computes the determinant of the following matrix in_circle Returns a positive number if `d` is inside the oriented circle that goes through `a`, `b`, `c`, a negative number if it lies outside, and 0 if `a`, `b`, `c`, `d` are cocircular or `a`, `b`, `c` are collinear. If `a`, `b`, `c` are in counterclockwise order, "inside the circle" is the inside. If `a`, `b`, `c` are in clockwise order, "inside the circle" is the outside. in_sphere Returns a positive number if `e` is inside the oriented sphere that goes through `a`, `b`, `c`, `d`, a negative number if it lies outside, and 0 if `a`, `b`, `c`, `d`, `e` are cospherical or `a`, `b`, `c`, `d` are coplanar. If `a`, `b`, `c`, `d` are oriented positive, "inside the sphere" is the inside. If `a`, `b`, `c`, `d` are oriented negative, "inside the sphere" is the outside. magnitude_cmp_2d Compares the magnitude of `a` and `b` and returns a positive number if `a`'s magnitude is greater, a negative number if `b`'s magnitude is greater, and 0 if their magnitudes equal. magnitude_cmp_3d Compares the magnitude of `a` and `b` and returns a positive number if `a`'s magnitude is greater, a negative number if `b`'s magnitude is greater, and 0 if their magnitudes equal. orient_2d Calculates the orientation of points `a`, `b`, `c` in a plane. Returns twice the area of the triangle formed by `a`, `b`, and `c`, which is a positive number if they define a left turn, a negative number if they define a right turn, and 0 if they are collinear. orient_3d Calculates the orientation of points `a`, `b`, `c`, `d` in a space. Returns 6 times the volume of the tetrahedron formed by `a`, `b`, `c`, `d`, which is a positive number if `b`→`c`→`d` defines a left turn when looked at from `a`, a negative number if they define a right turn, and 0 if `a`, `b`, `c`, `d` are coplanar. sign_det_x2y2_plus_2x_det_x Computes the following sum of determinants. sign_det_x2y2z2_plus_2x_det_x Computes the following sum of determinants. sign_det_x_x2y2 Computes the determinant of the following matrix sign_det_x_x2y2_plus_2x_det_x_y Computes the following sum of determinants. sign_det_x_x2y2z2 Computes the determinant of the following matrix sign_det_x_x2y2z2_plus_2x_det_x_y Computes the following sum of determinants. sign_det_x_y_x2y2z2 Computes the determinant of the following matrix sign_det_x_y_x2y2z2_plus_2x_det_x_y_z Computes the following sum of determinants