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tests: added `get_angle` test function in geometry/vector3d (#838) 

* feat: add get_angle algorithm

* docs: added documentation for get_angle algorithm

* test: add test for get_angle algorithm

* fix: Fixed indentation

* Test: Changed //printf to // printf

* fix: Changed variable description for norm_a and norm_b

* fix: changed // to /// in the comment as suggested

* Apply suggestions from code review

* Apply suggestions from code review

* Apply suggestions from code review

* Apply suggestions from code review

Co-authored-by: David Leal <halfpacho@gmail.com>
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lasgel 2021-07-09 20:52:29 +02:00 committed by GitHub
parent 08157c4129
commit 31ced8233e
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27
geometry/vectors_3d.c
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@ -191,6 +191,29 @@ mat_3x3 get_cross_matrix(const vec_3d *a)
return A;
}
/**
* Obtain the angle between two given vectors.
* @f[\alpha=acos\left(\frac{\vec{a} \cdot \vec{b}}{\lVert\vec{a}\rVert \cdot \lVert\vec{b}\rVert}\right)@f]
* @param[in] a first input vector
* @param[in] b second input vector
* @returns angle between @f$\vec{a}@f$ and @f$\vec{b}@f$ in radians
*/
double get_angle(const vec_3d *a, const vec_3d *b)
{
double alpha, cos_alpha;
float norm_a = vector_norm(a); ///< The norm of vector a
float norm_b = vector_norm(b); ///< The norm of vector b
if (fabsf(norm_a) < EPSILON || fabsf(norm_b) < EPSILON) /// detect possible division by 0 - the angle is not defined in this case
{
return NAN;
}
cos_alpha = dot_prod(a, b) / (norm_a * norm_b);
alpha = acos(cos_alpha); // delivers the radian
return alpha; // in range from -1 to 1
}
/** @} */
/**
@ -223,6 +246,10 @@ static void test()
assert(fabsf(c.x - (-1.f)) < 0.01);
assert(fabsf(c.y - (2.f)) < 0.01);
assert(fabsf(c.z - (-1.f)) < 0.01);
double alpha = get_angle(&a, &b);
// printf("The angle is %f\n", alpha);
assert(fabsf(alpha - 0.387597) < 0.01);
}
/**