def _transform_m(self, m):
m[0] -= M_BIAS[0]
m[1] -= M_BIAS[1]
m[2] -= M_BIAS[2]
return [dot_product(M_TRANSFORMATION[0], m),
dot_product(M_TRANSFORMATION[1], m),
dot_product(M_TRANSFORMATION[2], m)]
def _calculate_raw_heading(self, a, m, f):
e = normalize_3d(cross_3d(m, a))
n = normalize_3d(cross_3d(a, e))
heading = atan2(dot_product(e, f), dot_product(n, f)) * 180 / pi
return int(round((heading + 360) if heading < 0 else heading))
