1#cython: cdivision=True
2#cython: nonecheck=False
3#cython: wraparound=False
4import numpy as np
5cimport numpy as cnp
6
7from .._shared.fused_numerics cimport np_floats
8cnp.import_array()
9
10
11def moments_hu(np_floats[:, :] nu):
12    if np_floats is cnp.float32_t:
13        dtype = np.float32
14    else:
15        dtype = np.float64
16
17    cdef np_floats[::1] hu = np.zeros((7, ), dtype=dtype)
18    cdef np_floats t0 = nu[3, 0] + nu[1, 2]
19    cdef np_floats t1 = nu[2, 1] + nu[0, 3]
20    cdef np_floats q0 = t0 * t0
21    cdef np_floats q1 = t1 * t1
22    cdef np_floats n4 = 4 * nu[1, 1]
23    cdef np_floats s = nu[2, 0] + nu[0, 2]
24    cdef np_floats d = nu[2, 0] - nu[0, 2]
25    hu[0] = s
26    hu[1] = d * d + n4 * nu[1, 1]
27    hu[3] = q0 + q1
28    hu[5] = d * (q0 - q1) + n4 * t0 * t1
29    t0 *= q0 - 3 * q1
30    t1 *= 3 * q0 - q1
31    q0 = nu[3, 0]- 3 * nu[1, 2]
32    q1 = 3 * nu[2, 1] - nu[0, 3]
33    hu[2] = q0 * q0 + q1 * q1
34    hu[4] = q0 * t0 + q1 * t1
35    hu[6] = q1 * t0 - q0 * t1
36    return np.asarray(hu)
37