Cython - M1RI

struct vec3{
    long s;     # What are s and u for?
    long u;
};

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cdef vec3 * matrix_to_m1ri(M):
    cdef vec3 t
    cdef vec3 *R = <vec3 *>sage_malloc(M1RI_BITS * sizeof(vec3))
    cdef long ptr, i

    i = 0
    for row in M:
    t.u = 0
    t.s = 0
    ptr = 1
    j = 0
    for x in row:
        if x != 0:
        t.u |= ptr
        if x == 2:      # Why check x!=0 and x==2? I think this will make sense if I know
            t.s |= ptr  # what long s and long u are.
        ptr += ptr
    R[i] = t
    i+=1
    return R

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cdef vec3 * print_m1ri(vec3 *M):
    cdef long i, j, ptr
    global D
    for i from 0 <= i < M1RI_BITS:
    ptr = 1
    s = ''
    for j from 0 <= j < M1RI_BITS:
        if M[i].u&ptr:
        if M[i].s&ptr:
            s += ':'                # We printing the matrix using only
        else:                   # : . ? and the space characters?
            s += '.'                # What sort of output is this?
        elif M[i].s & ptr:
        s += '?'
        else:
        s += ' '
        ptr += ptr
    print s