def update(self, doc, process=None):
        if process is None:
            pk = 'id'
            id = doc.id
            doc.synced = False
            set = doc
        elif process == UPDATE_PROCESS:
            if self.db.docs.find({'sid': doc.sid}).count() == 0:
                return self.insert(doc, synced=True)
            pk = 'sid'
            id = doc.sid
            doc.synced = not doc.merged() # must be commited if was merged
            doc.merged(False)
            set = {'tid': doc.tid, 'data': doc.data, 'user': doc.user,
                   'public': doc.public, 'synced': doc.synced}
        elif process == COMMIT_PROCESS:
            pk = 'id'
            id = doc.id
            doc.synced = True
            set = {'sid': doc.sid, 'tid': doc.tid, 'synced': doc.synced}
        else:
            raise DatabaseException('Incorrect update process')

        try:
            rs = self.db.docs.update({pk: id}, {'$set': set}, safe=True)
            assert rs['n'] == 1
        except Exception as e:
            raise DatabaseException(e)
        return doc
def forcedens_fft(title, fdens, ax=0):
    """plot force densities FFT
    Args:
      title: plot title
      fdens: force density object
    """
    if ax == 0:
        ax = plt.axes(projection="3d")

    F = 1e-3*fdens.fft()
    fmin = 0.2
    num_bars = F.shape[0] + 1
    _xx, _yy = np.meshgrid(np.arange(1, num_bars),
                           np.arange(1, num_bars))
    z_size = F[F > fmin]
    x_pos, y_pos = _xx[F > fmin], _yy[F > fmin]
    z_pos = np.zeros_like(z_size)
    x_size = 2
    y_size = 2

    ax.bar3d(x_pos, y_pos, z_pos, x_size, y_size, z_size)
    ax.view_init(azim=120)
    ax.set_xlim(0, num_bars+1)
    ax.set_ylim(0, num_bars+1)
    ax.set_title(title)
    ax.set_xlabel('M')
    ax.set_ylabel('N')
    ax.set_zlabel('kN/m²')