def mirror_arm_joints(x):
    return np.r_[-x[0],x[1],-x[2],x[3],-x[4],x[5],-x[6]]
Returns the index of the primary key field in the self.concrete_fields
dataset/ETHPy150Open rll/lfd/lfd/environment/sim_util.py/mirror_arm_joints--crossover with--dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/Django-1.6.10/django/db/models/options.py/Options.pk_index