Поскольку вы используете numpy, используйте np.repeat
+ np.reshape
:
>>> np.repeat(arr, 3).reshape(-1, 3)
array([[9.975, 9.975, 9.975],
[9.976, 9.976, 9.976],
[9.977, 9.977, 9.977],
[9.978, 9.978, 9.978],
[9.979, 9.979, 9.979],
[9.98 , 9.98 , 9.98 ],
[9.981, 9.981, 9.981],
[9.982, 9.982, 9.982],
[9.983, 9.983, 9.983],
[9.984, 9.984, 9.984],
[9.985, 9.985, 9.985],
[9.986, 9.986, 9.986],
[9.987, 9.987, 9.987],
[9.988, 9.988, 9.988],
[9.989, 9.989, 9.989],
[9.99 , 9.99 , 9.99 ],
[9.991, 9.991, 9.991],
[9.992, 9.992, 9.992],
[9.993, 9.993, 9.993],
[9.994, 9.994, 9.994]])