Book05 recommendation systems: CPU version loss convergence comparison.

[peterzhang2029]

Train avg_cost:

Pass	V2(CPU)	Fluid(CPU)
0	4.226960	4.16706371
1	3.779475	3.80107117
2	3.467975	3.51753116
3	3.296452	3.30209279
4	3.226693	3.19562387

Test avg_cost:

Pass	V2(CPU)	Fluid(CPU)
0	3.830754	3.843338
1	3.587173	3.665708
2	3.371037	3.390050
3	3.323361	3.319620
3	3.299071	3.293895

[shanyi15]

您好，此issue在近一个月内暂无更新，我们将于今天内关闭。若在关闭后您仍需跟进提问，可重新开启此问题，我们将在24小时内回复您。因关闭带来的不便我们深表歉意，请您谅解~感谢您对PaddlePaddle的支持!
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