can deepFM use sparse data format?

[leavingseason]

can deepFM use sparse data format?

[Leavingseason]

hi sddi,
deepFM reads sparse data as input, but notice that each instance must have exactly the same number of features, which is the "field number" in the paper. So if a field is empty or missing, you should append a zero fake value for it.

[sddi]

hi @Leavingseason , thank you for answering. I have millions of features, if i append a zero fake value , the input file maybe very large, could you update the code support the input format likes libsvm format(index:value, if value is zero, omit it in the input file )?

[Leavingseason]

hi sddi,
How many fields of feature (not the number of feature) do you have? Actually we do not request for every feature append a zero value, instead for each field, if there is no feature under it, we will append a zero fake value. The deepFM model use field-wise dense embedding as the input for deep neural network, so the number of fields can not be too large.

[sddi]

oh~~ @Leavingseason i see~~~
for instance, i have two fieds of feature, userID features(index from 0 to 100), itemID features(index from 101 to 1000). for one sample, in the input file maybe, "1 36:1 108:1 123:1 365:1", is it ok?

[Leavingseason]

That's partially right. Now my code only supports at most one feature for each field, which follows the original paper's framework. So for itemID features, you can only keep one itemID. I know you concerns, in the real world, multiple features under one field happens a lot. We have the corresponding version of code to handle this case, which leverages sparse embedding lookup https://www.tensorflow.org/api_docs/python/tf/nn/embedding_lookup_sparse, and the input format becomes fieldID:featureID:value. We will consider to release this version.

[sddi]

OK，thank you very much! I am waiting for your new version~~~:D

[waitingc]

Have the version which supports "multiple features under one field" released ? Thanks

[Leavingseason]

Not yet. All right, since some people are interested in this version, I will release a preview code which is now very ugly. I will try to find some time in two days (it is so sad that KDD deadline is near...)

[Leavingseason]

Done.

[CheungZeeCn]

@Leavingseason hello, 请教一个格式上的问题，fieldID:featureID:value 这里，如果fieldID==1 对应的featureID 有3个，如果fieldID==2对应的featureID 有2个，fieldID==2的 featureID 的值的编码需要基于 fieldID==1 的featureID 上吗？ for example:

0 1:1:1 1:2:1 1:3:1 2:1:1 #这里fieldID==2的 featureID 可以重新编码
0 1:1:1 1:2:1 1:3:1 2:4:1 #这里fieldID==2的 featureID 不可以重新编码,需要基于原来的1之上，谢谢！