# Can't merge MultiDataSets containing 1-dimensional inputs?

**URL:** <https://community.konduit.ai/t/cant-merge-multidatasets-containing-1-dimensional-inputs/924>\
**Category:** ND4J\
**Created:** [October 12, 2020, 6:53pm UTC](https://community.konduit.ai/t/cant-merge-multidatasets-containing-1-dimensional-inputs/924 "2020-10-12T18:53:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Xom](https://yyz1.discourse-cdn.com/flex035/user_avatar/community.konduit.ai/xom/32/336_2.png) [@Xom](https://community.konduit.ai/u/Xom)\
**Post date:** [October 12, 2020, 6:53pm UTC](https://community.konduit.ai/t/cant-merge-multidatasets-containing-1-dimensional-inputs/924/1 "2020-10-12T18:53:02Z")

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I have a List on which I’m trying to call MultiDataSet.merge. Each MDS in the list contains one example with 2 feature arrays and 3 label arrays; the feature arrays are respectively 3-dimensional (9x9x19) and 1-dimensional (11 “global” variables); the label arrays are 3-d, scalar, and scalar.

I get an exception at org.nd4j.linalg.dataset.api.DataSetUtil.mergeFeatures(DataSetUtil.java:211), which expects arrays of 2 to 4 dimensions only.

Why not 1-dimensional arrays? Am I missing a concept?

(So far I’ve just been preparing my data, and I haven’t started specifying my ComputationGraph yet.)

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<div class="post-metadata">

**Author:** ![Xom](https://yyz1.discourse-cdn.com/flex035/user_avatar/community.konduit.ai/xom/32/336_2.png) [@Xom](https://community.konduit.ai/u/Xom)\
**Post date:** [October 13, 2020, 3:40am UTC](https://community.konduit.ai/t/cant-merge-multidatasets-containing-1-dimensional-inputs/924/2 "2020-10-13T03:40:35Z")

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It turns out that the first dimension is across examples, so if each example has a 1-dimensional input, the total number of dimensions should be 2.