# No output arrays were provided

**URL:** <https://community.konduit.ai/t/no-output-arrays-were-provided/2710>\
**Category:** ND4J\
**Created:** [July 30, 2023, 9:07pm UTC](https://community.konduit.ai/t/no-output-arrays-were-provided/2710 "2023-07-30T21:07:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![adonnini](https://avatars.discourse-cdn.com/v4/letter/a/5f8ce5/32.png) [@adonnini](https://community.konduit.ai/u/adonnini)\
**Post date:** [July 30, 2023, 9:07pm UTC](https://community.konduit.ai/t/no-output-arrays-were-provided/2710/1 "2023-07-30T21:07:44Z")

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Hi,

I cannot think of a reason why the following line:

```java
        INDArray concatenatedData = Nd4j.concat(1,
                trainData.next().getFeatures().get(all(), all(), interval(0, trainData.next().getFeatures().size(1)), interval(1, trainData.next().getFeatures().size(2))),
                trainData.next().getFeatures().get(all(), all(), all(), interval(1, trainData.next().getFeatures().size(2)))
        );

```

causes the following error:  
`Op name concat - no output arrays were provided and calculateOutputShape failed to execute`

Is it because the `INDArray` `concatenatedData` was not initialized?

Thanks

---

<div class="post-metadata">

**Author:** ![agibsonccc](https://yyz1.discourse-cdn.com/flex035/user_avatar/community.konduit.ai/agibsonccc/32/697_2.png) [@agibsonccc](https://community.konduit.ai/u/agibsonccc)\
**Post date:** [July 30, 2023, 10:32pm UTC](https://community.konduit.ai/t/no-output-arrays-were-provided/2710/2 "2023-07-30T22:32:16Z")

</div>

@adonnini check if the features were null somewhere. There’s no “init” anywhere there. The array either exists or it doesn’t.