Multiple Sequence Input for LSTM (error message)

Hi all,

I'm new in Matlab and facing an issue.

I wanna try to use multiple sequences inputs for LSTM as below:

and it will be connected to get a new output prediction. each sequence projects each time value as t=0, t=1 and t=2. three of them will be proceeded to the LSTM layer separatedly instead of using the same layer. the error message saying that I only can put one sequence input. So I have been wondering, should the architecture be like this?

the inputs are t=0, t=1 and t=2. the output will be t=3. the next looping input will be t=1, t=2 and t=3 to get the t=4 output and so on and so on. The layer may be changed to GRU in this case but generally, the input model should be like the first picture.

Logically, the sequence input on the second model will be proceeded 3 times in each LSTM instead of the data separatedly proceeded in 3 set of time in 3 uncorrelated LSTM layers.

Kindly help me on this matter.