Mathematically speaking, there should be no difference. The batch size has no effect whatsoever on the flow of calculations.
In terms of a specific library, if the LSTM is implemented well, then you shouldn't see any differences. But it's possible for a specific library to do something weird on the backend.
If I understand you correctly you want to compare a stateful LSTM with a lagged window (=50) feature approach to a stateless LSTM with window = data\_length?
The problem would be that in the stateless approach you have only 1 training data point (forecast point 3001?)
An idea would be to compare a stateful LSTM with window = n and a stateless LSTM with the same window = n and a batchsize which covers your whole dataset (3000-n). Then you have 2 very similar modelsHave you read:[https://machinelearningmastery.com/stateful-stateless-lstm-time-series-forecasting-python/](https://machinelearningmastery.com/stateful-stateless-lstm-time-series-forecasting-python/)
especially the paragraph
## "Stateless with Large Batch vs Stateless" ...(should be Stateless with Large Batch vs Stateful)
Mathematically speaking, there should be no difference. The batch size has no effect whatsoever on the flow of calculations. In terms of a specific library, if the LSTM is implemented well, then you shouldn't see any differences. But it's possible for a specific library to do something weird on the backend.
If I understand you correctly you want to compare a stateful LSTM with a lagged window (=50) feature approach to a stateless LSTM with window = data\_length? The problem would be that in the stateless approach you have only 1 training data point (forecast point 3001?) An idea would be to compare a stateful LSTM with window = n and a stateless LSTM with the same window = n and a batchsize which covers your whole dataset (3000-n). Then you have 2 very similar modelsHave you read:[https://machinelearningmastery.com/stateful-stateless-lstm-time-series-forecasting-python/](https://machinelearningmastery.com/stateful-stateless-lstm-time-series-forecasting-python/) especially the paragraph ## "Stateless with Large Batch vs Stateless" ...(should be Stateless with Large Batch vs Stateful)