Nested Loop Problem - Parameter Opt Loop for ARIMA within Group Loop

I’m attempting to optimize the parameters of an ARIMA model over a several grouped time series and I’m running into a nested loop problem. In the data set, there are two products with a time listed as a single column. I first use the Group Loop Start and point to the “product” column as the group. Then I pass those rows to a Parameter Optimization Loop which contains a ARIMA learner, predictor and scorer node. I’ve been able to get both loops to run independently with no problems (unnested to make sure I’ve got the individual pieces correct), but when I put them together I get the following:

  • Unable to merge flow object stacks: Conflicting FlowObjects: <Loop Context (Head 0:7, Tail unassigned)> - iteration 0 vs. <Loop Context (Head 0:20, Tail unassigned)> - iteration 0 (loops/scopes not properly nested?)

I assuming that somewhere I’m not specifying iterations correctly or perhaps I’ve run into an ARIMA node problem?

HI drbheazy,

Just connect the flow variable output of the Group Loop Start node with the flow variable input of the Parameter Optimization Loop Start node: