loop for pair-wise column calculation

KNIME Analytics Platform
1

I am trying to set up a loop to do a pair-wise column calculation. In each iteration, a value will be caculated for two columns. A N column input table should yeild N*N values. Any idear for the best approach?

- jian

2

Hi Jian,

I would use two column list loop start and than join those two columns together. Finally use two loop ends to collect your results in the end. A good approach is to append the column names.Than you can afterwards use the pivoting node for creating a matrix (which than can be visualized with the heat map)

I hope this helps :-)

Iris

3

Hi Iris,

That was exactly I did  and encountered a problem: the join node doesn't like to take two loop starts as inputs. I guess the two loops can not be indepedent to each other. 

WARN  Column List Loop Start 0:130      Unable to merge flow object stacks: Conflicting FlowObjects: <Loop Context (Head 0:130, Tail 0:135)> - iteration 12 vs. <Loop Context (Head 0:131, Tail unassigned)> - iteration 0 (loops/scopes not properly nested?)

- jian

4

Yes, sometime the tree is not clear, than you can help with flow variable connection as in the attached image.

Cheers, Iris

 

 

5

yes, that works very well. Thank you very much!

- jian