Hi,
the for loops are setting the input values for your engine. Initially, the first loop sets the first input variable to different values from WT.minimum to WT.maximum incrementing by WT.range/20. The second loop sets the second variable to different values from TQ.minimum to TQ.maximum incrementing by TQ.range/20. So you have:
WT = minimum+0*range/20; TQ = minimum+0*range/20; PD=output
WT = minimum+0*range/20; TQ = minimum+1*range/20; PD=output
WT = minimum+0*range/20; TQ = minimum+2*range/20; PD=output
…
WT = minimum+1*range/20; TQ = minimum+0*range/20; PD=output
WT = minimum+1*range/20; TQ = minimum+1*range/20; PD=output
WT = minimum+1*range/20; TQ = minimum+2*range/20; PD=output
and so on. It sets the inputs of the variables to different combinations so you know the outputs.
The logger just shows information in console, much like System.out.println.