Only one input for fis?

[LuQi7755]

SWMM_FLC/FLC_Simulation/MATLAB module/RBC_GAFLC_20190721.m

Line 76 in 4bf7a91

output(n_tsteps,1) = evalfis(fis,input(n_tsteps,1));

I found during simulation, some of flow data would exceed the range of training dataset, that would give a warning in the SWMM progressing part if using trained fis. But here I found it only used 1 input instead of 2 inputs, would you please explain why it behaves this way?