Dear @Pilgrim
I am trying to use the PCE method to predict the ignition delay time based on a temperature input.
To me it looks like you’re confusing inverse and forward uncertainty quantification.
You gave analytical expression for this here: PCE - Why is coefficient of variance and standard deviation so high?. If I understand your goal correctly, then there is no need to construct a PCE. Please have a look at inverse UQ and reconsider if what you’re trying to do/you’re describing makes sense. You may find this UQLab manual helpful:
Best regards
Styfen