I’m a bit surprised to see the following UQLab behaviour. I’ve been setting up a PCE-LARS model with 1 input and specifying LHS as experimental design, e.g.
metamodelLARS.ExpDesign.Sampling = ‘LHS’;
metamodelLARS.ExpDesign.NSamples = 8;
myPCE_LARS = uq_createModel(metamodelLARS);
I look at the samples by studying myPCE_LARS.ExpDesign.X.
The surprise is that when I repeat this, but extending to 2 inputs of which one is a constant, I get different samples (note that the random seed is fixed). I had thought that the constant input would not have to be sampled, but it looks like an LHS of the 2 dimensional space is made, which is then transformed to be constant in the second dimension (somewhere in uq_GeneralIsopTransform). Is that correct? Could you explain me a bit why this is done?