Hi @sebacastroh ,

I assume those two days were spent in computing the full computational model on the 3'000 points so indeed it makes sense to reuse them.

Suppose you have the LHS design of 3'000 sample points stored in the variable `X`

and an INPUT object used to create the sample stored in variable `myINPUT`

. You can add additional LHS points to the using the function `uq_enrichLHS`

as follows:

```
Xn = uq_enrichLHS(X, Nn, myInput)
```

where `Nn`

is the number of additional points you want to add to the design. The function will return only those new points. You can then use these new points to compute the full computational model (using `uq_evalModel`

to get `Yn`

). After concatenating the new points (both `Xn`

and `Yn`

) to the original design, you can then use them recompute the PCE model (i.e., using existing data).

`uq_enrichLHS`

basically tries to find new points in a given LHS design such that the newly enriched design will also be an LHS. This is not always possible and the resulting design would most probably be a pseudo LHS. Suppose you want to enrich your already enriched LHS design again, you might encounter the following error:

```
X = [X; Xn]; % concatenate the enrichment points to get the enriched design
Xn = uq_enrichLHS(X, 2, myInput)
Error using uq_enrichLHS (line 88)
The initial sample set does not form a Latin Hypercube! For eniriching such set in a pseudo-LHS fashion use uq_LHSify function instead.
```

In this case, as suggested by the error message, the function `uq_LHSify`

can be used in place of `uq_enrichLHS`

.

I hope this helps!