# Indexing of NDEigensystem Result on a Cluster

I am trying to run on a cluster (where the version 11 of Mathematica is available) a code involving the following calculation:

    1). {Values, States} = NDEigensystem[{-D[u[r], {r, 2}] + V[r] u[r], u[R] == 0}, u[r], {r,0,R}, 10];


where I omitted the method specifications.

When I run it on my laptop (where I use the version 12.2), I have no problem accessing the different eigenstates with Evaluate[States][[i]] or, equivalently, with Evaluate[States[[i]]], but on the cluster I get an error saying that the left and righthand side of equation 1) have a different shape.

I then tried to name the lefthand side of 1) simply as Solution and to access the eigenvalues with Evaluate[Solution][[1,i]] and Evaluate[Solution][[2,i]] (or Evaluate[Solution[[1,i]]] and Evaluate[Solution[[2,i]]]) respectively. Again, both work on my laptop but neither of them work on the cluster. In this case, the error says that part 2 (or more) of u[r] does not exist.

Moreover, even the calculation of the first eigenstate seems to be different.

Is there something I am not considering about the difference between the two versions of Mathematica? Or is there any difference between running a code locally or on a cluster?

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• I do not believe that versions 11 vs 12 would matter here. Aug 11, 2021 at 16:51