Hi, I think I found a bug in gretl that is quite subtle. The attached script demonstrates the bug -- or actually in its current form it demonstrates how to work around the bug. If you run it like this, it will produce the desired output; especially important is the fact that in the three iterations the printed "variant1" matrix changes. In order to trigger the bug, comment out the lines with the corresponding remark and uncomment the ones with the other remark (self-explanatory I hope). The symptom is that now the different "variant1" matrices are identical. Unfortunately the script still is quite complex for a minimal script. The only difference between the commented-out and active lines AFAICS is whether some matrices are directly created and manipulated as bundle members, or I work with temp matrices that only in the end (of the function) are assigned to new bundle member items. In this script a fair amount of bundles are created, passed around between functions, and also manipulated in loops within functions. This somehow seems to confuse gretl. thanks, Sven