Dear All I would like to consult on the following manner: I would like to make it easy to use matrices stored in text files as operators in alps situations. My current solution is:

1. I have found a place where functions such as "sin" are defined in the code. 2. I have added "KroneckerDelta" function 3. I have written a script that produces apriopriate "model.xml" given text files with the operators I want to use in alps.

It seems it works, but the solution is ugly: my custom operator are lengthy sums of the form KD(n,5)*0.321 for the diabonal operators, even worse for general, nondiagonal operator :)

Is there a nicer way to do it ?:) Perhaps it is possible to write a nice function for alps that creates such an operatr.

I would like to ask for a hit for best way to code it :)

Regards, Mateusz Lacki