Rounding all input data

[MikkelBosack]

Dear all

Are any of you aware of an easier approach to round all values either directly in GAMS or though Veda? 

The issue is that we occasionally experience scaling issues in some of our models, which most like occurs due to not having rounded values in calculations made in our input data. 

Best Regards
Mikkel

[AKanudia]

I am not sure that rounding has anything to do with scaling issues. You can identify scaling issues with Jacobian analysis though.

[VictorG]

Dear forum members,

I ask the same question again: do you have a method to round your input data to a specific significant figures ?
Not considering properly the decimal figures may lead to numerical issues with the solvers:

Paragraph: Imprecise rounding of matrix coefficient values: https://gurobi-optimization-gurobi-model...lcond.html

Paragraph 3.3.1 : Macmillan, M., Eurek, K., Cole, W., Bazilian, M.D., 2021. Solving a large energy system optimization model using an open-source solver. Energy Strategy Reviews 38, 100755. https://doi.org/10.1016/j.esr.2021.100755

These numbers with a long decimal part can occur frequently with divisions (currency conversion, etc.) I would like to alter the input data of my model without going over all the tables and manually round the data. I have a formula that can be found in the excel file attached, but I do not find any way to use it with veda. Something similar to the scenario Scen_scalingcorrection.xlsx of the advanced demo model would be handy but with rounding instead of truncating. I can also work with gams if you have a suggestion.

Thanks

[Antti-L]

>  I can also work with gams if you have a suggestion.

I could implement such into the TIMES code, for all users, if one can find agreement about the design. 

[VictorG]

Thanks. Doing something similar to RPT_OPT control switch where the user can choose to round attributes like ACT_COST to a specific number of significant figures can be a possibility.