How can I prevent AMPL from transforming my problem?

To suppress the presolve phase, set option presolve 0 .

To suppress transformation of piecewise-linear terms, set option pl_linearize 0 .

To suppress elimination of variables by substitution from constraints, set option substout 0 . (This is the default setting.) Substitutions specified within var declarations are always applied.

To see a summary of transformations performed, set option show_stats 1 .