# Developer Documentation

## Variable, Constraint, and Parameter Naming

### Suffixes

`_des`

: used to denote a concept specific to network design problems`_on_off`

: used to denote a concept where there are either-or choices, such as pump operations

### Total Hydraulic Head

`h`

: total hydraulic head`dh`

: difference in head between nodes`dhp`

: (nonnegative) difference in head between tail and head nodes`dhn`

: (nonnegative) difference in head between head and tail nodes

### Volumetric Flow Rate

`q`

: volumetric flow rate ("flow"), which can be negative or nonnegative`qp`

: positively-directed flow magnitude (i.e., flow transported from`node_fr`

to`node_to`

)`qn`

: negatively-directed flow magnitude (i.e., flow transported from`node_to`

to`node_fr`

)