gtopt/constraint_expr.hpp file

Supported element types and attributes

Variable scaling

Some LP variables are internally scaled for numerical conditioning. User constraints are written in physical units; the resolver automatically applies the correct scale factor to each coefficient so that the LP constraint is dimensionally correct.

The resolver uses LinearProblem::get_col_scale() to read the scale factor that was stored at variable-creation time, so all current and future scaled variables are handled uniformly.

Stage-level vs block-level attributes

Most attributes are block-level variables (one value per block per stage). Some are stage-level (one value per stage), returned for every block:

Stage-level attributes may appear in any per-block constraint expression; the same LP column is referenced across all blocks in the stage.

Grammar (pseudo-BNF)

constraint   := expr comp_op expr [',' for_clause]
             |  number comp_op expr comp_op number [',' for_clause]

expr         := term (('+' | '-') term)*

term         := [number '*'] element_ref
             |  [number '*'] sum_expr
             |  ['-'] number

element_ref  := element_type '(' string ')' '.' attribute

sum_expr     := 'sum' '(' element_type '(' string_list ')' '.'
                attribute ')'
             |  'sum' '(' element_type '(' 'all' [ ',' 'type' '=' string ]
')'
                '.' attribute ')'

string_list  := string (',' string)*

element_type := 'generator' | 'demand' | 'line' | 'battery'
             |  'converter' | 'reservoir' | 'bus'
             |  'waterway'  | 'turbine'
             |  'junction'  | 'flow' | 'seepage'
             |  'flow_right' | 'volume_right'
             |  'reserve_provision' | 'reserve_zone'

attribute    := IDENT

comp_op      := '<=' | '>=' | '='

for_clause   := 'for' '(' index_spec (',' index_spec)* ')'

index_spec   := index_dim ('in' | '=') index_set

index_dim    := 'scenario' | 'stage' | 'block'

index_set    := 'all'
             |  '{' index_values '}'
             |  number '..' number
             |  number

index_values := index_value (',' index_value)*

index_value  := number
             |  number '..' number

comment      := '#' <any>* EOL
             |  '//' <any>* EOL

Namespaces

namespace gtopt

Classes

struct gtopt::ConstraintDomain

Domain over which a constraint is instantiated.

struct gtopt::ConstraintExpr

Complete parsed constraint expression.

struct gtopt::ConstraintTerm

A single term in a constraint expression.

struct gtopt::ElementRef

Reference to a gtopt element and one of its LP attributes.

struct gtopt::IndexRange

Specifies a set of index values for a time dimension.

struct gtopt::SumElementRef

Aggregation over multiple elements of the same type.