Diagnostic Algebraic

Units: Yes/No
Default Value: False (0)
Validation Rule: False (0) or True (-1)
Description: Write LP files in algebraic format
Detail:

This setting instructs the Generic Writer to produce diagnostic files in an algebraic form, one for each optimization problem solved during the simulation.

Algebraic format summarizes the equations in the LP/MIP/QP problem so that each unique type of equation is represented by a single equation in a semi-algebraic format with its indices and coefficient ranges described. The format is not intended to be readable by optimization codes and cannot be used to reproduce the original optimization problem because it does not contain the full set of problem data, however it is useful for documenting the formulation.

Example System

Consider the simple three-area system in Figure 1. The data associated with this is listed in Tables 1-3.

Figure 1:Example three-area system

Table 1: Objects
System System - the system object
Generator Hydro.1 Hydro
Generator Hydro.2 Hydro
Generator Pumped.Hydro.3 Hydro
Generator Coal.1 Thermal
Generator Coal.2 Thermal
Generator Coal.3 Thermal
Generator CT.1 Thermal
Generator Nuclear.1 Thermal
Generator Firm.purchase.1 Contracts
Generator Firm.purchase.2 Contracts
Fuel Coal -
Fuel Gas.contract.1 -
Fuel Nuclear.Fuel -
Fuel Oil.No.2 -
Fuel Spot.gas -
Storage Pumped.Head.3 -
Storage Pumped.Tail.3 -
Purchaser Nonfirm.sale.1 -
Region North -
Region Southeast -
Region Southwest -
Node North -
Node Southeast -
Node Southwest -
Line East-West.tie -
Line Southeast.link -
Line Southwest.link -
Data File North Load -
Data File Southeast Load -
Data File Southwest Load -


Table 2: Memberships
Collection Parent Child
Generator.Fuels Coal.1 Coal
Generator.Fuels Coal.2 Coal
Generator.Fuels Coal.3 Coal
Generator.Fuels Coal.3 Oil.No.2
Generator.Fuels CT.1 Gas.contract.1
Generator.Fuels CT.1 Spot.gas
Generator.Fuels Nuclear.1 Nuclear.Fuel
Generator.Start Fuels Coal.2 Oil.No.2
Generator.Head Storage Pumped.Hydro.3 Pumped.Head.3
Generator.Tail Storage Pumped.Hydro.3 Pumped.Tail.3
Generator.Nodes Hydro.1 North
Generator.Nodes Hydro.2 North
Generator.Nodes Pumped.Hydro.3 North
Generator.Nodes Coal.1 Southwest
Generator.Nodes Coal.2 Southwest
Generator.Nodes Coal.3 Southwest
Generator.Nodes CT.1 Southeast
Generator.Nodes Nuclear.1 Southeast
Generator.Nodes Firm.purchase.1 Southwest
Generator.Nodes Firm.purchase.2 North
Purchaser.Nodes Nonfirm.sale.1 Southeast
Node.Region North North
Node.Region Southeast Southeast
Node.Region Southwest Southwest
Line.Node From East-West.tie Southeast
Line.Node From Southeast.link Southeast
Line.Node From Southwest.link North
Line.Node To East-West.tie Southwest
Line.Node To Southeast.link North
Line.Node To Southwest.link Southwest


Table 3: Properties
Collection Parent Child Property Value Data File Unit Band
Generators System Hydro.1 Fixed Load Method Relax When Zero
- 1
Generators System Hydro.1 Units 1
- 1
Generators System Hydro.1 Max Capacity 15
MW 1
Generators System Hydro.1 Min Stable Level 5
MW 1
Generators System Hydro.1 Commit 1
- 1
Generators System Hydro.1 Max Energy Week 2
GWh 1
Generators System Hydro.2 Fixed Load Method Relax When Zero
- 1
Generators System Hydro.2 Units 1
- 1
Generators System Hydro.2 Max Capacity 20
MW 1
Generators System Hydro.2 Min Stable Level 2
MW 1
Generators System Hydro.2 Max Energy Week 1
GWh 1
Generators System Pumped.Hydro.3 Fixed Load Method Relax When Zero
- 1
Generators System Pumped.Hydro.3 Units 1
- 1
Generators System Pumped.Hydro.3 Max Capacity 100
MW 1
Generators System Pumped.Hydro.3 Min Stable Level 20
MW 1
Generators System Pumped.Hydro.3 Pump Efficiency 90
% 1
Generators System Pumped.Hydro.3 Pump Load 100
MW 1
Generators System Pumped.Hydro.3 Min Pump Load 10
MW 1
Generators System Coal.1 Max Heat Rate Tranches 3
- 1
Generators System Coal.1 Fixed Load Method Relax When Zero
- 1
Generators System Coal.1 Units 1
- 1
Generators System Coal.1 Max Capacity 200
MW 1
Generators System Coal.1 Min Stable Level 1
MW 1
Generators System Coal.1 Load Point 1
MW 1
Generators System Coal.1 Load Point 100
MW 2
Generators System Coal.1 Load Point 200
MW 3
Generators System Coal.1 Heat Rate 11900
BTU/kWh 1
Generators System Coal.1 Heat Rate 10350
BTU/kWh 2
Generators System Coal.1 Heat Rate 10330
BTU/kWh 3
Generators System Coal.1 Start Cost 1500
$ 1
Generators System Coal.1 Forced Outage Rate 5
% 1
Generators System Coal.1 Mean Time to Repair 168
h 1
Generators System Coal.2 Max Heat Rate Tranches 3
- 1
Generators System Coal.2 Fixed Load Method Relax When Zero
- 1
Generators System Coal.2 Units 1
- 1
Generators System Coal.2 Max Capacity 100
MW 1
Generators System Coal.2 Min Stable Level 10
MW 1
Generators System Coal.2 Load Point 10
MW 1
Generators System Coal.2 Load Point 50
MW 2
Generators System Coal.2 Load Point 100
MW 3
Generators System Coal.2 Heat Rate 13100
BTU/kWh 1
Generators System Coal.2 Heat Rate 11550
BTU/kWh 2
Generators System Coal.2 Heat Rate 11530
BTU/kWh 3
Generators System Coal.2 Start Cost Time 24
h 1
Generators System Coal.2 Start Cost Time 58
h 2
Generators System Coal.2 Forced Outage Rate 5
% 1
Generators System Coal.2 Mean Time to Repair 168
h 1
Generators System Coal.3 Max Heat Rate Tranches 3
- 1
Generators System Coal.3 Fixed Load Method Relax When Zero
- 1
Generators System Coal.3 Units 1
- 1
Generators System Coal.3 Max Capacity 50
MW 1
Generators System Coal.3 Min Stable Level 5
MW 1
Generators System Coal.3 Load Point 5
MW 1
Generators System Coal.3 Load Point 10
MW 2
Generators System Coal.3 Load Point 50
MW 3
Generators System Coal.3 Heat Rate 14900
BTU/kWh 1
Generators System Coal.3 Heat Rate 12950
BTU/kWh 2
Generators System Coal.3 Heat Rate 12930
BTU/kWh 3
Generators System Coal.3 Start Cost 1500
$ 1
Generators System Coal.3 Start Cost 4000
$ 2
Generators System Coal.3 Start Cost Time 16
h 1
Generators System Coal.3 Start Cost Time 32
h 2
Generators System Coal.3 Forced Outage Rate 5
% 1
Generators System Coal.3 Mean Time to Repair 168
h 1
Generators System CT.1 Max Heat Rate Tranches 4
- 1
Generators System CT.1 Fixed Load Method Relax When Zero
- 1
Generators System CT.1 Units 1
- 1
Generators System CT.1 Max Capacity 10
MW 1
Generators System CT.1 Min Stable Level 1
MW 1
Generators System CT.1 Load Point 1
MW 1
Generators System CT.1 Load Point 3
MW 2
Generators System CT.1 Load Point 5
MW 3
Generators System CT.1 Load Point 10
MW 4
Generators System CT.1 Heat Rate Incr 16500
BTU/kWh 1
Generators System CT.1 Heat Rate Incr 16500
BTU/kWh 2
Generators System CT.1 Heat Rate Incr 16500
BTU/kWh 3
Generators System CT.1 Heat Rate Incr 16500
BTU/kWh 4
Generators System Nuclear.1 Max Heat Rate Tranches 2
- 1
Generators System Nuclear.1 Fixed Load Method Relax When Zero
- 1
Generators System Nuclear.1 Units 1
- 1
Generators System Nuclear.1 Max Capacity 100
MW 1
Generators System Nuclear.1 Min Stable Level 5
MW 1
Generators System Nuclear.1 Load Point 5
MW 1
Generators System Nuclear.1 Load Point 100
MW 2
Generators System Nuclear.1 Heat Rate Incr 10500
BTU/kWh 1
Generators System Nuclear.1 Heat Rate Incr 10500
BTU/kWh 2
Generators System Nuclear.1 Start Cost 1500
$ 1
Generators System Nuclear.1 Commit 1
- 1
Generators System Nuclear.1 Forced Outage Rate 5
% 1
Generators System Nuclear.1 Mean Time to Repair 168
h 1
Generators System Firm.purchase.1 Fixed Load Method Relax When Zero
- 1
Generators System Firm.purchase.1 Units 1
- 1
Generators System Firm.purchase.1 Max Capacity 20
MW 1
Generators System Firm.purchase.1 Min Stable Level 20
MW 1
Generators System Firm.purchase.1 Commit 1
- 1
Generators System Firm.purchase.1 Offer Quantity 20
MW 1
Generators System Firm.purchase.1 Offer Price 25.5
$/MWh 1
Generators System Firm.purchase.2 Fixed Load Method Relax When Zero
- 1
Generators System Firm.purchase.2 Units 1
- 1
Generators System Firm.purchase.2 Max Capacity 20
MW 1
Generators System Firm.purchase.2 Min Stable Level 20
MW 1
Generators System Firm.purchase.2 Commit 1
- 1
Generators System Firm.purchase.2 Offer Quantity 20
MW 1
Generators System Firm.purchase.2 Offer Price 24.3
$/MWh 1
Generator.Fuels Coal.3 Coal Ratio 0.95
-
1
Generator.Fuels Coal.3 Oil.No.2 Ratio 0.05
- 1
Generator.Start Fuels Coal.2 Oil.No.2 Offtake at Start 1000
MMBTU
Generator.Start Fuels Coal.2 Oil.No.2 Offtake at Start 500
MMBTU
Fuels System Coal Price 1.45
$/MMBTU 1
Fuels System Gas.contract.1 Price 1.7
$/MMBTU 1
Fuels System Nuclear.Fuel Price 1
$/MMBTU 1
Fuels System Oil.No.2 Price 2.2
$/MMBTU 1
Fuels System Spot.gas Price 1.8
$/MMBTU 1
Fuels System Spot.gas Max Offtake Day 0.5
BBTU 1
Storages System Pumped.Head.3 Max Volume 3
GWh 1
Storages System Pumped.Tail.3 Max Volume 3
GWh 1
Purchasers System Nonfirm.sale.1 Bid Quantity 5
MW 1
Purchasers System Nonfirm.sale.1 Bid Quantity 10
MW 2
Purchasers System Nonfirm.sale.1 Bid Price 10000
$/MWh 1
Purchasers System Nonfirm.sale.1 Bid Price 24.3
$/MWh 2
Regions System North Load Includes Losses Yes
Yes/No 1
Regions System North Load 0 NORTH.CSV MW 1
Regions System North VoLL 100
$/MWh 1
Regions System Southeast Load Includes Losses Yes
Yes/No 1
Regions System Southeast Load 0 SE.CSV MW 1
Regions System Southeast VoLL 80
$/MWh 1
Regions System Southwest Load Includes Losses Yes
Yes/No 1
Regions System Southwest Load 0 SW.CSV MW 1
Regions System Southwest VoLL 100
$/MWh 1
Lines System East-West.tie Max Flow 40
MW 1
Lines System East-West.tie Min Flow -40
MW 1
Lines System East-West.tie Loss Incr 0.04
- 1
Lines System East-West.tie Loss Incr Back -0.04
- 1
Lines System East-West.tie Wheeling Charge 2.5
$/MWh 1
Lines System East-West.tie Wheeling Charge Back 1.5
$/MWh 1
Lines System Southeast.link Max Flow 128
MW 1
Lines System Southeast.link Min Flow -128
MW 1
Lines System Southeast.link Loss Incr 0.03
- 1
Lines System Southeast.link Loss Incr Back -0.03
- 1
Lines System Southwest.link Max Flow 114.4
MW 1
Lines System Southwest.link Min Flow -114.4
MW 1
Lines System Southwest.link Loss Incr 0.05
- 1
Lines System Southwest.link Loss Incr Back -0.05
- 1
Data Files System North Load Filename 0 NORTH.CSV - 1
Data Files System Southeast Load Filename 0 SE.CSV - 1
Data Files System Southwest Load Filename 0 SW.CSV - 1


The data contained in the CSV files for system load is illustrated in Figure 2.

Figure 2: Load Data

LP File

If we run a simulation on this system with hourly resolution and weekly optimization step the resulting mixed-integer linear programming problem contains 15802 constraints, 13778 variables and 1808 integers and 44081 non-zero coefficients. The printed LP format file is 88800 lines long. Although it is possible to read this file it is not easy to understand the mathematical formulation in one glance. This is the purpose of the Algebraic format.

Algebraic File

By contrast, the Algebraic format file for this simulation has only 216 lines and is as follows:

        
\Problem name:  Base with Losses + Prosym Outages
\   variables: 13778   integers:  1808
\ constraints: 15802   nonzeros: 44081

Minimize
Obj:
   + [1.45, 2.2] GenFuel_*{1,…,168}
   + [-1.5, 2.5] LinFlow_*{1,…,2}{1,…,168}
   + 100000 NodUSE_*{1,…,168}
   + 1000 NodDump_*{1,…,168}
   + [-10000, -24.3] PurBuy_*{1,…,2}{1,…,168}
   + [10.5, 16.409569] GenLoad_*{1,…,168}
   + [-0.307924, 0.000177] GenFan_*{1,…,2}{1,…,168}
   + [2.252464, 30.893055] GenOn_*{1,…,168}{1,…,168}
   + [1100, 4000] GenStart_*{2,…,168, i ϵ (W,C)}{1}{2,…,168}
   + [24.3, 25.5] GenOffer_*{1}{1,…,168}

Subject To
FueMaxOffDay_*{1,…,7}:
   + FueMaxOffDayAct_*{1,…,168}
   <= 500
FueMaxOffDayActDef_*{1,…,168}:
   - FueMaxOffDayAct_*{1,…,168}
   + GenFuel_*{1,…,168}
   = 0
GenMaxEneWeek_*:
   + GenMaxEneWeekAct_*{1,…,168}
   <= [1000, 2000]
GenMaxEneWeekActDef_*{1,…,168}:
   - GenMaxEneWeekAct_*{1,…,168}
   + GenLoad_*{1,…,168}
   = 0
GenFuelDef_*{1,…,168}:
   - GenFuel_*{1,…,168}
   + [12.497222, 16.5] GenLoad_*{1,…,168}
   + [-1.176389, -0.117639] GenFan_*{1,…,2}{1,…,168}
   + 21.638889 GenOn_*{1}{1,…,168}
   = 0
GenRRay_*{1,…,2}{1,…,168}:
   + GenFan_*{1,…,2}{1,…,168}
   + [-1.333333, -0.818182] GenLoad_*{1,…,168}
   <= 0
GenBathtub_*{1,…,168}:
   + GenFan_*{1,…,3}{1,…,168}
   + [-199, -9] GenOn_*{1,…,168}{1,…,168}
   <= [0, 95]
NodNetInjDef_*{1,…,168}:
   + GenLoad_*{1,…,168}
   + [-1, 1] LinFlow_*{1,…,168}
   - NodNetInj_*{1,…,168}
   - 0.5 LinLoss_*{1,…,168}
   + NodUSE_*{1,…,168}
   - PurBuy_*{1,…,2}{1,…,168}
   - NodDump_*{1,…,168}
   + NodLossAdj_*{1,…,168}
   - GenPump_*{1,…,168}
   = [39, 192]
NodPwrBal_*{1,…,168}:
   + NodNetInj_*{1,…,168}
   = 0
LinNetFlowDef_*{1,…,168}:
   + [-1, 1] LinFlow_*{1,…,168}{1,…,168}
   = [40, 128]
LinLossDef_*{1,…,168}:
   + [-0.05, 0.05] LinFlow_*{1,…,2}{1,…,168}
   - LinLoss_*{1,…,168}
   = [-5.72, -1.6]
NodMaxUSE_*{1,…,168}:
   + NodUSE_*{1,…,168}
   - PurBuy_*{1,…,2}{1,…,168}
   <= [56, 192]
NodMaxDump_*{1,…,168}:
   - GenLoad_*{1,…,168}
   + NodDump_*{1,…,168}
   <= 0
NodLossDef_*{1,…,168}:
   + 0.5 LinLoss_*{1,…,168}
   - NodLoss_*{1,…,168}
   = 0
StoRecycle_*:
   + StoEndVol_*{168}
   = 3
StoBal_*{1,…,168}:
   + StoIniVol_*
   + [-1, 1] StoEndVol_*{1,…,168}
   - StoRel_*{1,…,168}
   + [-0.0009, 0.0009] GenPump_*{1,…,168}
   + 0.001 GenLoad_*{1,…,168}
   = 0
StoRelDef_*{1,…,168}:
   + 0.001 GenLoad_*{1,…,168}
   - StoRel_*{1,…,168}
   = 0
GenPmax_*{1,…,168}:
   + GenLoad_*{1,…,168}
   + [-200, -10] GenOn_*{1,…,168}{1,…,168}
   + GenFan_*{1,…,3}{1,…,168}
   (<=,=) [0, 100]
GenPmin_*{1,…,168}:
   + GenLoad_*{1,…,168}
   + [-20, -1] GenOn_*{1,…,168}{1,…,168}
   >= 0
GenMaxPump_*{1,…,168}:
   + GenPump_*{1,…,168}
   - 100 GenPumpOn_*{1,…,168}
   <= 0
GenMinPump_*{1,…,168}:
   + GenPump_*{1,…,168}
   - 10 GenPumpOn_*{1,…,168}
   >= 0
GenMaxPumpUnits_*{1,…,168}:
   + GenPumpOn_*{1,…,168}
   <= [0, 1]
GenUnits_*{1,…,168}:
   + GenOn_*{1,…,168}
   + GenPumpOn_*{1,…,168}
   <= [0, 1]
GenRating_*{1,…,168}:
   + GenLoad_*{1,…,168}
   + [-200, -10] GenOn_*{1,…,168}{1,…,168}
   <= 0
GenStartDef_*{1,…,168}{1,…,168}:
   + [-1, 1] GenOn_*{1,…,168}{1,…,168}
   + GenStart_*{1,…,168}{1,…,168}
   >= [-1, 0]
GenStartLb_*{1,…,168}{1,…,168}:
   + GenOn_*{1,…,168}{1,…,168}
   - GenStart_*{1,…,168}{1,…,168}
   >= 0
GenStartUb_*{1,…,168}{1,…,168}:
   + GenStart_*{1,…,168}{1,…,168}
   + GenOn_*{1,…,167}{1,…,167}
   <= 1
GenHrsDnLb_*{1}{1,…,168}:
   + [216, 250] GenOn_*{1}{1,…,168}
   + [-1, 1] GenHrsDn_*{1}{1,…,168}
   >= 1
GenHrsDnUb_*{1}{1,…,168}:
   + [-1, 1] GenHrsDn_*{1}{1,…,168}
   <= 1
GenHrsDnOn_*{1}{1,…,168}:
   + [216, 250] GenOn_*{1}{1,…,168}
   + GenHrsDn_*{1}{1,…,168}
   <= [216, 250]
GenStateDef_*{1}{1,…,168}:
   + [-1, 1] GenStart_*{1, i ϵ (W,C)}{1,…,168}{1,…,168}
   = 0
GenStartExpire_*{i ϵ (W)}{1}{1,…,168}:
   + GenStart_*{i ϵ (W)}{1}{1,…,168}
   + [0.017241, 0.03125] GenHrsDn_*{1}{1,…,167}
   + [-6.75, -4.310345] GenStartM_*{i ϵ (W)}{1}{2,…,168}
   <= [1.413793, 1.5]
GenStartMDef_*{i ϵ (W)}{1}{1,…,168}:
   + GenStart_*{i ϵ (W)}{1}{1,…,168}
   + GenStartM_*{i ϵ (W)}{1}{1,…,168}
   <= 1
GenStartNonPhys_*{i ϵ (C)}{1}{1,…,168}:
   + [-0.03125, -0.017241] GenHrsDn_*{1}{1,…,167}
   + GenStart_*{i ϵ (C)}{1}{2,…,168}
   + [-0.5, -0.413793] GenStartNonPhysM_*{i ϵ (C)}{1}{2,…,168}
   <= [-0.5, 0]
GenStartNonPhysMDef_*{i ϵ (C)}{1}{1,…,168}:
   + GenStart_*{i ϵ (C)}{1}{2,…,168}
   + GenStartNonPhysM_*{i ϵ (C)}{1}{2,…,168}
   <= [0, 1]
GenStartSOS11_*{1}{1,…,168}:
   + GenStart_*{i ϵ (W,C)}{1}{1,…,168}
   <= 1
GenFueMix_*{1,…,168}:
   + [-0.95, 0.95] GenFuel_*{1,…,168}
   = 0
GenOfferDef_*{1,…,168}:
   + GenLoad_*{1,…,168}
   - GenOffer_*{1}{1,…,168}
   = 0
GenCommitLb_*{1,…,168}:
   + GenLoad_*{1,…,168}
   >= [0, 5]
GenCommitUb_*{1,…,168}:
   + GenLoad_*{1,…,168}
   <= [0, 100]


Bounds
 FueMaxOffDayAct_*{1,…,168} free 
 GenMaxEneWeekAct_*{1,…,168} free 
 0 <= GenFuel_*{1,…,168} <= inf
 0 <= GenFan_*{1,…,3}{1,…,168} <= inf
 [0, 20] <= GenLoad_*{1,…,168} <= inf
 GenOn_*{1,…,168}{26,…,36} = 0
 [-128, 0] <= LinFlow_*{1,…,168}{1,…,168} <= [40, 128]
 NodNetInj_*{1,…,168} free 
 0 <= LinLoss_*{1,…,168} <= inf
 0 <= NodUSE_*{1,…,168} <= inf
 0 <= NodDump_*{1,…,168} <= inf
 NodLoss_*{1,…,168} free 
 NodLossAdj_*{1,…,168} = 0
 0 <= PurBuy_*{1,…,2}{1,…,168} <= [5, 10]
 StoIniVol_* = 0
 0 <= StoEndVol_*{1,…,168} <= 3
 0 <= StoRel_*{1,…,168} <= inf
 0 <= GenPump_*{1,…,168} <= inf
 0 <= GenStart_*{1,…,168, i ϵ (W,C)}{1,…,168}{1,…,168} <= [0, 1]
 0 <= GenHrsDn_*{1}{1,…,168} <= inf
 0 <= GenOffer_*{1}{1,…,168} <= 20

Generals
 0 <= GenPumpOn_*{1,…,168} <= inf
 0 <= GenStartNonPhysM_*{i ϵ (C)}{1}{1} <= inf

Binaries
 GenOn_*{1,…,168}{1,…,168}
 GenStartM_*{i ϵ (W)}{1}{1,…,168}
 GenStartNonPhysM_*{i ϵ (C)}{1}{2,…,168}

End

The algebraic format is formatted similarly to the familiar LP format with several sections:

  • Comments
  • Objective Function
  • Constraints
  • Bounds
  • Generals & Binaries

Variables and constraints in the problem are grouped by prefix, which is an abbreviation unique to each element. The prefixes form the start of the name of every variable and constraint in the LP file. For example, the prefix "GenFuel" is the fuel consumption by a generator, "LinFlow" is the flow on a transmission line, etc. The prefixes begin with a three letter abbreviation for the class the element pertains to e.g. "Gen" for Generator, "Lin" for Line, "Fue" for Fuel, etc, and are terminated by an underscore.. The complete list is in Table 2.

Table 2: Prefixes
Class
 Prefix
Generator Gen
Fuel Fue
Fuel Contract Fue
Emission Mis
Abatement Aba
Storage Sto
Waterway Wat
Power Station n/a
Physical Contract Phy
Purchaser Pur
Reserve Res
Battery Bat
Power2X P2X
Reliability n/a
Financial Contract Fin
Cournot n/a
RSI n/a
Region Reg
Pool n/a
Zone Zon
Node Nod
Load n/a
Line Lin
MLF n/a
Transformer Tra
Flow Control FC
Interface Int
Contingency n/a
Hub n/a
Transmission Right FCR
Heat Plant HPl
Heat Node HNo
Heat Storage HSt
Gas Field GFi
Gas Plant GPl
Gas Pipeline GPi
Gas Node GNo
Gas Storage GSt
Gas Demand GDe
Gas DSM Program GDSM
Gas Basin GBa
Gas Zone GZo
Gas Contract GCo
Gas Transport GTr
Gas Capacity Release Offer GCRO
Water Plant WPl
Water Pipeline WPi
Water Node WNo
Water Storage WSo
Water Demand WDe
Water Zone WZo
Water Pump Station WPS
Water Pump WPu
Vehicle Veh
Charging Station Cha
Fleet Fle
Company Com
Commodity Cmd
Process Pro
Facility Fac
Maintenance Mai
Flow Network n/a
Flow Node FNo
Flow Path FPa
Flow Storage FSt
Entity Ent
Market Mar
Constraint Con
Objective Obj
Decision Variable Var

The Comments section at the top of the file describes the original problem size.

The Objective Function section begins with one of the keywords minimize or maximize. Each term in the objective function is described in the format:

[ c1, c2] Prefix_*{indices}

where:

c1 and c2 are the smallest and largest objective function coefficient associated with the variable in the original problem respectively

Prefix_ is as described above

{indices} describes the indices for the variable and the index ranges applicable

For example the objective function term:

+ [10.5, 16.409569] GenLoad_*{1,…,168}"

refers to the Generator load variable. The "*" denotes where the name of each Generator would appear. The indices description "{1,…,168}" shows that the variable is indexed between 1 and 168 i.e. there is one such variable for each Generator and each hour of a week. The coefficient part "+ [10.5, 16.409569]" indicates that the coefficient values are all in the range 10.5 - 16.409569.

The constraints section begins with the keywords "Subject To". This section lists all the classes of constraint and the variable terms in them. This is formatted similarly to the objective function but each constraint is also shown with its name and indices, for example:

GenPmax_*{1,…,168}:
   + GenLoad_*{1,…,168}
   + [-200, -10] GenOn_*{1,…,168}{1,…,168}
   + GenFan_*{1,…,3}{1,…,168}
   (<=,=) [0, 100] w_i  0

The name of the constraint comes first and is separated from the rest of the constraint by a colon. In this case the constraint relates to the Generator class and is called "Pmax". It is indexed by time between 1-168 i.e. for each Generator there are 168 such constraints. The terms in the constraint are shown with their indices and coefficient ranges. The constraint sense (or direction) is indicated by the " (<=,=)" part. In this case it shows that some constraints are less-than-or-equal-to and other are equality constraints. Finally the right-hand side coefficient range is shown "[0, 100] ", which in this case shows that the right-hand-side ranges in value from 0-100.

The Bound section begins with the keyword "Bounds". It lists any lower or upper bounds on the variables. Any variable not listed here by default has bounds between zero and infinity. The special keyword "free" means that a variable has no bounds.

The final two sections are the Generals and Binaries. These sections simply list the variables that are general integers (can take any integer value between their bounds) or binary variables (must take the value zero or one only).

The algebraic format file ends with the keyword "End".