Introduction to developing or migrating models to be compliant to the OpenMI Standard. OpenMI is an open standard which allows dynamic linking of numerical models, such as river models rainfall-runoff models and so on. See also: http://www.lictek.com

1. OpenMI Developers Training
Jan Gregersen
http://www.LicTek.com
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2. Simple River
Runoff Model Simple River
OutputExchangeItem InputExchangeItem
Quantity ID : Runoff
Quantity ID : Inflow
DataOperaiton : Distributed
ElementSet : Polygons ElementSet : Polyline
Y (km) 5 10
Y (km)
10
10 Node:0
Branch:0
Node:1
5
5
Branch:1
Node:2
Branch:2
Node:3
X (km)
X (km)
5 10
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3. How it works
Load components:
Query exchange items:
Add links:
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4. How it works
Prepare:
Run (GetValues):
Finish:
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5. The OpenMI standard
DHI - Water & Environment Jan Gregersen

6. Jan Gregersen 6

7. Migration of models
DHI - Water & Environment Jan Gregersen

8. Now What ???
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9. Org.OpenMI.Utilities
Org.OpenMI.Utilities.Buffer Buffers results from the engine core
SmartBuffer
Mapping of values associated to one array of
times /timespans to values represented on another
array of times/timespans
t t
Org.OpenMI.Utilities.Spatial
Mapping of values associated to
ElementMapper one ElementSet to be represented
on another ElementSet
Org.OpenMI.Utilities.Wrapper
Generic wrapper suited for time
SmartWrapper stepping model engines
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10. LinkableEngine features
• Provides a default implementation of the
ILinkableComponent interface
• Links bookkeeping
• Event handling
• Buffering
• Temporal interpolations, aggregations,
extrapolations
• Spatial interpolations, aggregations,
extrapolations
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11. Wrapper design pattern
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12. IEngine Interface
// -- Execution control methods (Inherited from IRunEngine) --
void Initialize(Hashtable properties);
bool PerformTimeStep();
void Finish();
//-- Time methods (Inherited from IRunEngine) --
ITime GetCurrentTime();
ITime GetInputTime(string QuantityID, string ElementSetID);
ITimeStamp GetEarliestNeededTime();
//-- Data access methods (Inherited from IRunEngine) --
void SetValues(string QuantityID, string ElementSetID, IValueSet values);
IValueSet GetValues(string QuantityID, string ElementSetID);
//-- Component description methods (Inherited from IRunEngine) --
double GetMissingValueDefinition();
string GetComponentID();
string GetComponentDescription();
// -- Model description methods --
string GetModelID();
string GetModelDescription();
double GetTimeHorizon();
// -- Exchange items --
int GetInputExchangeItemCount();
int GetOutputExchangeItemCount();
org.OpenMI.Backbone GetInputExchangeItem(int exchangeItemIndex);
org.OpenMI.Backbone GetOutputExchangeItem(int exchangeItemIndex);
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13. Inside the LinkableEngine
has SmartWrapper has
SmartInputLinkSet SmartOutputLinkSet
UpdateInput() UpdateBuffer()
1
GetValues()
access
has Link access 1
Link has
* *
SmartInputLink SmartOutputLink
UpdateInput() has UpdateBuffer()
GetValues()
has
SmartBuffer ElementMapper
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14. GetValues()
Model B Model A
GetValues(time, LinkID)
GetValues(time, LinkID)
1. Update with input from linked models
2. Perform time step and fill internal buffers
While (CurrentTime < time & State is “Not Busy”)
3. Map values in time and space
Return values
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15. GetValues()
Model B Model A
GetValues(time, LinkID)
GetValues(time, LinkID)
1. Update with input from linked models
2. Perform time step and fill internal buffers
While (CurrentTime < time & State is “Not Busy”)
3. Map values in time and space
Return values
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16. GetValues()
Engine Smart A Smart A Smart A Smart
A Smart
Model B Model A AIP Output Output Element InputLink Input
Buffer
Access LInkSet LInk Mapper Set Link
GetValues(tl LinkID)
GetCurrentTime()
IsBusy = true UpdateInput(ct)
UpdateInput(ct)
GetValues(ct,LinkID)
SetValues(Quantity,LocationID,Values)
For each Input Link
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17. GetValues()
Model B Model A
GetValues(time, LinkID)
GetValues(time, LinkID)
1. Update with input from linked models
2. Perform time step and fill internal buffers
While (CurrentTime < time & State is “Not Busy”)
3. Map values in time and space
Return values
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18. GetValues()
Engine Smart A Smart A Smart A Smart
A Smart
Model B Model A AIP Output Output Element InputLink Input
Buffer
Access LInkSet LInk Mapper Set Link
PerformTimeStep()
UpdateBuffers()
UpdateBuffer()
Getvalues(Quantity,LocationIDs)
Addvalues(time, valueSet)
For each output link
IsBusy = false
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19. GetValues()
Model B Model A
GetValues(time, LinkID)
GetValues(time, LinkID)
1. Update with input from linked models
2. Perform time step and fill internal buffers
While (CurrentTime < time & State is “Not Busy”)
3. Map values in time and space
Return values
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20. GetValues()
Engine Smart A Smart A Smart A Smart
A Smart
Model B Model A AIP Output Output Element InputLink Input
Buffer
Access LInkSet LInk Mapper Set Link
GetValues(time, LinkID)
GetValues(time)
GetValues(time)
MapValues(inpuValues)
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21. IEngine Interface
// -- Execution control methods (Inherited from IRunEngine) --
void Initialize(Hashtable properties);
bool PerformTimeStep();
void Finish();
//-- Time methods (Inherited from IRunEngine) --
ITime GetCurrentTime();
ITime GetInputTime(string QuantityID, string ElementSetID);
ITimeStamp GetEarliestNeededTime();
//-- Data access methods (Inherited from IRunEngine) --
void SetValues(string QuantityID, string ElementSetID, IValueSet values);
IValueSet GetValues(string QuantityID, string ElementSetID);
//-- Component description methods (Inherited from IRunEngine) --
double GetMissingValueDefinition();
string GetComponentID();
string GetComponentDescription();
// -- Model description methods --
string GetModelID();
string GetModelDescription();
double GetTimeHorizon();
// -- Exchange items --
int GetInputExchangeItemCount();
int GetOutputExchangeItemCount();
org.OpenMI.Backbone GetInputExchangeItem(int exchangeItemIndex);
org.OpenMI.Backbone GetOutputExchangeItem(int exchangeItemIndex);
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22. Wrapper design pattern
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23. Migration steps
• Change your engine to a dll
• Implement Initialize, PerformTimeStep
and Finish
• Create the EngineDllWrapper class
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24. Wrapper design pattern
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25. Migration steps
• Create your MyEnigneWrapper
• Implement Initialize and Finish
• Implement remaining Ienigne methods
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26. Jan Gregersen 26

27. The ElementMapper
Ground water River Model
Model
GetValues(time, link)
Calculate
Return values
Has Link Has
ElementSet
Quantity
“GW Recharge”
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28. Spatial mapping
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29. ElementMapper
Org.OpenMI.Utilties.Spatial
ElementMapper
Initialise(string methodDescription, IElementSet fromElements, IElementSet toElements)
IValueSet MapValues(IValueSet inputValues)
 r1   m11 m12 m13 . m1n  x1 
    
 r2   m21 m22 m23 . m2 n  x2 
r m m32 m33 . m3n  x3 
 3   31  
 .  . . . . .  . 
r  m mmn  xn 
 m   m1 mm 2 mm3 .  
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30. Element Mapping
RE1
 1 1/ 3 0 
 
RE1
 0 2 / 3 1/ 2
GE1 GE2
A
0 
RE3
0 0
 
 0 0 1/ 2
GE3 GE4
 
I  L A
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31. Element
• ID Based “Node127”
• Point (x1,y1)
• Line (x1,y1) (x2,y2)
• Polyline (x1,y1) (x2,y2) (x3,y3) (x4,y4)
(x1,y1) (x5,y5)
• Polygon (x4,y4)
(x2,y2)
(x3,y3)

32. ElementSet example
H
Q H
H
Q Q
H
Q H H
Q Q
H
H Q
Q H
Q
H
Q
H
Q
H

33. Quantity
• ID ( “Runoff” )
• Description ( “Rainfall runoff” )
• Dimension ( e.g. L3 T-1 )
– GetPower ( <dimensionBase> )
• Unit:
– ID ( “CFS” )
– Descr ( “Cubic feet per second “ )
– ConversionFactorToSI ( 0,0283168439 )
– OffsetToSI ( 0 )

34. ExchangeItem
• InputExchangeItem
– Quantity
– ElementSet
• OutputExchangeItem
– Quantity
– ElementSet
– [ DataOperations
• ID
• Arguments ]

35. Unidirectional link
« t rae
in f c»
e « t rae
in f c»
e
Re oe:
ivr dl
M Rm e:
Ro l
d
M Pg m
a r r
in o a I in b C pnn
L k le o oet
a m I in b C pnn
L k le o oet
a m
GVlusim t ,lin D r gr in
e a e t e 1 k = ige k
t ( = I T L )
[]
1
[]
2 GVlusim R t e _t lin D RRe
e a e t e M + d k = t ivr
t ( = im , I Ro )
Pro T e t p
e r im e
f m S
[]
3
r t r VluSt R o
e n a ee u f
u : nf { h Rt e Rt e _t
w ile Rim< M + d
im }
Pro T e t p
e r im e
f m S
{ h Rt e t }
w ile M <1
im
r t r VluSt Re lo
e n a e e ivr w
u : F

36. Bidirectional links
«interface» «interface»
RiverModel : GroundW aterModel :
MainProgram ILinkableComponent ILinkableComponent
GetValues(t2,TriggerLink)
[1]
GetValues(time=t1, linkID=QtoRiver)
[2]
GetValues(time=t2, linkID=HtoGW)
[3] Extrapolate (t2)
[4]
return extrapolated ValueSet: HtoGW (t2)
PerformTimeStep (t2)
[5]
return interpolated ValueSet QtoRiver (t1)
PerformTimeStep (t1)
[6]
GetValues(time=t2, linkID=QtoRiver)
[7]
return ValueSet QtoRiver (t2)
PerformTimeStep (t2)
return ValueSet Hriver (t2)
RiverModel us time s
es tep t1, GroundwaterModel us time s
es tep t2

37. IterationController «interface» «interface»
: RiverM odel : GroundWaterM odel :
ILinkableCom ponent ILinkableCom ponent ILinkableCom ponent
M ainProgram
GetValues(tim e=t2, linkID=H_SW)
KeepCurrentState
[1] RiverState_t_begin
KeepCurrentState
GWState_t_begin
[2] InitialGuess(QtoGW)
RestoreState(RiverState_t_begin)
[3]
RestoreState(GWState_t_begin)
[4]
GetValues(tim e=t2, linkID=H_GW)
GetValues(time=t2, linkID=QtoGW)
QtoGW_guess
H_GW
[5] GetValues(tim e=t2, linkID=H_SW)
GetValues(tim e=t2, linkID=QtoGW)
QtoGW_guess
H_SW
Evaluate
[6]
NewGuess(QtoGW)
{untill QtoGW is stabilized}
result: H_SW
[7]

38. «interface» «interface»
RiverModel : RR model :
MainProgram ILinkableComponent ILinkableComponent
User :
IListener
Start
GetValues(time=t1,TriggerLinkID)
[1]
OnEvent(SourceAfterGetValuesCall)
return computation thread
GetValues(time=t1,linkID=QtoRiver)
[2]
OnEvent(SourceAfterGetValuesCall)
return computation thread
PerformTimeStep((_dt))
[3] OnEvent(DataChanged)
return computation thread
OnEvent(SourceBeforeGetValuesReturn) {until RRtime=t1}
Pause
[4]
Resume
[5] return computation thread
return ValueSet(QtoRiver, t1)
OnEvent(TargetAfterGetValuesReturn)
[6] return computation thread
PerformTimeStep(RM_dt)
OnEvent(DataChanged)
[7]
OnEvent(SourceBeforeGetValuesReturn)
return computation thead
[8] return ValueSet(t1)

39. Persistency
• OMI File
– For identifying a linkable component
• Composition
– In org.OpenMI.Utilities.Configuration
– Holds administration of links and linkable
components
– Can be run
– Can be written and read to / from xml

40. Exercise 9:
Unit Conversion
Step 1
Open the DataCombinator
Step 2
Adjust the code of GetValues so that it delivers data in the right
unit
Step 3
Adjust the test program to ask for a quantity which has a
conversion factor not equal to one
Step 4
Identify a value as missing value (e.g. -999) and adjust the
input. Make sure this value is processed correctly.
Step 5
Test the program using NUnit