I have a question related to a transition in my statechart (see image above). I have a variable called palletInUse which is a boolean-type and changes between true and false. For one transition in my statechart I want it to change when the variable palletInUse has the value true. I have tried it with for example:
palletInUse == true;
and also tried different code like, equals and contentEquals etc. but nothing seems to work. Do you have a solution for this, seemingly simple problem?
Thanks in advance
The condition is not monitored constantly, only when something is changed in the agent. When you assign a new value to variable with common "=" Java operator, it is not caught by the AnyLogic engine. You need to call onChange() function after that. Then, the transition should be executed.
There are other ways to trigger the condition check without explicit onChange() call. You may find them in AnyLogic Help article.
BTW, you may specify just boolean variable as the condition, it is not required to compare it with true or false:
palletInUse
The condition is not evaluated if nothing is happening, for that reason you have to make something happen constantly to have your condition evaluated. A typical way of doing is as you see in the following pictures:
Related
I am doing a simulation of a production line, which is built through Excel.
Now there is one, which needs free setting of worker shifts for each machine, three shifts in total.
My idea is to create three different Schedules, representing each of the three shifts, and then in the ResourcePool, use the If statement to set up the use of each shift. As shown in the picture enter image description here
But it didn't work. If it is possable, Could you please tell me if there is something wrong with the Java statement or the idea is wrong.
If possible, could you please tell me how to set multiple schedules in ResourcePool?
Additions to the question：
The model is to do the evaluation of the production system and the shift of the workers is an important evaluation parameter. What I want to do is to enter the shift of the workers directly in the Excel sheet and ResourcePool recognizes and uses the corresponding Schedule.
I tried to generate the corresponding Schedule by code, but the Schedule of Resourcepool cannot be set dynamically. So I would like to try to manually input multiple Schedules into the model and then set the corresponding Schedule in ResourcePool by If statement like the image.
Thanks in advance
The first thing you need to know is that the location where you placed the code is a static parameter, thus it is only evaluated once, when the object is created and not checked continuously.
This is indicated by the little popup when you hover over the button that change the entry field from code to value
If it was dynamic it would state Dynamic Value instead of Static Value
Secondly, inside that field you must use a ternary operator, not an if statement, so that the result of the formula is a scheduled object, else you will get a "misplaced construct(s)" error
If you changed the code to
v_Shift == "Shift1" ?
s_Shift1 : v_Shift == "Shift2" ? s_Shift2 : s_Shift3
It will work BUT:
It will only be evaluated when the object is created and not again
Rather not use == on Strings, always use .equals(), on Strings it might work, and sometimes it might not. You can do some research as to why ;-)
Solution: You will have to use a function to change the schedule of the resource pool. Call this function whenever the v_Shift variable changes
I'm having an issue with conditions checking if an array contains a certain value.
I added a debug object to see the values when running. The following is my logic app designer view:
When running, the condition always evaluates to false.
This is what the run details show:
As seen in the above snippet, the Title 'General' is contained in the 'Array', yet the condition evaluates to false.
Why is this happening?
EDIT: see my answer, was a visual bug with the logic app designer view
It was probably a visual bug with the logic app designer view. In code view I saw the following:
I added the rest of the expression and it worked:
Per my understanding, it is not a bug. In your first screenshot, according to the icon
the "Title" is not shown as a variable as your mentioned in your answer("#variables('Title')"), so it always return "false" in the "If" condition.
If you want to get "true" result in your first screenshot, you can change the Array to the expression below:
string(variables('Array'))
the idea is to take a word and sub out all specified letters for another letter.
Any help on how to make this kind of function work?
The last array_push is not being called because you're returning before. Change it to:
array_push($stepsinchain, $subed);
return $subed;
Since $subed is never stored in the $stepsinchain array, due to the return being before, you're not able to access previous alternations.
array_push is also slower and not recommended when entering one element in an array. Instead, use
$stepsinchain[] = $subed;
It is also much faster as documented at http://www.php.net/manual/en/function.array-push.php#Hcom83388
I am trying to build a model that will have slightly different equations based on whether or not certain components exist (in my case, fluid ports).
A code like the following will not work:
parameter Boolean use_component=false;
Component component if use_component;
equation
if use_component then
component.x = 0;
end if;
How can I work around this?
If you want to use condition components, there are some restrictions you need to be aware of. Section 4.4.5 of the Modelica 3.3 specification sums it up nicely. It says "If the condition is false, the component, its modifiers, and any connect equations
involving the component, are removed". I'll show you how to use this to solve your problem in just a second, but first I want to explain why your solution doesn't work.
The issue has to do with checking the model. In your case, it is obvious that the equation component.x and the component component either both exist or neither exist. That is because you have tied them to the same Boolean variable. But what if you had don't this:
parameter Real some_number;
Component component if some_number*some_number>4.0;
equation
if some_number>=-2 and some_number<=2 then
component.x = 0;
end if;
We can see that this logically identical to your case. There is no chance for component.x to exist when component is absent. But can we prove such things in general? No.
So, when conditional components were introduced, conservative semantics were implemented which can always trivially ensure that the sets of variables and equations involved never get "out of sync".
Let us to return to what the specification says: "If the condition is false, the component, its modifiers, and any connect equations
involving the component, are removed"
For your case, the solution could potentially be quite simple. Depending on how you declare "x", you could just add a modification to component, i.e.
parameter Boolean use_component=false;
Component component(x=0) if use_component;
The elegance of this is that the modification only applies to component and if component isn't present, neither is the modification (equation). So the variable x and its associated equation are "in sync". But this doesn't work for all cases (IIRC, x has to have an input qualifier for this to work...maybe that is possible in your case?).
There are two remaining alternatives. First, put the equation component.x inside component. The second is to introduce a connector on component that, if connected, will generate the equation you want. As with the modification case (this is not a coincidence), you could associate x with an input connector of some kind and then do this:
parameter Boolean use_component;
Component component if use_component;
Constant zero(k=0);
equation
connect(k.y, component.x);
Now, I could imagine that after considering all three cases (modification, internalize equation and use connect), you come to the conclusion that none of them will work. If this is the case, then I would humbly suggest that you have an issue with how you have designed the component. The reason these restrictions arise is related to the necessity to check components by themselves for correctness. This requires that the component be complete ("balanced" in the terminology of the specification).
If you cannot solve the problem with approaches I mentioned above, then I suspect you really have a balancing issue and that you probably need to redefine the boundaries of your component somehow. If this is the case, I would suggest you open another question here with details of what you are trying to do.
I think that the reason why this will not work is that the parser will look for the declaration of the variable "component.x" that, if the component is not active, does not exist. It does not work even if you insert the "Evaluate=true" in the annotation.
The cleanest solution in my opinion is to work at equation level and enable different sets of equations in the same block. You can create a wrapper model with the correct connectors and paramenters, and then if it is a causal model for example you can use replaceable classes in order to parameterize the models as functions, or else, in case of acausal models, put the equations inside if statements.
Another possible workaround is to place two different models inside one block, so you can use their variables into the equation section, and then build up conditional connections that will enable the usage of the block with the choosen behaviour. In other words you can build up a "wrap model" with two blocks inside, and then place the connection equations to the connectors of the wrap model inside if statements. Remember to build up the model so that there will be a consistent system of quations even for the blocks that are not used.
But this is not the best solution, because if the blocks are big you will have to wait longer time for compilation since everything will be compiled.
I hope this will help,
Marco
You can also make a dummy component that is not visible in the graphical layer:
connector DummyHeatPort
"Dummy heatport to facilitate optional heatport. Use this with a conditional heatport by connecting it to the heatport. Then use the -DummyHeatPort.Q_flow in the thermal energy balance."
Modelica.SIunits.Temperature T "Port temperature";
flow Modelica.SIunits.HeatFlowRate Q_flow
"Heat flow rate (positive if flowing from outside into the component)";
end DummyHeatPort;
Then when this gets used in a two port model
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a heatport if use_heat_port;
DummyHeatPort dummy_heatport;
...
equation
flowport_a.H_flow + flowport_b.H_flow - dummy_heatport.Q_flow = storage
"thermal energy balance";
connect(dummy_heatport, heatport);
This way the heatport gets used if present but does not cause an error otherwise.
This might be an odd question, but I'm looking for a word to use in a function name. I'm normally good at coming up with succinct, meaningful function names, but this one has me stumped so I thought I'd appeal for help.
The function will take some desired state as an argument and compare it to the current state. If no change is needed, the function will exit normally without doing anything. Otherwise, the function will take some action to achieve the desired state.
For example, if wanted to make sure the front door was closed, i might say:
my_house.<something>_front_door('closed')
What word or term should use in place of the something? I'd like it to be short, readable, and minimize the astonishment factor.
A couple clarifying points...
I would want someone calling the function to intuitively know they didn't need to wrap the function an 'if' that checks the current state. For example, this would be bad:
if my_house.front_door_is_open():
my_house.<something>_front_door('closed')
Also, they should know that the function won't throw an exception if the desired state matches the current state. So this should never happen:
try:
my_house.<something>_front_door('closed')
except DoorWasAlreadyClosedException:
pass
Here are some options I've considered:
my_house.set_front_door('closed')
my_house.setne_front_door('closed') # ne=not equal, from the setne x86 instruction
my_house.ensure_front_door('closed')
my_house.configure_front_door('closed')
my_house.update_front_door('closed')
my_house.make_front_door('closed')
my_house.remediate_front_door('closed')
And I'm open to other forms, but most I've thought of don't improve readability. Such as...
my_house.ensure_front_door_is('closed')
my_house.conditionally_update_front_door('closed')
my_house.change_front_door_if_needed('closed')
Thanks for any input!
I would use "ensure" as its succinct, descriptive and to the point:
EnsureCustomerExists(CustomerID)
EnsureDoorState(DoorStates.Closed)
EnsureUserInterface(GUIStates.Disabled)
Interesting question!
From the info that you have supplied, it seems to me that setstate (or simply set, if you are setting other things than states) would be fine, though ensure is good if you want to really emphasize the redundancy of an if.
To me it is however perfectly intuitive that setting a state does not throw an exception, or require an if. Think of setting the state of any other variable:
In C:
int i;
i = 5; // Would you expect this to throw an exception if i was already 5?
// Would you write
if (i != 5)
i = 5;
// ?
Also it only takes about one sentence to document this behaviour:
The function does nothing if the
current state equals the requested
state.
EDIT: Actually, thinking about it, if it is really important to you (for some reason) that the user is not confused about this, I would in fact pick ensure (or some other non-standard name). Why? Because as a user, a name like that would make me scratch my head a bit and look up the documentation ("This is more than just an ordinary set-function, apparently").
EDIT 2: Only you know how you design your programs, and which function name fits in best. From what you are saying, it seems like your setting functions sometimes throw exceptions, and you need to name a setting function that doesn't - e.g. set_missile_target. If that is the case, I think you should consider the set_if, set_when, set_cond or cond_set names. Which one would kind of depend on the rest of your code. I would also add that one line of documentation (or two, if you're generous), which clarifies the whole thing.
For example:
// Sets missile target if current target is not already the requested target,
// in which case it does nothing. No exceptions are thrown.
function cond_set_missile_target ()
or function cond_set_MissileTarget ()
or function condSet_MissileTarget ()
or function condSetMissileTarget ()
ensure is not so bad, but to me it implies only that there is additional logic required to set the state (e.g. multiple states tied together, or other complications). It helps to make the user avoid adding unnecessary ifs, but it does not help much with the exception issue. I would expect an ensure function to throw an exception sooner than a set function, since the ensure function clearly has more responsibilities for, well, ensuring that this setting operation is in fact done right.
I'd go for ensure for the function you describe. I'd also use camelCase, but I suppose you may be in a language that prefers underscores.
You could always document (shock!) your API so that others don't make the mistakes you describe.