Please tell me how i can use the cdfpoisson function in GAMS? I wrote the code as below but i get the Unknown symbol error for M which is a variable that has been calculated from some other things.
Thanks
*Re(t,d)=Reliability of accepting emergency patients arriving at time period t on day d
$funclibin stolib stodclib
function cdfpoisson /stolib.CDFPoisson/;
Re(t,d)=cdfpoisson(M(t,d),Ltotal);
The code seems to be functional when adding the adequate set and parameter definitions as below. So your issue does not seem to be with the function but rather the definitions of set, parameters and/or variables. Please provide more detail if in need of a better answer.
set t "time" /
0
/;
set d "day" /
1
/;
parameter
Re(t,d) "Reliability of accepting emergency patients arriving at time period t on day d"
M(t,d)
Ltotal
;
M(t,d) = 1;
Ltotal = 5;
$funclibin stolib stodclib
function cdfpoisson /stolib.CDFPoisson/;
Re(t,d)=cdfpoisson(M(t,d),Ltotal);
execute_unload "test.gdx";
Related
I'm using MQL5 (my first code).
I want to use a script that uses MA, but first, I wanted to confirm the value to verify I'm doing correctly. Using a very basic code into script:
double x=0;
x = iMA(Symbol(),Period(),100,0,MODE_SMA,PRICE_CLOSE);
Alert("The actual MA from last 100 points of EURUSD actually is: " + x;
The expected value is near the actual price... 1.23456, but this function is returning 10.00000 or 11.0000.
I believe I'm missing something, and https://www.mql5.com/es/docs/indicators/ima helplink is not quite clear enough.
I already saw another similar function: MA[0] which seems to bring the moving average from specific candle, but, I don't know how to manage the Period range (100) or if is related to Close/Open variables on it. I didn't find any specific helplink to review.
Any ideas are very appreciated!!!
x should be int, it is a handler of the MA. So each indicator when created in MT5 receives its handler, and you can use it later to get what you need. If you need several MA's - create several handlers and give each of them different names (x1, x2 or add some sense). Expert advisors in the default build of MT5 are good examples on what to do.
The iMA function Returns the handle of a specified technical indicator, not the "moving average" value.
For example, to get the value of the Moving average you can use this (in MQ4):
EMA34Handler = iMA(NULL,0,34,0,MODE_EMA,PRICE_CLOSE);
EMA34Value = CopyBuffer(EMA34Handler, 0,0);
I have written an optimization problem in pyomo and need a constraint, which contains a summation that has a variable length:
u_i_t[i, t]*T_min_run - sum (tnewnew in (t-T_min_run+1)..t-1) u_i_t[i,tnewnew] <= sum (tnew in t..(t+T_min_run-1)) u_i_t[i,tnew]
T is my actual timeline and N my machines
usually I iterate over t, but I need to guarantee the machines are turned on for certain amount of time.
def HP_on_rule(model, i, t):
return model.u_i_t[i, t]*T_min_run - sum(model.u_i_t[i, tnewnew] for tnewnew in range((t-T_min_run+1), (t-1))) <= sum(model.u_i_t[i, tnew] for tnew in range(t, (t+T_min_run-1)))
model.HP_on_rule = Constraint(N, rule=HP_on_rule)
I hope you can provide me with the correct formulation in pyomo/python.
The problem is that t is a running variable and I do not know how to implement this in Python. tnew is only a help variable. E.g. t=6 (variable), T_min_run=3 (constant) and u_i_t is binary [00001111100000...] then I get:
1*3 - 1 <= 3
As I said, I do not know how to implement this in my code and the current version is not running.
TypeError: HP_on_rule() missing 1 required positional argument: 't'
It seems like you didn't provide all your arguments to the function rule.
Since t is a parameter of your function, I assume that it corresponds to an element of set T (your timeline).
Then, your last line of your code example should include not only the set N, but also the set T. Try this:
model.HP_on_rule = Constraint(N, T, rule=HP_on_rule)
Please note: Building a Constraint with a "for each" part, you must provide the Pyomo Sets that you want to iterate over at the begining of the call for Constraint construction. As a rule of thumb, your constraint rule function should have 1 more argument than the number of Pyomo Sets specified in the Constraint initilization line.
I need your help to solve this "Little" problem I'm having programming with GAMS.
In my objective function I have this member that is z = [...]-TWC(j)*HS(j).
Where HS(j)is a variable.
Now, TWC(j) should be a parameter that works like this:
TWC(j) = 0 when HS(j) < 1000
and
TWC(j) = 3.21 when HS(j) >=1000.
Any idea how to implement this in GAMS? my attempts all failed.
EDIT: this is what I tried I defined an equation called TWCup(j) that was:
TWCup(j)$(HS.l(j) >= 1000).. TWC(j) =e= 3.21;
Thanks ;)
Probably not relevant for the OP anymore (since the question is more than 3 years old), but maybe useful for someone else that looks at this question.
If TWC(j) is a function of your variable HS(j), it is not a parameter. It is another variable. So you should define TWC(j) as a variable and not as a parameter. This is probably the reason you were getting errors.
There are some ways to fix your problem: One is to actually turn TWC(j) into a variable. But this would turn your problem into non-linear which could be (or not) an issue. Also, this could need the use of binary variables, which could also become a problem (again, or not).
But I think this issue could be resolved with a different specification of the LP. The cost function f(HS(j)) = TWC(j)*HS(j) is linear by parts and convex, which you can represent in a standard LP using auxiliary variables (assuming you are minimizing).
* declare auxiliary variable
Variable
w(j);
* declare equations for linear by part cost function
Equation
costfun1(j)
costfun2(j);
;
* define costfun1 and costfun2
costfun1(j).. w(j) =g= 0;
costfun2(j).. w(j) =g= -3210 + 3.21*HS(j);
*redefine objective function (note that I changed to plus because I assumed this is a cost function that you are minimizing)
z = [...]+w(j)
This solution is very problem dependent. I assumed you were minimizing and I changed the sign in the objective function to '+'. If this was not the case, this would not work (would not be convex). Then we would need to check other approaches.
But the takeaway here is to stress that something that is a function of a variable is also a variable. But you may have options to reformulate your problem to address the problem.
I defined a set in GAMS to represent users number. I need to use the set multiple times to define transmission power for each user, the channel quality...etc. However, I think in GAMS you can not use the name of the set for different variables, My question is do I need to define a different set for each variable?
Code example:
set I number of users /i1,i2/ ;
Parameters
CP(I) circuit power per user /
i1 10
i2 10 /
h(I) channel quality /
i1 48.9318
i2 106.2280/ ;
Thank you in advance for any help or for any hints.
No, you don't need to define different sets if you always want to refer to the same elements (users in your case). It is actually the idea of sets to do exactly this. So, your example code is just right.
You can also look at a simple example like this one here: http://www.gams.com/modlib/libhtml/trnsport.htm
There you will see, that the sets i and j are used all over for different parameters, variables and equations.
I hope that helps,
Lutz
I am new to Z notation,
Lets say I have a function f defined as X |--> Y ,
where X is string and Y is number.
How can I get highest Y value in this function? Does 'loop' exist in formal method so I can solve it using loop?
I know there is recursion in Z notation, but based on the material provided, I only found it apply in multiset or bag, can it apply in function?
Any extra reference application of 'loop' or recursion application will be appreciated. Sorry for my English.
You can just use the predefined function max that takes a set of integers as input and returns the maximum number. The input values here are the range (the set of all values) of the function:
max(ran(f))
Please note that the maximum is not defined for empty sets.
Regarding your question about recursion or loops: You can actually define a function recursively but I think your question aims more at a way to compute something. This is not easily expressed in Z and this is IMO a good thing because it is used for specifications and it is not a programming language. Even if there wouldn't be a max or ran function, you could still specify the number m you are looking for by:
\exists s:String # (s,m):f /\
\forall s2:String, i2:Z # (s2,i2):f ==> i2 <= m
("m is a value of f, belonging to an s and all other values i2 of f are smaller or equal")
After getting used to the style it is usually far better to understand than any programming language (except your are trying to describe an algorithm itself and not its expected outcome).#
Just for reference: An example of a recursive definition (let's call it rmax) for the maximum would consist of a base case:
\forall e:Z # rmax({e}) = e
and a recursive case:
\forall e:Z; S:\pow(Z) #
S \noteq {} \land
rmax({e} \cup S) = \IF e > rmax(S) \THEN e \ELSE rmax(S)
But note that this is still not a "computation rule" of rmax because e in the second rule can be an arbitrary element of S. In more complex scenarios it might even be not obvious that the defined relation is a function at all because depending on the chosen elements different results could be computed.