I am solving a model in GAMS. When running the optimzation model I want to save the optimal solution in a new varable. The heart of the code looks like this:
variables
xSave(t) 'saving the value of x at optimum'
x(t) 'variable';
SOLVE mymodel MINIMIZE fx Using NLP;
DISPLAY x.l;
When I exit at this point I can see that I have a solution; so the optimazation problem works fine!
I am trying to save the value of x in a new variable xSave and I have tried two methods:
Method1:
xSave(t)=x.l(t)
Method1:
loop(t, xSave(t)=x.l(t) ) ;
Both methods are returning the same error message:
A suffix is missing
What should I do?
You need a suffix on xSave as well as it is a variable, i.e.
xSave.l(t) = x.l(t);
Related
I'm trying to create the best linear regression model and my code is:
Daugialype2 <- lm(TNFBL~IL-4_konc_BL+ MCP-1_konc_BL+IL-8_konc_BL+TGF-β1_konc_BL)
summary(Daugialype2) #this code is working, I get a normal output
BUT
Then I want to introduce more variables to the model, e.g.
Daugialype2 <- lm(TNFBL~IL-4_konc_BL+ MCP-1_konc_BL+IL-8_konc_BL+TGF-β1_konc_BL+MiR_181_BL)
For unknown reasons, my output looks like this (even though without the MiR_181_BL variable, the output was good:
enter image description here
I don't know where is the problem - I don't get any error message. Could it be in the variable itself?
My variable looks like this (while others have less numbers after comma)
enter image description here
It's my very first model. Thank you for your answers!
is there any solution to solve a large system of equations in a program with the TI-nspire without typing all the variable names by hand?
For example, the function solve([1 2; 3 4]* [x; y] = 2,{x,y}) requires typing x,y manually. How is this done if the dimensions of the matrix can change?
I tried to use the function constructMat(x[i], i, j, 5, 1) which partly works but solve doesn't accept this function as variable as second argument.
Thanks for the help!!
I had this problem a while ago, i couldnt find any solution but to manually type the list of variables. Ive found the way to construct the list of unkowns (B_n):
i:=3:j:=4:B_n:=newlist(j+1) For i1,i,i+j:B_n[i1-i+1]:=expr("b"&string(i1)):endfor
with result: {b3,b4,b5,b6,b7}.
I dont remember exactly why this didnt work, i guess its the same reason (solve or zeros function will not accept this list as an argument)
In Dart/Flutter, suppose you have an instance a of Class Y.
Class Y has a property, property1.
You want to print that property using string interpolation like so:
print('the thing I want to see in the console is: $a.property1');
But you can't even finish typing that in without getting an error.
The only way I can get it to work is by doing this:
var temp = a.property1;
print ('the thing I want to see in the console is: $temp');
I haven't found the answer online... and me thinks there must be a way to just do it directly without having to create a variable first.
You need to enclose the property in curly braces:
print('the thing I want to see in the console is: ${a.property}');
That will then print the value of a.property.
It seems you can also do this, but it doesn't seem to be documented anywhere:
print('..... $a.$property1');
I am trying to run several files of code for an assignment. I am trying to solve an optimization problem using the "quadprog" function from the "optim" package.
quadprog is supposed to solve the optimization problem in a certain format and takes inputs H,f, A,b, Aeq, Beq, lb, ub.
The issue I am having involves my f which is a column vector of constants. To clarify, f looks like c*[1,1,1,1,1,1] where c is a constant. Quadprog seems to run my code just fine for certain values of c, but gives me the error:
error: index (_,49): but object has size 2x2
error: called from
quadprog at line 351 column 32
for other values of c. So, for example, 1/3 works, but 1/2 doesn't. Does anyone have any experience with this?
Sorry for not providing a working example. My code runs over several files and I seem to only be having problems with a specific value set that is very big. Thanks!
You should try the qp native Octave function.
You mention f is: c*[1,1,1,1,1,1] but, if c is a scalar, that is not a column vector. It seems very odd that a scalar value might produce a dimensions error...
I am trying to solve a problem involving the equating of sums of exponentials.
This is how I would do it hardcoded:
#NLconstraint(m, exp(x[25])==exp(x[14])+exp(x[18]))
This works fine with the rest of the code. However, when I try to do it for an arbitrary set of equations like the above I get an error. Here's my code:
#NLconstraint(m,[k=1:length(LHSSum)],sum(exp.(LHSSum[k][i]) for i=1:length(LHSSum[k]))==sum(exp.(RHSSum[k][i]) for i=1:length(RHSSum[k])))
where LHSSum and RHSSum are arrays containing arrays of the elements that need to be exponentiated and then summed over. That is LHSSum[1]=[x[1],x[2],x[3],...,x[n]]. Where x[i] are variables of type JuMP.Variable. Note that length(LHSSum)=length(RHSSum).
The error returned is:
LoadError: exp is not defined for type Variable. Are you trying to build a nonlinear problem? Make sure you use #NLconstraint/#NLobjective.
So a simple solution would be to simply do all the exponentiating and summing outside of the #NLconstraint function, so the input would be a scalar. However, this too presents a problem since exp(x) is not defined since x is of type JuMP.variable, whereas exp expects something of type real. This is strange since I am able to calculate exponentials just fine when the function is called within an #NLconstraint(). I.e. when I code this line#NLconstraint(m,exp(x)==exp(z)+exp(y)) instead of the earlier line, no errors are thrown.
Another thing I thought to do would be a Taylor Series expansion, but this too presents a problem since it goes into #NLconstraint land for powers greater than 2, and then I get stuck with the same vectorization problem.
So I feel stuck, I feel like if JuMP would allow for the vectorized evaluation of #NLconstraint like it does for #constraint, this would not even be an issue. Another fix would be if JuMP implements it's own exp function to allow for the exponentiation of JuMP.Variable type. However, as it is I don't see a way to solve this problem in general using the JuMP framework. Do any of you have any solutions to this problem? Any clever workarounds that I am missing?
I'm confused why i isn't used in the expressions you wrote. Do you mean:
#NLconstraint(m, [k = 1:length(LHSSum)],
sum(exp(LHSSum[k][i]) for i in 1:length(LHSSum[k]))
==
sum(exp(RHSSum[k][i]) for i in 1:length(RHSSum[k])))