I would like to get some parameters from IPOPT, like for instance,
Using Ipopt
k = barrier_tol_factor
I know this doesn't work. Does anyone now how I can access thoes?
I tried with
Ipopt.barrier_tol_factor
It seems getting the current option value is tricky. But you can set this option and then the value should be known:
Ipopt.AddIpoptNumOption(solver, "barrier_tol_factor", 15.0)
BTW the default value is 10.0.
Related
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)
I found some problems where the optimization result from xpress does not follow the specified variable type. I set vartype=xp.binary when I create the xpress variables, but some of the results have values such as 0.13333, 0.36667, 0.5.
I found that this was caused by one of the constraints. When I disabled most of the constraints, the values are all binary. Then, I enabled the constraint one by one and found one set of constraints that is causing the value to be non-binary.
Has anyone observed this before? Any suggestion on how to enforce the variable value to be binary?
Thanks!
For sake of completeness, expanding Erwin Kalvelagen's comment into an answer:
Fractional values for integer variables usually happen when the problem is infeasible.
After solve() returns, you need to check attributes.mipstatus to make sure you actually have a solution available (see also the potential values for the MIP status here):
p = xp.problem()
...
p.solve()
print(p.getProbStatus(), p.getProbStatusString())
if p.attributes.mipstatus == xp.mip_solution or \
p.attributes.mipstatus == xp.mip_optimal:
print(p.getProbStatusString())
print(p.getSolution())
else:
print('No feasible solution', p.getProbStatusString())
Another way to get the problem status is function p.getProbStatus().
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])))
Is there any reason that this syntax shouldn't work in Qlikview load script??
Let v_myNumber = year(today());
Let v_myString = '2017-08';
If left($(v_myString),4) = text($(v_myNumber)) Then
'do something
Else
'do something else
End If;
I've tried both ways where I convert variable string to number and evaluate against the number variable directly and this way. They won't evaluate to equivalence when they should..
Left function is expecting a string as is getting something else as a parameter. As you are currently doing, the function will be called as Left(2017-08, 4) which is unhandle by QlikView.
If you use Left('$(v_myString)',4), it will evaluate as Left('2017-08', 4) as work as expected. Just adding quotes around the variable it should work.
Although QlikView calls them variables, they should really be seen as "stuff to replaced (at sometimes evaluated) at runtime", which is slightly different from a standard "variable" behaviour.
Dollar sign expansion is a big subject, but in short:
if you are setting a variable - no need for $().
if you are using a variable - you can use $(). depends on its context.
if you are using a variable that needs to be evaluated - you have to use $().
for example in a load script: let var1 = 'if(a=1,1,2)' - here later on the script you will probably want to use this variable as $(var1) so it will be evaluated on the fly...
I hope its a little more clear now. variable can be used in many ways at even can take parameters!
for example:
var2 = $1*$2
and then you can use like this: $(var2(2,3)) which will yield 6
For further exploration of this, I would suggest reading this
I can use "!(bind.property.ProductVersion)" to set for example the UpgradeVersion\#Minimum attribute. Works fine.
But now I want to set that attribute to something like:
"!(bind.property.ProductVersion.Major).!(bind.property.ProductVersion.Minor).0.0"
But that does not work.
I get this error: The UpgradeVersion/#Maximum attribute's value, '!(bind.property.ProductVersion.Major).!(bind.property.ProductVersion.Minor).0.0', is not a valid version. Legal version values should look like 'x.x.x.x' where x is an integer from 0 to 65534.
Any ideas how I can get this to work?
Regards, Jaap
Unfortunately, it appears the version attribute is only allowed to have a single binder variable to replace the whole string. It doesn't support the scenario you describe. However, it seems like it should. You could file a bug at http://wixtoolset.org/bugs