How would I know that dsolve numeric used which method to solve my non-linear bvp. Is there a way to find out about the method used by Maple 2019.
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I am really confused between Mid and Substring in VB.NET. Can anyone help me understand the difference with the help of a program? It will be really appreciated.
You can read the documentation for Mid and for Substring
The biggest difference arises from Mid being a legacy adapter function intended either to help VB6 code work if pasted into a vb.net project, or to provide VB6 programmers with some familiar functionality while they switch to using the modern .NET equivalent (Substring)
As a legacy function, Mid adopts the VB6 notions of strings being one-based indexing, rather than zero based (used by nearly everything else .NET) so anything you Mid should have a start parameter that is 1 greater than anything you Substring
Mid("Hellow World",1,5) 'returns Hello
Substring("Hellow World",0,5) 'returns Hello
Substring has a corollary, Remove, which removes chars after a certain point like Left used to. Ditching Left/Mid/Right in favour of Substring/Remove makes it easier to understand what to use/what will happen if the string passed in is in a right-to-left language
I would like to enter empty in place of Zero in numeric. i dont want use strings.
In Numeric field we can enter only NAN or INF but i want enter Empty.
There is no such thing as an Empty value for floating-point numerics in LabVIEW, just as there is no such thing in C#, C++, Java, or C. They all use the same IEEE standard to define floating-point values.
I opened an idea for this on the Idea Exchange: Create an "Optional" input type wrapper in the style of C++17's std::optional.
It was largely rejected because it's not a suitably useful thing for general use, but some ideas as to how you might implement it yourself were discussed there (don't miss the second page).
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])))
What is the reasoning for parsing an integer? For instance, Integer.Parse('variable'.text)
I see this a lot and while manipulating data for a calculator I am building I found that Val('variable'.text) was all I need to use "numeric" values.
So, my question is how does Integer.Parse() help me with regards to calculators?
Thanks!
I found that "Val('variable'.text)" was all I need
If that's the case then go ahead and use Val(). But be aware that it behaves differently than .Parse() (or, often preferably, .TryParse()) methods.
For example, what do you want to do if the user inputs "123 isn't 456"? Val() will (I think) return:
123 As Double
Or how about the input "123 456"? That would be:
123456 As Double
Do you want it to be a Double? Do you want it to throw an error because it's not purely numeric? Something else? The behavior you want should be reflected in the code you write. Use Val() for one set of behaviors, .Parse() for another.
I am solving an Integer program model with SCIP and I need to store the objective function value. I was wondering how I can get the objective function value after solving the IP model? can someone help me?
You can use SCIPgetPrimalbound() to get the best solution value.
Also, in the interactive shell the column "primalbound" will show the current best solution value and after the optimization process stops the primlalbound is also stated.
(Note, you might want to check whether a solution was found.)
If your problem is infeasible it 10^20 (SCIPs infinity value) is printed.
(If you want to see the objective function value and the solution values of each variable, you can enter display solution in the interactive shell, which will show all non-zeros solution values and the objective function value.)
See also http://scip.zib.de/doc/html/SHELL.php .