## code – Spring State Machine is stucked in join state

I am using Spring State Machine current version.
The flow is as below

Fork -> Tasks (T1, T2, T3) -> Join.

T1, T2, and T3 each has 2 end states along with initial state, and one of an end states is transitioned based on respective event is sent.

I have .join() which has source(Tasks).target(next-state), and expecting flow to move to next-state when any end state for T1, T2, and T3 are reached, but this is not happening.

The last state I see is Tasks, instead of Join state, though end state is reached for T1, T2 and T3.

I also tried, to get join state specifying multiple source states (end states for T1, T2, T3) but it is not working.
if I do transition of initial state to end state for T1, T2 and T3 without any event (with local) then it works.

pl. let me know what could be an issue here.

## virtual machine – Running android emulator for games in a windows 10 VM on a windows 10 host

I am trying to get a setup where I’m running a game that is FAIRLY gpu intensive on an android VM within a VM on my local machine. I’ve looked into options like Virtualbox / VMWare Workstation, but neither have the option to allow for GPU (GTX1080) emulation that can handle the load. I have a powerful machine that should be able to handle this kind of thing from a computational standpoint (AMD 3900x, 64 gb of ddr5 ram) but I’m just not sure what I should be using in terms of VM to make this work.

I’ve tried VirtualBox -> Windows 10(1809) -> Nox 6.6.1.1 without any success.

Any recommendations or settings that might need to be enabled other than the normal hyper-v or bios options would be useful.

I started looking into QEmu but it didn’t seem like there was a good strategy for this as there wasn’t persistent storage for created VM’s

## How to conceive a Turing machine that is the intersection of the languages of two Turing machines?

What you ask might not be possible in general. If $$L(T)$$ denotes the set of words $$x$$ for which $$T(x)$$ accepts, and you do not have the additional assumption that $$M$$ and $$M’$$ recognize $$L(M)$$ and $$L(M’)$$, respectively, then you could choose:

• $$M$$ as a Turing machine that takes another Turing machine $$T$$ as input and accepts if and only if $$T$$ halts on empty input. (Notice that such a Turing Machine $$M$$ exists).
• $$M’$$ as a Turing Machines that recognizes the empty language.

Then, there is no Turing Machine $$T$$ that recognizes $$L(M) cup L(M’) = L(M)$$ since $$T$$ would solve the halting problem.

On the other hand, if you are fine with a Turing machine that accepts $$L(M) cup L(M’)$$ or if you have the additional assumption that $$M$$ and $$M’$$ recognize $$L(M)$$ and $$L(M’)$$, respectively, your problem is solved by a Turing machine that, on input $$x$$, operates as follows:

• Simulate $$M(x)$$ until it halts (possibly never).
• If $$M(x)$$ rejects, reject.
• Simulate $$M'(x)$$ until it halts (possibly never).
• If $$M'(x)$$ rejects, reject.
• Accept.

## machine learning – Books on scientific computing, efficent NN inference, and matrix multipication

I’m trying to learn more about how inference, matrix multiplication, and scientific computing (primarily with tensors/matrices). I’m not sure what the classics here are or what good sources are. I’m primarily looking for books but classic texts of any kind are welcome (including both papers, blogs, and articles on real world implementations).

I’d like to gain an understanding of both how to implement algorithms like GEMM as efficiently as BLAS implementations do and also how to perform inference on neural networks efficiently. When I say “efficiency” I mean both latency and throughput as is classically meant but I also mean energy efficiency as well. Energy efficiency seems to be covered less however.

What are good references/books in this area?

## Why is that the browser from my Virtual Machine is much slower than one from host?

When I try to navigate on the browser from my VM, it’s horribly slow and sometimes I get an error followed by abortion of it.

In comparison, the same browser works perfectly fine and fast on my host OS. Why is that?

## java – Javare cant create virtual machine no matter what fixes i try

this is what happened when i do the java -version and java -help commands Hi so im having problems with javare update 261. My problem is whenever u try to open anything that tries to open java virtual machine it gives me an error saying “can not create virtual machine” and i cant find a fix for this problem. im trying to run a program called battlescribe but everytime it says error cant create virtual machine. also when i do CMD and do java -version it says can not create virtual machine same with java -help, when i try to open the configure java app in my start menu it gives that same error. i have set _JAVA_OPTIONS to –Xmx1024M in enviroment variables. i have reinstalled java. I know ram isnt the issue cause i have 16 gbs of ram and its not getting anywhere near that amount. Also i can run the java version of minecraft fine. im also running 64 bit windowns 10. Also it is running as admin. I only have Javare installed.

Thanks in advanced if this isnt the right place to get help with this can someone point me in the right direction! i dont get why my questions are getting closed i dont know anymore details i even added more to what the problems are give me feedback at least!!!!!!!!

this is what happened when i do the java -version and java -help commands

this is the error that pop ups whenever i open anything that has to do with java ex a minecraft server the configure java or javares check for updates

## Should you let yourself ssh into every machine in your network?

This is a great question becuase this is a common concern I deal with. I will give some answers into what you should understand and what I would do.

1. Bastion Host or JumpBox is just two step so you can log in to the AWS via SSH port 22 or RDP port 3389 as you already know (for new users reading). It is a way to secure and to let your instances and not let your instances be in a public subnets (expose to the internet). Which means you need to access the jumpbox (Bastion Host) and then connect to the instance which is in a private subnet (no internet access). If you have multiple instances this will save you alot because you will only have to manage the security of the bastion host.

2. Opening ssh to the world is a very dangerous practice. For once when you create an instance in amazon it generates a keypair .pem so you can connect to your ec2 instances. The issue is managing the keys. If we talk about an organization as an example many users will have keys that will be an issue, and will fall out of hands if the instances are exposed to the internet and also its not a good practice to share keys between users for the same instances.

Resume:

So between these point what I would suggest if its that much level of security that you want is that you may want to look at something called SSM. SSM is an agent that is installed in your instances that monitor the instances, you can block all ssh access including in a provate subnet. And you can only connect trough it via the AWS Console (Picture below). You will not need a bastion host nor opening your instances up to the world via an ssh port. Which means you will save costs and also provide better security. Another point is you will have full to the instances (logs, healthcheck and control) trough the IAM which you can authorize which user or resource has accesss to it.

Observation : These are all in a private subnet and I use an Internet Gateway to download dependencies from yum.

## How to upgrade from Ubuntu 16.04 LTS to 20.04 (in virtual machine)

I am a very new Ubuntu user (in virtual machine because i use Windows 7 for non-ubuntu stuff R.I.P ME)
But i need to upgrade to 20.04 (and i use 16.04) but how to upgrade?

In VMWare.

## virtual machine – Single GPU Passthrough

So I’ve been spending my quarentine days “researching” on data privacy and all that crazy stuff on the Internet, when I found something that caught my attention: the ability of virtualizing Windows 10 and using it for gaming and whatnot.

Now, when I first saw this video, I realized that this wasn’t going to be an easy task, since in order to use your GPU on the guest OS you need to do GPU passthrough, and apparently you also need two GPUs for this to work… until I found this guide for single GPU.

However, I have the following questions:

1. Will there be any side effects on my PC after this?
2. If anything goes wrong, can I undo it? Or recover from my problem?
3. Is it more convenient to do this with a second GPU? – (Since I would use Linux to browse and stuff I wouldn’t mind not having a GPU for that host OS)
4. What OS is the best for this matter?

Somethings that I feel are important to mention:

• My (AMD) processor supports IOMMU, and I think it’s enabled.
• I also have Virtualization support. Last time I checked, this was enabled!
• I would like to do this with a GTX 1650 Super.
• I don’t have a second screen (I guess this is optional but felt like I had to write it down).
• The host OS could be either Manjaro or QubesOS (this one apparently is for virtualizing).
• The guest OS would be Windows 10 LTSC or any other W10 OS.

I’m not quite sure if any other requirement needs to be reviewed, but that’s all I have.

I’m not only doing this for privacy, but I also want to learn about Linux and well, virtualizing an OS.

So far I’ve seen that this sort of topics aren’t so talked about in here, and since I realized Stack Overflow wasn’t the right place, I thought this could be the right one.

Still, if I’m posting in the wrong place, I would appreciate if someone could tell me the right place where can I post my question.

## Existence of a loop in a Turing machine?

Consider a Turing Machine which (1) reads all its input and (2) accepts inputs arbitrarily large. Can we conclude that there must be a loop in the finite-state control as its inputs get larger?