# Questions tagged [simulation]

Questions about simulating one model in another. This includes simulating reality in any model, or simulating a machine model with Turing machines.

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### definition of P-samplable distribution that allows non-binary fractions

Arora and Barak (in chapter 18, on average-case complexity) define a polynomial-time samplable (or P-samplable) distribution $D$ (actually a family $\{D_n\}$, for each output length $n$) as having an ...
581 views

### Are the halting problem proofs refuted by software engineering?

Can D simulated by H terminate normally? The x86utm operating system based on an open source x86 emulator. This system enables one C function to execute another C function in debug step mode. When H ...
1 vote
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### Learn computer architecture and organisation via an oversimplified machine

I wish to learn CO&A (computer organisation and architecture) from scratch via some toy system and its simulator. I found the following resource: Toy Machine developed at Princeton University. Toy ...
494 views

### Does the Linz Ĥ applied to ⟨Ĥ⟩ correctly transition to its final reject state?

Applying a Simulating Halt Decider to the Linz Halting Problem Proof A simulating (at least partial) halt decider correctly predicts whether or not its correctly simulated input can possibly reach its ...
2k views

### Prove that turing machines and the lambda calculus are equivalent

It is known that a turing machine and the lambda calculus are equivalent in power. I now want to try to prove this myself. I think proving that the lambda calculus is at least as powerful as a turing ...
48 views

### What is the most efficient way to represent an directed dynamic massive 3D graph?

I know that there are many techniques to represent graphs. Suppose I have a directed massive 3D graph with 100,000 nodes at maximum. Suppose the graph looks somewhat like the following: Suppose each ...
1 vote
49 views

### How to simulate a Discrete Event Simulation model with a real-time server?

My Problem is having to work with real-time server in a DES model. I have the following situation: I want to build a discrete event simulation model (Using event scheduling world view). However, this ...
49 views

### Are there any probabilistic models of computation that can strongly simulate themselves?

I was reading this question over on the quantum computation stackexchange, and the top answer stated that you can't (strongly) simulate even a probabilistic turing machine, on itself. I was just ...
1 vote
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### Can all non-quantum physical systems be efficiently simulated on a classical computer?

Is it true that simulating classical physical systems is in P, i.e. can be done efficiently on Turing machines or are there known exceptions? I'm thinking of chaotic systems but I'm also curious more ...
1 vote
1k views

### Prove Halting on all Inputs is not in RE simulation

I don't understand why when proving if Halting on all inputs problem si not in RE using the complement of the halting problem, I have to take a turing machine and simulate the machine M(the machine ...
37 views

### are computer errors inevitable?

this is my First post,I apologize for my ignorance. The question is: Could a programmer (human or Ai) with all the computing power and infinite time create a simulation of a world with our same laws ...
1 vote
151 views

### Prove the equivalence of the modified Turing Machines and the standard Turing Machines

We have a Turing Machine that cannot write the same symbol it has read in a transition, meaning it should always alter the symbol when passing it. How can we prove that such machines have equal ...
1 vote
204 views

### A turing machine L takes a machine <M> which has to halt at for least n Inputs

I've been wondering about this problem for a while: Say we have L = { <M>, n | M has to halt for at least n Inputs} and multitapes are simulating various inputs bla bla How do I count how many ...
71 views

### Is there any hope for real "simulated machines" in our lifetime?

Without going into details about my life's story, here's the basic facts: I grew up with 386 and 486 and Pentium PCs running MS-DOS 5 (I believe), Windows 3.1 and Windows 95, a well as various game ...
54 views

### Are sample memory access traces/dumps available, and where?

I am looking for a realistic physical memory access trace/dump of significant, but not insane, length (on the order of 1M accesses) for the purpose of cache simulation. Preferably for a 16-bit or 32-...
4k views

### How can I convert the Turing machine the recognizes language $L$ into an unrestricted grammar?

According to this Wikipedia article, unrestricted grammars are equivalent to Turing machines. The article notes that I can convert any Turing machine into an unrestricted grammar, but it only shows ...
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### What was the original paper that showed a simulation of turing machines via circuits?

It is a very standard construction in most complexity theory courses to turn a turing machine into a circuit. I thought this was due to Cook, but it looks like he did the reduction to SAT not through ...
85 views

### How can I convert a Grammar to NFA?

Hello I have a task where I´m stucking at. I have to convert a Grammar to NFA. I have these information: G=(V,T,P,S) V={S}, T{0} and S -> 0S S -> 0 I can´t ...
2k views

### Does every turing machine have an equivalent, single-state, n-tape turing machine?

Is it the case that every problem computable by a Turing Machine can also be represented by some kind of equivalent n-tape Turing Machine which one has only one state? (We can assume that the accept ...
61 views

### What algorithm to use for substractive machining RT simulation?

For a CAM (Computer Aided Manufacturing) software, and more specifically, for the simulation of the subtractive manufacturing, I would like to understand how to design the representation. In ...
26k views

### Convert CFG to PDA

Is there any set of rules or methods to convert any context free grammar to a push down automata? I already found some slides online but I wasn't able to understand them. In slide 10 he speaks ...
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### What would you do if the author of a published CS article does not respond to code requests? [closed]

Since reproducibility is a major principle or basic norm of scientific experiments, simulations, and computations, what would you do or what to do if the author of a published CS article does not ...
44 views

### Understanding the simulate of an IF loop program through a LOOP program

We have the following operation $\text{IF} \ x_i =0 \ \text{THEN} \ P \ \text{END}$. I want to simulate this using a $\text{LOOP}$ program. Here is what I have: \text{IF} \ x_i = 0 \ \text{THEN} \ P ...
244 views

### Is NP in NP/Poly?

The answer is yes, NP/poly is defined as the class of problems solvable in polynomial time by a non-deterministic Turing machine that has access to a polynomial-bounded advice function--the advice ...
32 views

### single circuit simulating multiple Turing machines

You can simulate polynomial time Turing machines with polynomial size circuits, can you simulate multiple poly time TMs with a single poly size circuit?
1 vote
61 views

### Why does a kalman filter work better in a simulation than in real life?

I am trying to use a classical Kalman filter for getting indoor location. I am using geolocation API of HTML to get latitude, longitude, position accuracy and speed. I am also using the smartphone's ...
62 views

### Are objects appropriate for modeling the real world?

First of all, I know objects are not meant to model the real world, although they have been marketed as such and perhaps that was an intention at some point. Here I say 'modeling the real world' in a ...
896 views

### What is the difference between a simulator, emulator, and cross compiler?

As far as I understand, cross compilers, emulators, and simulators are all ways that one computer system to be able to behave like or run another computer system. What is the difference between these ...
62 views

### Creating An Artificial Universe

This is a general question and one that has bugged me for a long time. I want to start working on an artificial universe, not something too ambitious but more of a basic concept. What I have in mind ...
120 views

### What subfields in computer sciences may one study without learning Object Oriented Programming?

What subfields in computer sciences may one study without learning Object Oriented Programming or is there some kind of degree in Computer Science without the OOP knowledge requirement? Is there a ...
42 views

### Encoding huge number of tape-symbols of a turing machine in the simulation of the turing-machine using real computer

I was going through the classic text "Introduction to Automata Theory, Languages and Computation" by Hopcroft,Ullman,Motwani where I came across the simulation of a turing machine using a real ...
1 vote
767 views

### Queries regarding simulation of multi-tape turing machine using single tape turing machine

I was going through the classic text "Introduction to Automata Theory, Languages, and Computation" by Jeffrey Ullman,John Hopcroft and Rajeev Motwani, where I came across the simulation of MULTI-TAPE ...
267 views

### Why can’t you simulate a Turing machine with a one-stack PDA by messing with the stack?

I have heard that a matrix can be modeled as just an one array by declaring increasingly large spaces to be from the second array, and that the least you need for a Turing machine is just a PDA with ...
1k views

### What does "fast-forwarding" mean in the context of CPU simulation?

I'm using a simulator for my thesis and I've come across the term "Fast-forwarding" but I have found no definition anywhere in the documentation or online. From a pdf I've been reading about the ...
83 views

### Regular grammars

I am fairly new to automata, regular expressions and regular grammar. I am struggling to understand how to define the regular expression (abc)* into one or several regular grammar expressions. ...
1 vote
318 views

### Priority Queue Using Stack

Can one build a priority queue using stacks, such that the priority queue has the same complexity for each operation. Could it be done? If so how? If not what is the best solution that can be done? ...
198 views

### Does the callback concept of programming have any basis in computer science?

Although I seriously code with computer languages in general since 2010 and as an amateur programmer with programming languages in particular since 2015 (primarily Bash and JavaScript imperative ...
122 views

### Does the pigeonhole principle rule out the possibility of losslessly simulating a universe the size of our own?

Say you had a very powerful computer and wanted to run a completely lossless simulation of a universe approximately the same size as our own: $10^{80}$ particles. Each particle in the simulation has ...
1k views

### Would creating a complete computer simulation of the human brain prove the Church-Turing thesis?

According to Wikipedia, the Church-Turing thesis "states that a function on the natural numbers is computable by a human being ignoring resource limitations if and only if it is computable by a Turing ...
150 views

### Prof Knuth's MIX computer - Card Reader and illegal characters

I'm reading through Knuth's "The Art of Computer Programming" volume 1 (3rd edition), with the goal of understanding the complete workings of his hypothetical MIX computer in order to implement MIX in ...
1 vote
110 views

### Simulations between Turing machines

I've got a question. How can i simulate Turing machine with a double-sided infinite tape by a Turing machine with one-sided infinite tape? The condition is, that the simulation of one step of the ...
435 views

### How would one simulate the law of conservation of energy?

I'm new to computer science, but I've studied physics for a while. I'm just curious, if one wanted to make a simulation of the law of conservation of energy, on a large scale, how would it be done? ...
3k views

### Thompson's Construction Algorithm produces a different NFA

My teacher asked me to convert the regular expression $(a | b)^*$ to an NFA using Thompson's algorithm – well, I'm well aware of how this algorithm works, but since I'm not good at memorising details, ...