NMinimize differential evolution: how do search points and initial points really work?

I am puzzled by the settings of a specific method for NMinimize called DifferentialEvolution, given for example here. The settings include both "SearchPoints", or the size of the population of evolving points, and "InitialPoints", or the initial population(?). What I don’t quite understand is that "SearchPoints" can be set to a value different from the number of specified "InitialPoints" and NMinimize will often happily proceed, and sometimes it won’t.

What might be happening under the hood? If there are less "InitialPoints" than there are "SearchPoints", will the population be filled up with random points to meet the specified number of "SearchPoints" before evolution begins or does it proceed with a population that is in fact smaller than "SearchPoints"? What about the opposite case?

Here is an example where we give much less "InitialPoints" than there are "SearchPoints".

Clear[f, c, v, x1, x2, y1, y2, y3]; f = 2 x1 + 3 x2 + 3 y1/2 + 2 y2 - y3/2; c = {x1^2 + y1 == 5/4, x2^(3/2) + 3 y2/2 == 3, x1 + y1 <= 8/5,     4 x2/3 + y2 <= 3, y3 <= y1 + y2, 0 <= x1 <= 10, 0 <= x2 <= 10,     0 <= y1 <= 1, 0 <= y2 <= 1,     0 <= y3 <= 1, {y1, y2, y3} \[Element] Integers}; v = {x1, x2, y1, y2, y3};  NMinimize[{f, c}, v, Method -> "DifferentialEvolution"] (*{7.66718, {x1 -> 1.11803, x2 -> 1.31037, y1 -> 0, y2 -> 1, y3 -> 1}}*)  points = 5; searchpoints = 50; listpoints = {RandomReal[{0, 10}, points],  RandomReal[{0, 10}, points], RandomReal[{0, 1}, points],  RandomReal[{0, 1}, points],  RandomReal[{0, 1}, points]}\[Transpose];  NMinimize[{f, c}, v,   Method -> {"DifferentialEvolution", "SearchPoints" -> searchpoints,  "InitialPoints" -> listpoints}] (*{7.66718, {x1 -> 1.11803, x2 -> 1.31037, y1 -> 0, y2 -> 1, y3 -> 1}}*) 

If there are more "InitialPoints" than there are "SearchPoints", NMinimize sometimes works and sometimes doesn’t, depending on the value of the random seed for instance.

Can an 8th level Monk/Barbarian (Path of the beast) really make 5 attacks per turn?

In Tasha‘s Cauldron of Everything, WotC released a new Primal Path for the babarian, the "Path of the Beast" which has the following rage feature:

Until the rage ends, you manifest a natural weapon. It counts as a simple melee weapon for you, and you add your Strength modifier to the attack and damage rolls when you attack with it, as normal. You choose the weapon’s form each time you rage:[…]

Claws. Each of your hands transforms into a claw, which you can use as a weapon if it’s empty. It deals 1d6 slashing damage on a hit. Once on each of your turns when you attack with a claw using the Attack action, you can make one additional claw attack as part of the same action.

Combined with 5 monk levels to get Extra attack and flurry of blows, could such a monk barbarian make 5 attacks in one round like:

1st round:

  • rage (bonus action)
  • 2 attacks (action) with claws
  • 1 extra claw attack (from "claws" feature)

2nd round:

  • 2 attacks (action) with claws
  • 1 extra claw attack (from "claws" feature)
  • 2 more attacks (bonus action flurry of blows)

Or am I missing a restriction that prevents this?

Is a car really sufficient cover from any grenade?

A flash-bang grenade is thrown in a parking lot. Somewhere else, in another identical parking lot, a fragmentation grenade is thrown. Can someone use a car as cover to completely avoid the effects of either explosion?

How does cover works in the case of a car used as cover? The rules say that a grenade doesn’t affect someone in cover unless it breaks the cover, and I cannot imagine the flash-bang grenade breaking the car — but at the same time, can the car really protect you from it? Similarly, I can’t imagine a car being fully destroyed by just a fragmentation grenade, so is it safe cover in that case?

Need Really Help !!!!

I am facing a weird problem. the URLs contain “%” in it, got broken once I post to the blogs.

After posting, if i click on the link, it says 404, I mean referring to a different page.

Any solution ??

How can I play a character like Chara from Undertale (with a really strong knife) in D&D?

In my friend’s D&D game, I am trying to find a way to play a character like Chara/Frisk, so the simplest way I thought I could do that is with an overpowered knife.

I was looking at Unearthed Arcana and I found the Psychic Warrior martial archetype for fighters (from UA: Fighter, Rogue, and Wizard), which was perfect, but then it got revised into the Psi Knight (in UA 2020: Psionic Options Revisited).

How can I create a character whose class allows them to make their melee weapons/attacks stronger, and who is able to do long-ranged energy slashes?

Of course, the former is more important than the latter.
I also don’t want paladin, rogue or ranger stuff. (The reason I don’t want rogue is because it’s more of a stealth class and I just want to kill people.)
I’m fine with Unearthed Arcana content; in fact, I would prefer it.

I’m not good at DMing, but I don’t think they really care… do I quit? [closed]

So I’ve been doing some thinking and essentially realized I’m a garbage DM. I am literally the embodiment of Railroading and unwillingness to listen to their wishes. I love my lore way too much and get major ideas of how I want things to go and struggle to give room.

Hard part is… they don’t really care that I do this. But what I mean is that maybe one of them is 100x better than me. In which case they should be doing it, not me! I mean I can see that there are definitely things they dislike about me. One guy in particular, I think, is spurred on a little by the Matt Mercer effect.

But I’m at a crossing, we are finishing a campaign I’m very disappointed in. The end became very clear and destined over time. They have started making their new characters and are getting excited to play my next story. But all I see is me failing them again. Do I take it into my hands and quit for their sake, or torture myself again as I realise I’ll never change and mess it up again?

Or am I just selfish by wanting to give up on them?

WireGuard / CVE-2019-14899: How secure the protocol really is?

I’ve been using OpenVPN and SSH tunnels for a multitude of scenarios over the years and recently I’ve been earning a lot of buzz around the simplicity and security of WireGuard. Now I’ve found some troubling information about CVE-2019-14899:

An attacker that controls your L2 link (i.e., your WiFi or LAN) can send specially crafted packets to your device. The attacker can then use those packets to actively probe for certain properties of the TCP connections originating from your device. In other words, by controlling a device’s access point to the Internet, an attacker can infer if the user is connected to a specific host and port.

Additionally, if a TCP connection is unencrypted inside the VPN tunnel (if you visit a page that uses HTTP instead of HTTPS, for instance), the attacker can inject packets into that specific unencrypted stream. This would allow an attacker to feed your device fake HTML content for that particular stream. That would be dangerous, but as previously stated, the attacker must target a specific TCP connection, so it is not a simple vulnerability to exploit.

Source: https://protonvpn.com/blog/statement-on-cve-2019-14899/

  1. Is this information technically correct?
  2. Some sources on the web also state that anyone controlling the WAN of the server will also be able to take advantage of this flaw. Is it true? Can the server’s ISP exploit this?

Assuming the information is correct:

  1. Why does it matter if the "TCP connection is unencrypted inside the VPN tunnel"? In theory one uses a VPN exactly to go around this issue – to make sure nobody can see the contents of the communication between two machines;
  2. If anyone controlling the client’s LAN can inject packages, how is this even considered a secure protocol? From my understating authenticity validation is a must in scenarios like this. The server should be able to check the authenticity of new data instead of blindingly accepting it… Isn’t there some kind of key exchange for this?
  3. According to Wireguard’s website "mimics the model of SSH and Mosh; both parties have each other’s public keys, and then they’re simply able to begin exchanging packets through the interface." How is a 3rd party (that doesn’t have the right keys) able impersonate the client, send data and then how the server decrypts it using the client’s real key without errors?

It look to me like the information about the CVE isn’t correct OR WireGuard was so badly designed that it can’t even use a proper key exchange to secure a communication channel.

Thank you in advance.

Destroying data on storage drives via overwrite methods really doesn’t work?

I’m going to sell a computer hard drive on the Internet, it’s a 500GB SATA hard drive, I really used it 3 or 2 years ago, I never used it again, I used about 20 or 40% of the space.

I have read about various tools and used Hardwipe, first I deleted the volume and recreated it, then with the program (option to clean free space) I used the GOST R 50739-95 method, when it finished then I did it again with the random method (both It took about 6 hours, in total I spent 2 days on this task, and I had several interruptions so I had to disconnect and continue the overwrite).

I have read an article on the internet (I shouldn’t believe everything I read on the internet, but that’s why I am asking this question), where it mentions that overwriting these random bytes is not enough and even if I used the DoD 5220.22-M method the data could To be recoverable, it mentions that a good method is degaussing (but this is really crazy, that is, a disk that used so little space), is this information really true? Should I use a Gutmann method?


Is there really no “Usenet” these days? Why has everything died out? [closed]

I got onto the Internet after the Eternal September of 1993. I thus never got to experience a time when there was some kind of minimal quality/intelligence in everything posted. Usenet has since at least the year 2000 been a useless ghost town filled with spam, if even that, and no ISP that I know of has been providing even one lousy Usenet server for the last 20+ years now.

It’s not just dead, but has long since been fully turned into dirt and forgotten.

I find that maybe 1/10 questions I ask on Stack Exchange get a useful answer from somebody who knows something, is interested to help, is able to help and actually did read my question. The other 90%, I just sit and waste my time carefully writing a question and jumping through all kinds of annoying hoops to get to finally post it, only to have it closed, deleted or downvoted into oblivion two microseconds after it’s been published. This happens over and over and over, with zero intention by me to do anything but genuinely ask real questions.

Even if Usenet would still exist, it’s no longer possible to register an e-mail account anonymously (no, that which you’re thinking of doesn’t work anymore), and it’s not even possible to pay (with Bitcoin). They all demand to fully track you. But either way, it doesn’t matter since Usenet is dead and I’m not talking about using e-mail anyway.

I’m talking about the idea of a decentralized (not fake-decentralized) network where you can exchange messages and not have to rely on and be terrorized by a central authority with "user accounts" which inevitably can only be registered by "IP addresses that we like" and "verified with SMS/photo id/blood sample".

I want to be able to fire away a JSON with a "title", "body" and "category" strings to somewhere, and then later get to "reap" replies to this message by similar means. No accounts or hoops. Spam would be handled by each user or by connecting to "hubs" that do such processing, for those who can’t or won’t do it themselves.

This would be great, but I’ve not seen anything like it even proposed. I feel utterly crippled and muffled. The only thing which exists now seems to be centralized nonsense services which are impossible to register an account on for anyone who cares to even a minimal extent about their privacy.

Why has everything died out? What’s stopping all these people who have infinitely more resources than I from actually launching such a thing and really promoting it to people like us at first? To get some kind of decentralized message system which doesn’t require mysterious and incomprehensible software and only has two people using it?

For starters, they could simply have a .php script hosted on some https:// URLs and have them exchange incoming messages with each other, as well as let anyone download the (recent) messages sent to them. Wouldn’t that be a super-simple and very doable network?

Why is this not a thing? Why do I have to rely on (fully) centralized services run by extremely dubious people? Why is there not even a theoretical chance of getting a message out into "cyberspace" anymore, through a system identical or similar to what I’ve just described?