Using server timestamp to synchronize actions across clients


tl;dr

The question is rather simple: how unsynchronized can internal clocks be between different machines?


Context

We have a "hybrid" approach where the Clients are authoritative on certain things, and the Server on some others. That is to make our life easier because the gameplay doesn’t need to be too tight about certain things.

In this case, the Server will pre-determine a sequence of Enemy Types to be spawned at different locations with pre-determined delay between the spawns. We would then let the Clients handle the rest during the gameplay.

However, if we want the Clients to be mostly synched on the display of the enemies, they would need to initiate this sequence at the very same time, and thus we cannot rely on the network to have transmitted the data at the very same time for all Clients.

The idea we had was to send a timestamp of the format returned by System.currentTimeMillis() which would indicate when to begin the sequence.

But then one question remains in the way: how unsynchronized can internal clocks be between different machines?

Google search console consider 404 urls as crawl anomaly category and not 404 not found category

I’ve got a site which we have mention as 404 not found for a few particular pages so that google can consider and push it to Excluded Not found (404) category, but still, google is considering those pages as crawl anomaly category. Please find the screenshot below.

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Acceptable background by level

Disclaimer: This has nothing to do with backgrounds from DND5.

It happens a lot that the story you create for your character sometimes is not as in point with what happens afterwards in-game. If you are a Lvl 1 Warrior you maybe can say you fought in the frontlines of a bloody war, and now are a retired mercenary.

Then you end-up losing to a bunch of rats the GM threw your way because the ceiling was too low and you forgot your matches.

What I want to know, is there a table/resource that has some indicator of what you may have accomplished when creating a character of a specific level?

That way I won’t embarrass myself narrating when I defeated a lich in my Lvl3 Ranger backstory, just to be inmediately destroyed by two goblins and their pet wolf in my first encounter.

I don’t mind DND/pathfinder responses, even when the power level may differ between the two, and even between versions, I’m more interested if the resource itself exists, or how to create one.

Why can’t I connect to the wordpress install page with Nginx?

I’m a newbie of WordPress. My environment is Ubuntu 18 + Nginx + PHP 7.

Following the tutorial(https://www.myfreax.com/how-to-install-wordpress-with-nginx-on-ubuntu-18-04/), the wordpress directory was placed on /var/www/html/device1.com.

Then I config the nginx, here is my nginx config:

server {     listen 80;     server_name www.device1.com device1.com;      server_name device1.com;      root /var/www/html/device1.com;     index index.php;       # log files     access_log /var/log/nginx/device1.com.access.log;     error_log /var/log/nginx/device1.com.error.log;      location = /favicon.ico {         log_not_found off;         access_log off;     }      location = /robots.txt {         allow all;         log_not_found off;         access_log off;     }      location / {         try_files $  uri $  uri/ /index.php?$  args;     }      location ~ \.php$   {         include snippets/fastcgi-php.conf;         fastcgi_pass unix:/run/php/php7.2-fpm.sock;     }      location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg)$   {         expires max;         log_not_found off;     }  } 

But, when I tried to connect to http://device1.com/wp-admin/install.php the Nginx responses 404, instead of returning the wordpress install page.

I don’t have any idea of checking the issue. Thanks for your suggestion.

Do I have to hold the Power Jewel to use it?

Power Jewel (Advendurers Vault, p176):

Power ♦ Daily (Minor Action)
This power allows you to regain the use of an encounter power of 1st or 3rd level.

Do I have to get it from my backpack before using it?

What about items that are normally1 used, like a Whistle of Warning2?


  1. Normally meaning their mundane versions have some applications, as opposed to a Power Jewel
  2. Adventurer’s Vault 2, page 78: Encounter(Minor) Each ally within 10 squares of you who can hear the whistle can shift 1 square and draw a weapon or retrieve an implement as a free action.

What properties of a discrete function make it a theoretically useful objective function?

A few things to get out of the way first: I’m not asking what properties the function must have such that a global optimum exists, we assume that the objective function has a (possibly non-unique) global optimum which could be theoretically found by an exhaustive search of the candidate space. I’m also using "theoretically useful" in a slightly misleading way because I really couldn’t understand how to phrase this question otherwise. A "theoretically useful cost function" the way I’m defining it is:

A function to which some theoretical optimisation algorithm can be applied such that the algorithm has a non-negligible chance of finding the global optimum in less time than exhaustive search

A few simplified, 1-dimensional examples of where this thought process came from: graph of a bimodal function exhibiting both a global and local maxima

Here’s a function which, while not being convex or differentiable (as it’s discrete), is easily optimisable (in terms of finding the global maximum) with an algorithm such as Simulated Annealing.

graph of a boolean function with 100 0 values and a single 1 value

Here is a function which clearly cannot be a useful cost function, as this would imply that the arbitrary search problem can be classically solved faster than exhaustive search.

graph of a function which takes random discrete values

Here is a function which I do not believe can be a useful cost function, as moving between points gives no meaningful information about the direction which must be moved in to find the global maximum.

The crux of my thinking so far is along the lines of "applying the cost function to points in the neighbourhood of a point must yield some information about the location of the global optimum". I attempted to formalise (in a perhaps convoluted manner) this as:

Consider the set $ D$ representing the search space of the problem and thus the domain of the function and the undirected graph $ G$ , where each element of $ D$ is assigned a node in $ G$ , and each node in $ G$ has edges which connect it to its neighbours in $ D$ . We then remove elements from $ D$ until the objective function has no non-global local optima over this domain and no plateaus exist (i.e. the value of the cost function at each point in the domain is different from the value of the cost function at each of its neighbours). Every time we remove an element $ e$ from $ D$ , we remove the corresponding node from the graph $ G$ and add edges which directly connect each neighbour of $ e$ to each other, thus they become each others’ new neighbours. The number of elements which remain in the domain after this process is applied is designated $ N$ . If $ N$ is a non-negligible proportion of $ \#(D)$ (i.e. significantly greater than the proportion of $ \#(\{$ possible global optima$ \})$ to $ \#(D)$ ) then the function is a useful objective function.

Whilst this works well for the function which definitely is useful and the definitely not useful boolean function, this process applied to the random function seems incorrect, as the number of elements that would lead to a function with no local optima IS a non-negligible proportion of the total domain.

Is my definition on the right track? Is this a well known question I just can’t figure out how to find the answer to? Does there exist some optimisation algorithm that would theoretically be able to find the optimum of a completely random function faster than exhaustive search, or is my assertion that it wouldn’t be able to correct?

In conclusion, what is different about the first function that makes it a good candidate for optimisation to any other functions which are not.

Is using stunting and pranks to gain advantage instead of stealth mechanically sound?

I would like to break the stereotype that rogues are always super stealthy sneaky types that appear from the shadows and strike and then disappear, for me that makes the flavor of the game not as fun and reduces the amount of decision making in-game. This is the reason I haven’t considered playing rogue ever.

I am selecting the thief rogue archetype in order to be able to take advantage of the use an object bonus action, and combine it with free actions for maximum effectiveness to allow for stunting and debuffing to gain the advantage required for sneak attacks. Is this a mechanically sound way to reliably trigger sneak attacks?

Ways this could potentially be implemented in practice:

  • Throwing dust into the eyes of an enemy
  • Using tinderbox to light their clothing, hair, or fur on fire
  • Using ten foot pole or quarter staff to poke and harass them
  • Using ropes and whips to attempt to trip them up or lasso them
  • Throwing caltrops, ball bearings, or oil, under their feet
  • Pantsing them or messing with their clothing in a similar way