Solve Matrix equations with Cross Product: weird system of equations

I would like to find the values {Pfx, Pfy, Pfz} that satisfy the equation A X B = C . The code of everything is at the end, I want to ilustrate with images what i think of first:

A is this:

Matrix A

B is this: {0,0,0}

And C is this: {100,500,200}

The image of the complete code is this one:

Complete code

My variable here are {Pfx,Pfy,Pfz} and the {i,j,k} are the unit vectors. The way that the matrix is shown in the picture corresponds with a trick used to solve in papper this type of matrix.

The solution would give me the value of Pfx in the "x" coordinate (and this would be expressed by Pfx being multiplied with the i vector). And the same mechanism applies with Pfy related with j Vector ; and Pfz related with k.

The problem here comes with the fact that the I can`t find the values {Pfx, Pfy, Pfz} that satisfy the equation A X B = C. I am not sure if the problem lies in the "LinearSolve" comand, in the use of the CrossProduct or in the use of the versor {i, j, k} inside the matrix.

Any kind of help in this regard will be extreamly useful, thanks in advance!!

Code:

i := {1, 0, 0}  j := {0, 1, 0}  k := {0, 0, 1}  LinearSolve[({ {i, j, k},{1, 2, 3},{Pfx, Pfy, Pfz}})\[Cross]({{0},{0},{0}}) == ( {{100},{500},{200}} )]    

Does Calm Emotions prevent the damage from Weird?

Weird says

On a failed save, a creature becomes frightened for the duration. The illusion calls on the creature’s deepest fears, manifesting its worst nightmares as an implacable threat. At the end of each of the frightened creature’s turns, it must succeed on a Wisdom saving throw or take 4d10 psychic damage. On a successful save, the spell ends for that creature.

Calm Emotions Says

You can suppress any effect causing a target to be charmed or frightened. When this spell ends, any suppressed effect resumes, provided that its duration has not expired in the meantime.

From this question, we’ve determined that calm emotions does not prevent saving throws against fear effects. This implies you would still make the saving throw against Weird. Does that mean that despite suppressing the effects of Weird, you might still take damage?

I’d like to know how people interpret the rules here, but also how you might rule it at your table. I’m inclined to think it’s silly to still take damage despite suppressing the fear, and would probably rule that you make the saving throw to end the effects of Weird, but if you fail you do not take damage.

Players playing weird characters breaking the immersion of my group

I have an issue with two players in my very large gaming group that I would like some advice from people who have perhaps dealt with players like these. In terms of age and experience, we’re all between the ages of 18 to 21, and we’ve variously been playing the game for 2 to 10 years. This particular instance there were only 4 players, but our extended group is near 20.

To put it simply, they will only play weird characters that break the immersion for my self and the other players. An example being a recent pathfinder game where the party consisted of a human gunslinger, human fighter, elf wizard, and a flail snail. It was a one of these things is not like the others situation. No one could really get into the game because of having to imagine this fairly typical group, plus a snail.

There was one instance where one of the players demanded to play an aquatic elf in a land locked campaign. It slowed the group down mechanically when they had to keep finding water. Another example is when the GM was adamant that the campaign he was running was human only, the player still went on to nag the GM to let him play anything from various pixies, plants, and even a swarm. The arguing wound up delaying the campaign from starting for several hours.

I’ve asked the players why they play these types of characters and they say things along the lines of:

  • Its too hard to play a humanoid character because there is too much to think about when playing a neurotypical standard humanoid
  • I want to play characters that no one can relate too
  • I like playing with self imposed restrictions in terms of how I act.

We have asked them as a group to play more normal characters and there have been mixed responses from the two. One will keep asking whoever is the DM until they break down and allow something. The other will play a more normal character but is clearly not having fun.

If anyone has had experience with a situation like this, how did you resolve it?

Weird looking ListDensityPlot graph

I am trying to use the following set of data to plot a 3D graph.

data = {{0.1`, -200, 2.47349`}, {0.1`, -180, 2.34881`}, {0.1`, -160,     2.215`}, {0.1`, -140, 2.08`}, {0.1`, -120, 1.93`}, {0.1`, -100,     1.84`}, {0.1`, -80, 1.69`}, {0.1`, -60, 1.53`}, {0.1`, -40,     1.46`}, {0.1`, -20, 1.19`}, {0.1`, 0, 1.62`}, {0.2`, -200,     2.46`}, {0.2`, -180, 2.163`}, {0.2`, -160, 1.95`}, {0.2`, -140,     1.73`}, {0.2`, -120, 1.52`}, {0.2`, -100, 1.36`}, {0.2`, -80,     1.12`}, {0.2`, -60, 0.9078`}, {0.2`, -40, 0.82`}, {0.2`, -20,     0.83`}, {0.2`, 0, 0.948`}, {0.3`, -200, 2.097`}, {0.3`, -180,     1.853`}, {0.3`, -160, 1.53`}, {0.3`, -140, 1.295`}, {0.3`, -120,     1.062`}, {0.3`, -100, 0.875`}, {0.3`, -80, 0.6164`}, {0.3`, -60,     0.4163`}, {0.3`, -40, 0.254`}, {0.3`, -20, 0.196`}, {0.3`, 0,     0.323`}, {0.4`, -200, 1.74`}, {0.4`, -180, 1.42`}, {0.4`, -160,     1.174`}, {0.4`, -140, 0.936`}, {0.4`, -120, 0.749`}, {0.4`, -100,     0.503`}, {0.4`, -80,     0.2565`}, {0.4`, -55, -0.0507`}, {0.4`, -35, -0.2962`}, {0.4`, \ -20, -0.264`}, {0.4`, 0, -0.133`}, {0.5`, -190, 1.3452`}, {0.5`, -170,     1.0393`}, {0.5`, -160, 0.92`}, {0.5`, -140, 0.736`}, {0.5`, -120,     0.45`}, {0.5`, -90,     0.1056`}, {0.5`, -70, -0.1159`}, {0.5`, -50, -0.32422`}, {0.5`, \ -40, -0.419`}, {0.5`, -20, -0.573`}, {0.5`, 0, -0.43`}, {0.6`, -200,     1.183`}, {0.6`, -180, 1.006`}, {0.6`, -170, 0.888`}, {0.6`, -150,     0.653`}, {0.6`, -130, 0.42`}, {0.6`, -100,     0.074`}, {0.6`, -80, -0.149`}, {0.6`, -50, -0.475`}, {0.6`, -40, \ -0.613`}, {0.6`, -10, -0.772`}, {0.6`, 0, -0.6`}, {0.7`, -200,     1.19`}, {0.7`, -165, 0.776`}, {0.7`, -160, 0.717`}, {0.7`, -130,     0.365`}, {0.7`, -110, 0.162`}, {0.7`, -100,     0.0176`}, {0.7`, -70, -0.315`}, {0.7`, -60, -0.432`}, {0.7`, -40, \ -0.672`}, {0.7`, -20, -0.8212`}, {0.7`, 0, -0.66`}, {0, -200,     1.937`}, {0, -180, 1.937`}, {0, -160, 1.937`}, {0, -140,     1.937`}, {0, -120, 1.937`}, {0, -100, 1.937`}, {0, -80,     1.937`}, {0, -60, 1.937`}, {0, -40, 1.937`}, {0, -20, 1.937`}, {0,     0, 1.937`}, {0.7855`, -200, 1.2206`}, {0.7855`, -170,     0.865`}, {0.7855`, -160, 0.745`}, {0.7855`, -140,     0.507`}, {0.7855`, -130, 0.388`}, {0.7855`, -110,     0.152`}, {0.7855`, -80, -0.195`}, {0.7855`, -50, -0.534`}, \ {0.7855`, -40, -0.666`}, {0.7855`, -10, -0.897`}, {0.7855`,     0, -0.609`}, {"", "", ""}, {0.15`, -180, 2.37`}, {"", "",     ""}, {0.15`, -140, 1.93433`}, {0.15`, -120, 1.7464`}, {0.15`, -100,     1.61726`}, {0.15`, -80, 1.41843`}, {"", "", ""}, {"", "",     ""}, {"", "", ""}, {0.15`, 0, 1.29525`}, {0.25`, -200,     2.20387`}, {"", "", ""}, {0.25`, -160, 1.73875`}, {"", "",     ""}, {0.25`, -120, 1.34535`}, {0.25`, -100, 1.10704`}, {0.25`, -80,     0.852466`}, {"", "", ""}, {0.25`, -40, 0.518832`}, {"", "",     ""}, {0.25`, 0, 0.616489`}, {0.05`, -200, 2.17447`}, {0.05`, -180,     2.15766`}, {"", "", ""}, {"", "", ""}, {"", "", ""}, {"", "",     ""}, {0.05`, -80, 1.8539`}, {0.05`, -60, 1.78145`}, {"", "",     ""}, {0.05`, -20, 1.771`}, {0.05`, 0, 1.85024`}}  

However, the final graph is weird (the mesh) enter image description here

It does not work when I increase the InterpolationOrder, and it does not work when I increase the number of data points. What is the problem here? Thank you so much.

Something weird going on with my algorithm?

I wrote an algorithm for data analysis using the CERN ROOT framework. It takes in three files of sorted UNIX timestamps from a single year, and pairs them up in the closest triplets, where each file contributes a triplet, and each triplet is unique. I know there are some more "well known" algorithms for accomplishing this, however this algorithm completes the task much faster, clocking in at about 20 minutes on my machine, as compared to many, many hours for some of the other algorithms I’ve tried. When complete, the algorithm plots the triplets (of the form {a,b,c]) on a 2-dimensional histogram, where the horizontal axis is a-b, and the vertical axis is a-c.

Problem is, it seems to be acting very weird. Namely, when I feed the algorithm one file of real data (these are timestamps generated by an experiment) and two files of completely random data, I get these weird diagonal lines: https://filebin.net/spbswnhkfy8xdkp8/random_plot.pdf?t=48f2yhjq. When I feed the algorithm three files of real data, a single diagonal line through the middle (and two more lines, running horizontally and vertically) appears if I use enough bins. Any idea what’s going on with my algorithm?

void unbiasedAnalysis(){  TNtupleD *D  = new TNtupleD("D","D","x:y");  ROOT::RDataFrame statn1("D", "./pathtodata"); ROOT::RDataFrame statn2("D", "./pathtodata"); ROOT::RDataFrame statn3("D", "./pathtodata");  vector<double> vec_1, vec_2, vec_3; statn1.Foreach([&](double tstamp){ vec_1.push_back(tstamp); },{"UNIX"}); statn2.Foreach([&](double tstamp){ vec_2.push_back(tstamp); },{"UNIX"}); statn3.Foreach([&](double tstamp){ vec_3.push_back(tstamp); },{"UNIX"});  vector<vector<double>> pairs; for(auto tstamp : vec_1){      double first,second;      //get iterator pointing to closest element greater than or equal to     auto geq = std::lower_bound(vec_2.begin(), vec_2.end(), tstamp);     //get iterator pointing to nearest element less than     auto leq = geq - 1;      double foo = tstamp - *geq;     double bar = tstamp - *leq;      //compare iterators, save the closest      if(dabs(foo) <  dabs(bar)){ first = *geq; }     else { first = *leq; }         //repeat     geq = std::lower_bound(vec_3.begin(), vec_3.end(), tstamp);     leq = geq - 1;      foo = tstamp - *geq;     bar = tstamp - *leq;      if(dabs(foo) < dabs(bar)){ second = *geq; }     else { second = *leq; }      //add to pairs     pairs.push_back({tstamp, first, second, (tstamp-first), (tstamp-second), std::min((tstamp-first), (tstamp-second))});  }  //sort vector of vectors by size of smallest difference std::sort(pairs.begin(), pairs.end(),     [](const vector<double>& A, const vector<double>& B){         return A[5] < B[5]; });  std::set<double> cache;  ROOT::EnableImplicitMT();  for(auto pair : pairs){     //if not in cache, add to TNtuple     if(cache.find(pair[1]) == cache.end() && cache.find(pair[2]) == cache.end()){              D->Fill(pair[3],pair[4]);          //add to cache         cache.insert(pair[1]); cache.insert(pair[2]);     } }  D->Draw("x:y>>htemp(100,-0.02,0.02,100,-0.02,0.02)","","colz"); 

}

Weird normal graph, what’s happening?

This appears to be a very basic question for this Stack Exchange, but hopefully still welcome. I am a math teacher and wanted to write a program to demonstrate normal distributions. I wrote a simple code in Processing that essentially flips a coin a certain number of times and makes a histogram of the results:

int piles = 200; int[] amounts = new int[piles]; int counter = 0; int maximum = 2000; void setup(){   size(1000,1000);   for(int i=0;i<piles;i++){     amounts[i] = 0;   } }  void draw(){   if(counter < maximum){     int value = 0;     for(int i=0;i<piles;i++){       if((int)random(0,2) == 0){         value++;       }     }     amounts[value]++;     for(int i=0;i<piles;i++){       for(int k=0;k<amounts[i];k++){         ellipse((1000*i+500)/piles,(1000*k+500)/piles,1000/piles,1000/piles);       }     }     counter++;   } } 

The strange thing is that the histogram always ends up being very "pointy". Does this happen because of the random() method, are normal distributions pointier than I thought, or am I missing something stupid?

https://i.stack.imgur.com/DZGqu.png

Weird GET request on internet facing Nginx

I spun up an internet facing nginx server in AWS and the logs started showing weird get requests with a search engine’s spider as user agent.

172.31.43.193 - - [19/Aug/2020:20:09:19 +0000] "GET /rexcategory?categoryCodes=SHPCAT33&t=1360657001168 HTTP/1.1" 404 153 "-" "Sogou web spider/4.0(+http://www.sogou.com/docs/help/webmasters.htm#07)" "49.7.20.159"  2020/08/19 20:08:39 [error] 29#29: *14 open() "/usr/share/nginx/html/eyloyrewards/category" failed (2: No such file or directory), client: 172.31.43.193, server: localhost, request: "GET /eyloyrewards/category?categoryCode=SHPCAT118&t=1314948609334 HTTP/1.1", host: "www.rewards.etihadguest.com"  172.31.43.193 - - [19/Aug/2020:20:08:39 +0000] "GET /eyloyrewards/category?categoryCode=SHPCAT118&t=1314948609334 HTTP/1.1" 404 153 "-" "Sogou web spider/4.0(+http://www.sogou.com/docs/help/webmasters.htm#07)" "49.7.20.159" 

The domain mentioned in the second line does not belong to me. What is the meaning of these logs? Is my server being used to attack the mentioned domain, "www.rewards.etihadguest.com" ?

Weird phone call [closed]

about a year ago I got a phone call from Africa and when i picked up i could hear weird music in the back, they played in different orders and it just sounded weird it was terrible like they didn’t know how to play. I said hello with no respond back so i hung up. Yesterday i got a weird phone call again but i didn’t pick up. they called a few times and then decided to text me saying that i had to pick up ASAP and that there’s a party. He called me babe like we were dating. Today they decided to keep calling so i picked up and the call was from Sweden (where i live) again no answer so i said hello but no one answered so i hung up.

i’m really confused about what is going on and if somebody have heard of something like this before?

MySQL InnoDB Weird Query Performance

I designed two tables, both using InnoDB. The first one has columns “Offset, Size, and ColumnToBeIndexed” with BIGINT “Offset” being the primary key, and the second one has columns “OffsetAndSize, and ColumnToBeIndexed” with BIGINT “OffsetAndSize” being the primary key. And there are both 15 millions rows in each table. I added indexes to both tables on “ColumnToBeIndexed.”My two queries for them are “SELECT Offset, Size FROM someTable WHERE ColumnToBeIndex BETWEEN 20 AND 10000 ORDER BY Offset ASC” and “SELECT OffsetAndSize FROM someTable WHERE ColumnToBeIndex BETWEEN 20 AND 10000 ORDER BY OffsetAndSize ASC.” Because the second query could use the secondary index and does not need to look up the clustered index to find the “size” information, I expected that the second query on the second table performs better than the first query on the first table. However, as the test came out, it turned out that the first query performs better every single time. Does anybody out there know what seems to be the problem?

I have this character idea but the magic is weird with it and I can’t figure it out [closed]

I am very new to D&D 5e. The whole idea behind the character is that they can manipulate metal decently almost telekeneticaly, like throw a knife and control it in the air or tangle the bad guy up with some chains. Only issue is that I can’t figure out how the magic system works nor can I figure out how to do this with a charcter. Is there something specific like an item to make this work or should I scrap the idea?