$\frac{5}{3\cdot2!}+\frac{5\cdot7}{3^2\cdot3!}+\frac{5\cdot7\cdot9}{3^3\cdot4!}+\space...\space=\space?$
Summing a series having a geometric component
Is it possible to include the tag-wiki associations in the Data Explorer? To do this would require two additional columns in the postTags table that associate a tag wiki excerpt and a tag wiki to their tag.  The tag wiki data is already available in the posts table. But there is no way to associate this data with its tags. The SEDE schema lacks the required columns to link the tag excerpt and the tag wiki to the tags table.  Additionally, the postTypes table only lists three posts types. It makes no mention of tag-wiki and tag excerpt posts. Perhaps the postypes table can be updated to reflect the additional post types? NEWID() In Joined Virtual Table Causes Unintended Cross Apply Behavior My actual work query was an inner join, but this simple example with cross join seems to nearly always reproduce the problem.  SELECT * FROM (     SELECT 1 UNION ALL     SELECT 2 ) AA ( A ) CROSS JOIN (     SELECT NEWID() TEST_ID ) BB ( B )   With my inner join I had many rows for which I added to each a GUID using the NEWID() function, and for about 9 out of 10 such rows the multiplication with the 2-row virtual table produced the expected results, just 2 copies of the same GUID, while 1 out of 10 would produce different results. This was unexpected to say the least and gave me a really hard time trying to find this bug in my test data generation script.  If you take a look at the following queries using as well non-deterministic getdate and sysdatetime functions, you won't see this, I don't anyway-I always see the same datetime value in both final result rows.  SELECT * FROM (     SELECT 1 UNION ALL     SELECT 2 ) AA ( A ) CROSS JOIN (     SELECT GETDATE() TEST_ID ) BB ( B )  SELECT * FROM (     SELECT 1 UNION ALL     SELECT 2 ) AA ( A ) CROSS JOIN (     SELECT SYSDATETIME() TEST_ID ) BB ( B )   I'm currently using SQL Server 2008 and my work around for now is to load my rows with GUIDs into a table variable before finishing out my random data generation script. Once I have them as values in a table as opposed to virtual table, the problem goes away.  I have a workaround, but I'm looking for the ways to workaround without actual tables or table variables.  While writing this I tried without success these possibilities: 1) placing the newid() into a nested virtual table:  SELECT * FROM (     SELECT 1 UNION ALL     SELECT 2 ) AA ( A ) CROSS JOIN (     SELECT TEST_ID     FROM (         SELECT NEWID() TEST_ID     ) TT ) BB ( B )   2) wrapping the newid() within a cast expression such as:  SELECT CAST(NEWID() AS VARCHAR(100)) TEST_ID   3) reversing the order of appearance of the virtual tables within the join expression  SELECT * FROM (     SELECT NEWID() TEST_ID ) BB ( B ) CROSS JOIN (     SELECT 1 UNION ALL     SELECT 2 ) AA ( A )   4) using uncorrelated cross apply  SELECT * FROM (     SELECT NEWID() TEST_ID ) BB ( B ) CROSS APPLY (     SELECT 1 UNION ALL     SELECT 2 ) AA ( A )   Just before finally posting this question, now I tried this with success it seems, a correlated cross apply:  SELECT * FROM (     SELECT NEWID() TEST_ID ) BB ( B ) CROSS APPLY (     SELECT A     FROM (         SELECT 1 UNION ALL         SELECT 2     ) TT ( A )     WHERE BB.B IS NOT NULL ) AA ( A )   Anyone have any other more elegant, simpler workaround? I really don't want to use cross apply or correlation for a simple row multiplication if I don't have to. Parallel option performing worse on cluster I'm trying out oracles parallel option on a cluster and surprisingly I am getting worse results with the parallel option. I was expecting some improvement with the parallel option but certainly not worse results. I am wondering why this is the case, and if there is anything wrong with the way I am using the parallel option on my cluster.   I am using a degree of 4 when the number of CPU's I have is 8. I have tried adding parallel to the cluster directly ALTER CLUSTER cluster PARALLEL 4 as well as at the statement on both the index /*+ PARALLEL_INDEX(clust_index, 4) */and tables /*+ PARALLEL(4) */,   Here is my trace from the parallel:    Without parallel: Where can the last FSTrim be seen as successful or not? (log files) I recently installed an SSD and AFAIK Ubuntu makes a weekly FSTrim on SSD's that support it.  Is there a log file of this trims? Extracting usernames from the /etc/passwd file How many arguments does a function require, and how to use that in `Manipulate` Questions in titles need to be repeated, why?  To me this pattern seems ridiculous. But I frequently encounter the "not a real question" situation, when I put my question in the title, then the context for that specific question in the 'question body'.     So:  I am to take it that the title is almost completely irrelevant for establishing subsequent question body is asking? I choose my titles to expose the actual question so it need not be repeated below. If questions need to be repeated in the body, could we simply title it "A question, click here and read below" ?   Tagged bug, as I have found this "problem" to be quite reproducible.  Steps to reproduce:   Ask a question with the clear, simple question in the title, and the evidence/context/example in the question body. Await close votes. I've just installed MariaDb on a fresh Ubuntu Gnome and ran  afterwards where I set a decent admin password, removed the anonymous user etc.  Afterwards I realized some strange behavior regarding the admin password:   If I try to login from my normal user account using the command mysql -u root -p I always get an error: ERROR 1698 (28000): Access denied for user 'root'@'localhost' I'm pretty sure I entered the correct password which I set with  earlier... When I run the command from root using sudo mysql -u root -p, I always get access to the database, no matter which password I actually enter...   Is this normal behavior, am I doing anything wrong or have I somehow screwed up the installation? Mismatch Reputation in the thumbnail and the actual Reputation How do you determine what technology a website is built on? Quite often I come across a nice looking or functional website, and wonder what technology was used to create it. What techniques are available to figure out what a particular website was built with?  Few frameworks seem to include any kind of generator meta tag like web editors do. Are there any tell-tale signs of particular languages and/or frameworks?    Summary of answers  Site URLs may betray the framework and/or programming language but cannot be relied upon (e.g. file extensions such as .asp). HTTP response headers, cookies, stylesheets and source comments may also give clues.  Some nice tools for querying site details (no doubt there are many more):          Firefox addons:    - CMS, frameworks/libraries, e-commerce, message boards etc.  - IP, country and webserver details  - Javascript libraries in use   Chrome Extensions:        Bookmarklets:    - shows Javascript framework in use Setting PATH variable in /etc/environment vs .profile Where is the preferred place to set the PATH envvar?  ~/.profile or /etc/environment?  What is the case when PATH is set in both places? Is the end result a concatenation of both values set in those two places? How to create a label combining different font sizes or types? I would like to place the elevation-number of a point in a different front size and centred under its name:    Is that possible?  (That is my actual labeling: label || '\n' || elevation) On a series involving harmonic numbers Vectors, structs and std::find I navigate with Ctrl-n,p,f,b (readline/ keys), so that I don't have to move my hands too much and get  again. Is there a way to disable Ctrl-b being hotkey for bold?  Note that this is not just an Emacs thing. Standard web browsers, like Firefox and Chrome, use things like  Ctrl + K and Ctrl + L to navigate to the Google search bar and address bar respectively. This post is in reference to the following blog post:   To start off, a quick introduction of myself; my name is Jascha Drel, Product Manager for Advertising at Stack Overflow. In this role, I am part of ’s organization.   Our team is continuously making improvements to the ads experience on our sites. One of the changes we’re excited about sharing is the new Report this Ad feature now available on some of our sites. We want to continue to give our communities more native control over their ad experience. We needed a quantifiable way to receive feedback and this feature will allow that.  We enforce strict  on the types of advertisers we work with but cannot fully control what is shown due to how advertising delivery works. However, being able to hear from our users about problematic ads will be a huge benefit as we can address those problems faster and with more accuracy. The Report this Ad feature will allow us to quickly see and investigate ads reported by you which matters to us because we want to hear your thoughts.  Furthermore, this new feature ensures that the members of our communities have a built-in way to report ads they consider problematic when we test any new ad formats/solutions.  We are launching this feature on 5 sites initially (, , , , and ) to get a good understanding of what we can expect in terms of numbers of reports whenever launching this to the entire network. Prior to launching it network-wide, we’ll share general results we’ve seen here.  What happens once an ad is reported?  All reports will be consolidated into a dashboard that the team will look at several times per week to spot irregularities in terms of the total number of reports, report categories, and on an advertising campaign basis. We will not be replying to individual reports, but we will reach out to our advertisers, to share feedback or notify them if the ad being reported does not fit our guidelines. We may also evaluate our policies in response to large numbers of reports not covered by them. Since we don’t have a baseline for the number of ads that are going to be reported using this new feature, we will consider reevaluating the process if the current process doesn’t scale.    We’d like to share an update on the progress of this feature:   We've launched this feature on 5 SE sites (Server Fault, Database Administrators, Arqade, Game Development, and Unix &amp; Linux) initially for logged in users only, and for anonymous users afterward. The report this ad button was shown several million times (of which roughly 65% paid ads and 35% house ads). We showed several dozens of different ad campaigns. So far we have received 0 reports. We've tested the feature several ways, found some minor bugs (which have been/are being fixed), however, in the vast majority of the scenarios the feature works well (we’re happy to be ).   We’re currently graduating this feature and are releasing it network-wide this week. Feel free to comment below if you have any questions/comments. SSH connection problem with "Host key verification failed..." error I can connect to another Ubuntu machine in my LAN via SSH. On both of then PC's I installed   but from another Ubuntu computer I can not connect to my PC via SSH and I got this error:     Host key verification failed... I'm trying to split text in a JTextArea using a regex to split the String by \n However, this does not work and I also tried by \r\n|\r|n and many other combination of regexes. Code:  public void insertUpdate(DocumentEvent e) {     String split[], docStr = null;     Document textAreaDoc = (Document)e.getDocument();      try {         docStr = textAreaDoc.getText(textAreaDoc.getStartPosition().getOffset(), textAreaDoc.getEndPosition().getOffset());     } catch (BadLocationException e1) {         // TODO Auto-generated catch block         e1.printStackTrace();     }      split = docStr.split("\\n"); } I need to set weights for some edges from a python script. I have tried looping through object.data.edges and setting bevel_weight values but I can't get it right. It only works if I have first edited some edge's bevel weight by hand from the 3d-view's transform window. But I would like to get it work from my script without any manual hacking.  Steps to reproduce:  Start Blender with default cube and switch to Scripting view.  Try to set weights for all edges:  for edge in C.object.data.edges:     edge.bevel_weight = 1.0   Verify that values changed:  for edge in C.object.data.edges:     edge.bevel_weight   Switch into edit mode in 3d-view and open up transform window by pressing n. Select edges to see that the change did not work (bevel weights are all zero). Switch back to object mode and read values again in scripting console to see that they were reset to zero:  for edge in C.object.data.edges:     edge.bevel_weight   Go back to edit mode and change some edge bevel weight straight from the transform window by hand. Go back to object mode and change values again from the scripting console:  for edge in C.object.data.edges:     edge.bevel_weight = 1.0   This time it works, bevel weights are 1.0 when you go back to edit mode and look from the transform window.   Any ideas? My final need is to apply a bevel modifier to only some set of edges and that's why I'm trying to mark them by using weights. Using vertex group for bevel modifier does not work in my situation, since I need to specify edges, not vertices, which to bevel.   I'm using Blender v2.71. Seeing as C# can't switch on a Type (which I gather wasn't added as a special case because is relationships mean that more than one distinct case might apply), is there a better way to simulate switching on type other than this?  void Foo(object o) {     if (o is A)     {         ((A)o).Hop();     }     else if (o is B)     {         ((B)o).Skip();     }     else     {         throw new ArgumentException("Unexpected type: " + o.GetType());     } }