I am trying to setup build environment on  Ubuntu 12.04 (precise)(64bit). I am following the guide at . I encountered the following message.  $ sudo apt-get install  libgl1-mesa-dev [sudo] password for buddy:  Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  libgl1-mesa-dev : Depends: mesa-common-dev (= 9.2.0~git20131002+9.2.2eb55601-0ubuntu0sarvatt~precise)                    Depends: libdrm-dev (&gt;= 2.4.45) E: Unable to correct problems, you have held broken packages.   I tried installing mesa-common-dev  $ sudo apt-get install  mesa-common-dev   message  The following packages have unmet dependencies:  mesa-common-dev : Depends: libdrm-dev (&gt;= 2.4.45)   Then I tried installing   $ sudo apt-get install libdrm-dev   message  The following packages have unmet dependencies:  libdrm-dev : Depends: libdrm2 (= 2.4.46-1ubuntu0.0.0.1) but 2.4.46+git20130702.c6d73cfe-0ubuntu0sarvatt~precise is to be installed               Depends: libdrm-intel1 (= 2.4.46-1ubuntu0.0.0.1) but 2.4.46+git20130702.c6d73cfe-0ubuntu0sarvatt~precise is to be installed               Depends: libdrm-radeon1 (= 2.4.46-1ubuntu0.0.0.1) but 2.4.46+git20130702.c6d73cfe-0ubuntu0sarvatt~precise is to be installed               Depends: libdrm-nouveau1a (= 2.4.46-1ubuntu0.0.0.1) but 2.4.46+git20130702.c6d73cfe-0ubuntu0sarvatt~precise is to be installed               Depends: libdrm-nouveau2 (= 2.4.46-1ubuntu0.0.0.1) but 2.4.46+git20130702.c6d73cfe-0ubuntu0sarvatt~precise is to be installed               Depends: libkms1 (= 2.4.46-1ubuntu0.0.0.1) but 2.4.46+git20130702.c6d73cfe-0ubuntu0sarvatt~precise is to be installed E: Unable to correct problems, you have held broken packages.   Then I tried the following steps mentioned here:  skipping the Disable/Remove/Purge PPAs part.
Occasionally, when I'm installing stuff, I get an error like the following:  Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  package1 : Depends: package2 (&gt;= 1.8) but 1.7.5-1ubuntu1 is to be installed E: Unable to correct problems, you have held broken packages.   How can I resolve this?
This should be a very easy question but it might just be that I'm confusing myself. So we have the definition of a function $f$ on $S$ being continuous at $x_0$:     For any $\epsilon$>0, there exists $\delta&gt;0$ such that: whenever $|x-x_0|&lt;\delta$, we have $|f(x)-f(x_0)|&lt;\epsilon$   And I assume the negation is     There exists $\epsilon$>0 such that for all $\delta&gt;0$, $|x-x_0|&lt;\delta$ yet $|f(x)-f(x_0)|\ge \epsilon$.   Now I want to show that the function $f(x)=\sin(\frac{1}{x})$ together with $f(0)=0$ cannot be made into a continuous function at $x=0$. So I need to show that there exists $\epsilon&gt;0$ such that for all $\delta&gt;0$, $|x|&lt;\delta$ yet $|f(x)|\ge\epsilon$.  Let $\epsilon = \frac{1}{2}$. Then no matter what $\delta$ we choose, let $|x|&lt;\frac{1}{2}$. It is certainly possible that $|f(x)|\ge \frac{1}{2}$, because, well, $\frac{1}{x}$ can really take on arbitrarily large value as $x$ is small.  Now, what confuses me is that, as $x$ gets small, $f(x)$ can certainly be greater than $\frac{1}{2}$ for infinitely many times, but it will be less than that infinitely many times, too. But I suppose it doesn't really matter. So I think there's something wrong with my negation but I couldn't figure out where.  Update: The correct version can be found . Watch for Lemma 4.6 Looking for a short story about an insect-like alien captured by humans on its own planet This poor creature is taken aboard the spaceship and the humans do not know that it is intelligent.  The alien can repeat what it hears, e,g, "pass the sugar".  It is able to escape at night and it communicates messages to its fellow aliens.  It directs that they turn up the heat of the atmosphere (somehow they can do this) so as to force the humans to leave.  The alien protagonist states that it will die w/ the humans or leave with them. What is a deterministic method for evaluating a sensible buffer pool size? I'm trying to come up with a sane way to understand if the max server memory (mb) setting is appropriate (either should be lower, or higher, or stay the way it is).  I am aware that max server memory (mb) should always be low enough to leave room for the operating system itself, etc.    The environment I'm looking at has several hundred servers; I need a reliable formula I can use to determine if the present size of the buffer pool is appropriate since RAM is costed per GB allocated to each server.  The entire environment is virtualized, and "physical" RAM allocated to a VM can easily be changed up or down.  I have a particular SQL Server Instance I'm looking at now with a PLE of 1,100,052 seconds, which equates to 12.7 days (the amount of time the server has been up).  The server has a max server memory setting of 2560MB (2.5GB), of which only 1380MB (1.3GB) is actually committed.    I've read several items including one by Jonathan Keheyias () and another by Paul Randal (), and several others.  Jonathan advocates monitoring for a PLE below 300 per 4GB of buffer pool as being too low.  For the SQL Server Instance above, 300 * (2.5 / 4) = 187 results in a really really low target PLE below 300.  This instance has 290GB of SQL Server data (not including log files), and is only used for integration testing.  Assuming the last 12 days is representative of typical usage for this server, I'd say the max server memory (mb) setting could be lowered.  At the other end of the scale, I have another integration-test server with a PLE of 294, that has a max server memory (mb) setting of only 1GB.  This server has only 224MB of SQL Server data not including logs, and is running some BizFlow databases.  This server might benefit from a higher max server memory (mb) setting.  I'm thinking a good starting place for targets that might be assigned too much memory could include looking at:  SELECT      RamMB = physical_memory_in_bytes / 1048576     , BufferPoolCommittedMB = bpool_committed * 8192E0 / 1048576     , BufferPoolCommitTargetMB = bpool_commit_target * 8192E0 / 1048576     , PercentOfDesiredSizeMB = CONVERT(INT,(CONVERT(DECIMAL(18,2),bpool_committed)                              / bpool_commit_target) * 100) FROM sys.dm_os_sys_info;   If BufferPoolCommitTargetMB / BufferPoolCommittedMB is greater than 1, the server is not using the entire buffer pool.  If the machine in question also has a PLE of greater than "x" then it might be a good candidate for a decrease in max server memory (mb).  Since the Buffer Manager:Lazy writes/sec performance counter tracks the number of times SQLOS has written pages out to disk between checkpoints due to memory pressure, this might be another good thing to look at.  DECLARE @WaitTime DATETIME; SET @WaitTime = '00:00:15'; DECLARE @NumSeconds INT; SET @NumSeconds = DATEDIFF(SECOND, 0, @WaitTime); DECLARE @LazyWrites1 BIGINT; DECLARE @LazyWrites2 BIGINT;  SELECT @LazyWrites1 = cntr_value  FROM sys.dm_os_performance_counters dopc WHERE (         dopc.counter_name LIKE 'Lazy writes/sec%' COLLATE SQL_Latin1_General_CP1_CI_AS     )     AND dopc.object_name = 'MSSQL$' + CONVERT(VARCHAR(255),                SERVERPROPERTY('InstanceName')) + ':Buffer Manager';  WAITFOR DELAY @WaitTime;  SELECT @LazyWrites2 = cntr_value  FROM sys.dm_os_performance_counters dopc WHERE (         dopc.counter_name LIKE 'Lazy writes/sec%' COLLATE SQL_Latin1_General_CP1_CI_AS     )     AND dopc.object_name = 'MSSQL$' + CONVERT(VARCHAR(255),                SERVERPROPERTY('InstanceName')) + ':Buffer Manager';  SELECT LazyWritesPerSecond = (@LazyWrites2 - @LazyWrites1) / @NumSeconds;   The above code assumes the server is under load during the 15 seconds it takes to run, otherwise it will report 0; which might be a misleading false-negative.  Should I also look at PAGELATCHIO_* wait stats or some other wait type as an indicator of memory pressure, or lack thereof?   My question is, how can I reliably determine a "good" target value for PLE and max server memory (mb)? I am developing a game with a Minecraft-like terrain made out of blocks. Since basic rendering and chunk loading is done now, I want to implement block selecting.  Therefore I need to find out what block the first person camera is facing. I already heard of unprojecting the whole scene but I decided against that because it sounds hacky and isn't accurate. Maybe I could somehow cast a ray in view direction but I do not know how to check the collision with a block in my voxel data. Of course this calculations must be done on the CPU since I need the results to perform game logic operations.  So how could I find out which block is in front of the camera? If it is preferable, how could I cast a ray and check collisions? While accepting an offer to grad school, one is basically entering into a lasting relationship with one's adviser - most likely, someone whom the applicant has never met before, and the only exposure has been through the potential adviser's website/publications. It is in the interest of both parties to ensure (to the greatest possible extent) that there are no personal/professional traits of either that hamper the formation of a pleasant working relationship - no-one would want to go through the ordeal of having to change advisers midway!  While the faculty has a chance to have a good look at the applicant's profile as well as his motivations (through his grades and SOP), the applicant doesn't have a similar opportunity. So, I'm interested to know what parameters can be used to gauge a potential fit. I've thought of the following:   Past students:  Did anyone ever drop out/change advisers midway, and if so, for what reasons? These would be a bit hard to find though, as I don't expect the faculty concerned would list them on their website. It would be great if anyone could let me know how to find out the list of incoming students to a department for any year. Publication rate, taking into account the venues where they were accepted. Time taken to graduate - though I accept this is more dependent on the student, a median figure should be telling ... What they did post Ph.D. - did anyone get tenure if they went into academia, or is almost everyone unable to break out of being a post-doc?  Tenure status: I'm a bit unsure about this, so wanted the community's opinions about it. Just so that I'm clear, I'm only trying to calibrate the applicant's expectations about the working style of his potential adviser - and hence need to know to what extent are the following "typical" assumptions valid.  Tenured professor  A full professor is more likely to get grant funding, hence less time spent on TAship - but could also mean less time/effort spent on interactions with students (either being busy with other projects/talks, or due to more commitments to family at that age).  Tenure-track faculty (Assistant profs)  More likely to be young and energetic, and could translate to more time spent on one-to-one discussions with grad students - but funding may prove to be an issue, and may have to be on TA for a longer period.   What other factors would be relevant in this matter, and to what extent am I correct/incorrect in either the factors considered, or for undertaking this exercise at all? I'm trying to remember a cartoon tv show where the main boy, a blonde girl, and another boy capture monsters. There was something about a 'veil' between their world and the monster world, but a 'secret society' of sorts stopped the monsters from crossing, or used them to battle the people who wanted to use them for evil led by a wise old lady. I'm pretty sure they trapped monsters into pieces of jewelry or clothing.   Not so sure about this part: and they had these 'supernatural powers' that were connected to their 'aura' and they could travel from place to place with it.   (Another brown haired girl joined because she found out? There was an arc where the blonde got jealous and the monster she controlled attacked the brown haired girl?)  I can't remember much of it, but I remember in the end the 'veil' was broken and monsters flew over the city. And the main boy and the blonde girl held hands... or kissed? How to install a deb file, by dpkg -i or by apt? Can bounties be awarded multiple times by the same person on the same question? Is there any restriction to prevent multiple bounties ( not simultaneously) being awarded to different answers on the same question ?  i.e., on a question  -  I want to set multiple bounties since I've received 2 awesome answers. Can I set award a bounty on answer A first, and then set the bounty and award it to answer B ? how to redirect output to multiple log files How to avoid using sudo when working in /var/www? I want to stop having to use sudo everytime I work in /var/www. How can I do that? I simply want to put all of my sites into this directory and work with them without too much pain. 9 rows is just way too small by default. Is this a text-editor for ants? How do I check the integrity of a storage medium (hard disk or flash drive)? Suppose that G is a group and N &lt; G a normal subgroup. Assume that there is no normal subgroup M &lt; G with N &lt; M. Prove that G/N is simple.  This problem is really throwing me for a loop. The concept of quotient groups and how they relate to simple subgroups is confusing me, and so I am not really sure how to begin. If a simple subgroup's only normal subgroup is itself (and the trivial group), then G/N being simple would be proving that when multiplying the entire subgroup N by an element g for all g in G, that the collection of those sets cannot be broken into smaller normal subgroups? How do I import a Python module given its relative path?  For example, if dirFoo contains Foo.py and dirBar, and dirBar contains Bar.py, how do I import Bar.py into Foo.py?  Here's a visual representation:  dirFoo\     Foo.py     dirBar\         Bar.py   Foo wishes to include Bar, but restructuring the folder hierarchy is not an option. Prove or disprove: $S_{10} = \langle (1,3),(1,2, ... ,10) \rangle$ Question:   Answer:   The question was closed at 11:57:57 (according to the hover-over-"x-mins-ago" bar) and the answer was posted at 12:16:35. It's a fairly lengthy answer, so it's possible that it was started to be written before it was closed but I swear I've started to answer a question then I got a banner along the top saying "this question has been closed" and the answer was no longer post-able. Custom counter steps twice when invoked from caption using caption package Mathematical Prerequisites for QFT How would Voldemort restore himself from a horcrux? If Voldemort's body dies, what process would he use to restore himself from a horcrux? His plans seem sloppy for the pains he had taken. For example, why create horcruxes from pieces of jewellery when they dont have the agency to seek out a new body by themselves?  He needed Quirrel, a person with unlikely ambitions to seek him out to gain an useful body. When that body was gone, he needed Barty Crouch, someone with questionable agency (he could be imprisoned) to transport Harry and draw his blood.  Nagini and the diary seems the only horcruxes with agency, the others are mostly inert.  What plans were ever taken to restore Voldemort from his horcruxes? get current user info using jquery ,REST and csom My goal is to get the login name and picture for the current user. I am using SharePoint 2013 Foundation. I tried three method and non of then worked correctly:   This is with jQuery SPServices:   function getCurrentUserInfo() {     var thisUsersValues = $().SPServices.SPGetCurrentUser({         fieldNames: ["ID", "Name", "Picture"],         debug: false     });      var name = thisUsersValues["Name"];      var ID = thisUsersValues["ID"];      var SIPAddress = thisUsersValues["Picture"];  }    But I am getting this error:     SCRIPT438: Object doesn't support property or method 'replace'      File: jquery.SPServices-2014.01.js, Line: 2414, Column: 17    REST API method:   function getinfo(loginName) {     var theData = {         "propertiesForUser": {             "__metadata": { "type": "SP.UserProfiles.UserProfilePropertiesForUser" },             "accountName": loginName,             "propertyNames": ["PreferredName", "PictureURL"]         }     };      var requestHeaders = {         "Accept": "application/json;odata=verbose",         "X-RequestDigest": jQuery("#__REQUESTDIGEST").val()     };      jQuery.ajax({         url: _spPageContextInfo.webAbsoluteUrl + "/_api/SP.UserProfiles.PeopleManager/GetUserProfilePropertiesFor",         type: "POST",         data: JSON.stringify(theData),         contentType: "application/json;odata=verbose",         headers: requestHeaders,         success: function (data) {             document.getElementById("profilelink").href = userProfileProperties[1];;             document.getElementById("username").innerHTML = userProfileProperties[0];             if (userProfileProperties[1] !== null) {                 document.getElementById("Userprofileimage").src = userProfileProperties[1];             }         },         error: function (jqxr, errorCode, errorThrown) {             console.log(jqxr.responseText);         }     }); }    Error:     "{\"error\":{\"code\":\"-1,        Microsoft.SharePoint.Client.InvalidClientQueryException\",\"message\":{\"lang\":\"en-US\",\"value\":\"The method         GetUserProfilePropertiesFor cannot be invoked as its parameter propertiesForUser is not supported.\"},\"innererror\":        {\"message\":\"The method GetUserProfilePropertiesFor cannot be invoked as its parameter propertiesForUser is not supported.\"        ,\"type\":\"Microsoft.SharePoint.Client.InvalidClientQueryException\",\"stacktrace\":\"     With CSOM:  //SP.SOD.executeOrDelayUntilScriptLoaded(getUserProperties, 'SP.UserProfiles.js'); function getUserProperties(targetUser) {      // get the target users domain name and account name.     var tUser = targetUser.substring(7);     // Get the current client context.     var clientContext = new SP.ClientContext.get_current();     //Get PeopleManager Instance     var peopleManager = new SP.UserProfiles.PeopleManager(clientContext);     // Get the properties to retrieve     var profilePropertyNames = ["PreferredName", "PictureURL"];     var userProfilePropertiesForUser = new SP.UserProfiles.UserProfilePropertiesForUser(         clientContext,         tUser,         profilePropertyNames);     // Get user profile properties for the target user     userProfileProperties = peopleManager.getUserProfilePropertiesFor(userProfilePropertiesForUser);     // Load the UserProfilePropertiesForUser object.     clientContext.load(userProfilePropertiesForUser);     //Execute the Query     clientContext.executeQueryAsync(onRequestSuccess, onRequestFail); }    I really don't understand where the issue is. Does anyone have an idea?