Far away things (skybox cube) not showing up?
How do I increase the render distance?
Reprojecting LiDAR data with libLAS, error: "latitude or longitude exceeded limits"? I'm sure its a simple question and I suppose it was asked many times, but I just can't figure it out from other answers, sorry.  I use recent versions of PostgreSQL and MySQL. I have 2 tables:  CREATE TABLE authors (     id INT,     name VARCHAR )  CREATE TABLE posts (     id INT,     author_id INT,     text VARCHAR,     date DATE )   I need to select one most recent post for each author. Thanks!  UPDATE  Thanks, both links provide answers to my question with some exception. All the following queries give the same result (which one is the most efficient btw?) The issue is when there is more than one post from the same author with the same date. Then the returned result set contains all such posts. How should I modify these queries to return exactly one post per author?  SELECT p1.* FROM posts p1 LEFT JOIN posts p2 ON p1.author_id = p2.author_id AND p1.date &lt; p2.date WHERE p2.author_id IS NULL ORDER BY p1.author_id;  SELECT p1.*  FROM posts p1 INNER JOIN (   SELECT author_id, MAX(date) AS max_date   FROM posts   GROUP BY author_id) p2   ON p1.author_id = p2.author_id AND p1.date = p2.max_date ORDER BY p1.author_id;  SELECT * FROM posts p1 WHERE date = (SELECT MAX(p2.date)               FROM posts p2               WHERE p1.author_id = p2.author_id) ORDER BY author_id;  SELECT * FROM (     SELECT author_id, MAX(date) date     FROM posts GROUP BY author_id ) p1 INNER JOIN posts p2 USING (author_id, date) ORDER BY author_id; How do I cd into a directory in the home folder? How do I change directories to downloads, from the home folder, in the latest version Ubuntu 12.10? I tried cd /downloads, but it gave an error saying that there is no such directory. Is there a symbol for "unitless"? Can I find out which tags I have created? This would be interesting to know.  The tags could be highlighted on the users page for example. Can anyone help me with this?     If 738 consecutive integers are added together, where the 178th number in the sequence is 4,256,815, what is the remainder when this sum is divided by 6? How do I mount an `img` created with /bin/dd of a hard drive? How to select the rows with maximum values in each group with dplyr? Does $\sum\limits_{n=1}^\infty\frac{1}{\sqrt{n}+\sqrt{n+1}}$ converge? Does the following series converge or diverge? $$ \sum\limits_{n=1}^\infty\frac{1}{\sqrt{n}+\sqrt{n+1}} $$ The methods I have at my disposal are geometric and harmonic series, comparison test, limit comparison test, and the ratio test. Not enough space on /tmp I'm not able to run update manager as I get an error saying that there is not enough free space in the /tmp directory. I've practically cleaned out the tmp directory but the error persists.  here's df-h  /dev/loop0       13G   11G  952M  92% / udev            2.0G  4.0K  2.0G   1% /dev tmpfs           785M  920K  784M   1% /run none            5.0M     0  5.0M   0% /run/lock none            2.0G  584K  2.0G   1% /run/shm /dev/sda6        20G   14G  6.4G  68% /host  overflow        1.0M   16K 1008K   2% /tmp Consider these two ways of coining a name: 1) Bolzano's theorem, Rolle's theorem 2) the Poincare conjecture, the Kantorovich theorem. What is the difference between these ways, why do people choose one over the other?  My guess is that the main difference is when you put 's at the end of a name, you strictly imply that the theorem/conjecture was written by this very person (Bolzano wrote Bolzano's theorem). But when it is "the [Name] theorem/conjecture," it doesn't mean that the person which name is used actually created this thing, maybe he just inspired it (Poincare might have only inspired the Poincare conjecture but did not propose it).  Sometimes there is only one way: ; you can not call it hairy ball's theorem. I'm trying to solve an exercise about first order stochastic dominance, and there is this one question that I'm not able to answer.  Here are the hypothesis of the exercise:  Let Y ∼ F and Y' ∼ G, that means Y (resp. Y') has a probability law given by the distribution function F (resp. G).  Assume that Y ≥ 0 and Y' ≥ 0 and E(Y) + E(Y')&lt; ∞.  Here comes the question:  -Show that if the survival function of Y first order dominates over the survival function of Y', then if Y and Y' are independent, we have P(Y ≥ Y') ≥ 1/2.  I don't see how to use that Y and Y' are in this case independant.  Maybe I should set X=Y-Y' and then use the convolution?  Any help, would be appreciated, thanks !  Alex When studying systems of linear equations, it's nice to remind people that the last column of the coefficient matrix holds the constants.  This is often done in books by putting a vertical line between the last column and the next to last column.  What is a good way to do this in LaTex? Putting a table next to a figure Java - Method name collision in interface implementation Test -n gives unexpected result I understand test -n &lt;expression&gt; to return false if the expression evaluates to a string length of greater than 0.  Why then does the following happen?  Macbook:~ echo ${#undeclared_variable} 0 Macbook:~ test -n $undeclared_variable &amp;&amp; echo Foo Foo   Bash 4.x  My expectation is that since test -n $undeclared_variable should evaluate false, that Foo should not be echoed.  If I use [[  ]] instead of test, it works as expected. Why doesn't the Windows command prompt window maximize to the full screen size? Anyone know why doesn't the Windows command prompt window maximize to the full screen size?  To the best of my knowledge, even in the new Windows 7 the command prompt window(cmd.exe) doesn't maximize to the full screen size like all other windows. This behavior is quite annoying for me, and I'm sure to many others as well.   Note: The size of the command prompt window can be , but the size remains fixed regardless of the screen size. How do I install software using the Ubuntu Software Center? The title says it all. I'd like to know how I can install software - an example is the Chromium web browser. how much space does a given package, and dependencies, cost? Assuming I'm paying long term capital gains tax, what is the break even point where it is more worthwhile to switch from one fund to another?  For (a hypothetical) example, if I have a fund with an expected return of 3.5%, what would be the minimum expected return of another fund to make it worthwhile to pay the capital gains tax and switch to the other fund?  (I'm assuming the answer to this question is an equation involving investment horizon, capital gains tax rate, and my current taxable gains)