I need to write this equation in latex, but I don't know how to get the vertical line and the B subscript below it. If anyone knows the operator or command, it'd be very helpful.
I'm trying to determine if there is a best practice for typesetting the "evaluated at" bar for derivatives. The three possibilities I'm thinking of are shown in the code excerpt below:  \begin{gather*} 5 + \frac{df}{dt} \Bigr\rvert_{t = 0} \\ 5 + \frac{df}{dt} \biggr\rvert_{t = 0} \\ 5 + \left. \frac{df}{dt} \right\rvert_{t = 0} \\ \end{gather*}     The \Bigr option doesn't quite reach the top and bottom of the fraction. The \biggr option overshoots the top and bottom of the fraction by a little bit. And the \left...\right option has the same height as the \biggr option, but it introduces a little extra space between the + and the fraction. I'm having trouble deciding between these options. Is there a best practice for typesetting this?
How can I stitch a panorama correctly if I moved the camera along the horizontal axis? Here in Argentina, we have . All the houses and walls on that street have some kind of mosaic stuck to it, and it's very cool. It was made by a local artist .  Because to this piece of urban art is two blocks long, I've decided to make a panorama of it, by moving myself on an horizontal axis while taking photos. I mean, I took one photo, walked one step deeper along the street, took another photo, and so on.  When I tried to stitch it in AutoPano, the following deformed thing came out:   ()  And the other side of the block:   ()  After this, I've learned about parallax error and why you have to avoid moving when making panoramas. I mean, there are a lot of connection errors on both images. Especially in the second one, the part with the corner is quite problematic to stitch because to as I moved, the perspective of the view changed a lot.  So, is there any way to stitch this kind of panorama correctly? Would this only work on plain walls? What do I need to run a D&D 5E campaign? I have GM'd several RPGs before that are not D&amp;D (Fate, Deathwatch, Star Wars). We first tried to play D&amp;D using the 3.5 edition and it went horribly — too many books and too many options with no idea of where to start.  I have been told that 5E takes care of all that and is easier and more fun so I want to try that but I would like a definitive list of what I need.  I expect that the kinds of books we need divide up like this:   Rulebook for me as GM Rulebook for players Fluff for everyone Monster book for me as GM   Links to these would be helpful as we got very confused with the 3.5 books — who should use what books confused us.  What other things do we need to play a campaign? I expect things like:   Dice: what kinds and how many of each kind, roughly. Models and maps. Do we need these? Does 5E need models and a grid or can it be played without (which is preferred)?   Is there anything else that we need that I haven't anticipated? Openshift application url: example.rhcloud.com  Custom domain: example.com  I came across this  and added the redirection rule. However, I can not access example.rhcloud.com now. My custom domain is www.example.com.  To avoid duplicate content problems, I tried this redirection.   Here is my .htaccess file:  RewriteEngine on   # Uncomment the following lines to force HTTPS #RewriteCond %{HTTP:X-Forwarded-Proto} !https  #RewriteRule .* https://%{HTTP_HOST}%{REQUEST_URI} [R,L]   # WordPress Defaults RewriteBase / RewriteRule ^index\.php$ - [L] RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule . /index.php [L]  # Redirect Https traffic to Http RewriteEngine on  RewriteCond %{SERVER_PORT} ^443$ [OR] RewriteCond %{HTTPS} on RewriteRule  ^(.*)$ http://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]   # Redirect non-www to www RewriteEngine on  RewriteCond %{HTTP_HOST} !^www\. [NC] RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]    # Redirect openshift rhcloud domain to custom domain RewriteEngine on  RewriteCond %{HTTP_HOST} ^example.rhcloud.com$ RewriteRule (.*)$ http://www.example.com/$1 [R=301,L]   Why is example.com not redirecting to ww.example.com? How do I fix this?  Also, I see that since I have https to http redirection and non www to www redirection, my blog has been loading slow. How can I reduce it to lesser number of rules?  Edit:  In chrome:   In Firefox:     The page isn't redirecting properly, Firefox has detected that the server is redirecting the request for this address in a way that will never complete.     This problem can sometimes be caused by disabling or refusing to accept cookies. Suppose that X and Y are independent Poisson distributed values with means $\theta$ and $2\theta$, respectively. Consider the combined estimator of $\theta$ $$ \tilde{\theta} = k_1 X + k_2 Y $$ where $k_1$ and $k_2$ are arbitrary constants.   Find the condition on $k_1$ and $k_2$ such that $\tilde{\theta}$ is an unbiased estimator of $\theta$. For $\tilde{\theta}$ unbiased, show that the variance of the estimator is minimized by taking $k_1 = 1/3$ and $k_2 = 1/3$. Given observations $x$ and $y$ find the maximum likelihood estimate of $\theta$ and hence show that $\tilde{\theta}$ is also the maximum likelihood estimator.   I have gotten (1) and (2) okay, but it's (3) I am having trouble with, I'd be okay if $X$ and $Y$ had the same parameter but I'm having trouble with $X$ and $Y$ having different parameters, any help would be appreciated.   NOTE   For (1) I got $k_1 = 1 - 2k_2$.   For (2) I found the variance of $\tilde{\theta}$, then differentiated and let equal to zero to minimize - therefore we get (after subbing in $k_2 = 1 - k_1/2 $) $$3k_1-1=0,$$ which when subbing in $1/3$, we see it is minimised.   Thank you. The dissolve tool (vector>geoprocessing tools>dissolve) renders some artifacts on shapes with high number of polygons. I’m using a  with 3222 polygons and I’m trying to dissolve it using the field “municipio”, but when the dissolve tool ends calculating the new shape has some artifacts     Does anyone had a similar problem? How to work around it?  I’ve also used v.dissolve from GRASS and the dissolve polygon from SAGA, but the problem persists. I’ve used the same shapefile on ArcGIS 9.3 with the dissolve tool. None artifact/error was produced.  Edit 1  I'm trying to use the v.clean tool as sugested by WhiteboxDev. However I'm getting this error:     An error has occured while executing Python code:      Traceback (most recent call last):   File   "C:/PROGRA~1/QGISCH~1/apps/qgis/./python/plugins\processing\gui\ProcessingToolbox.py",   line 181, in executeAlgorithm   File   "C:/PROGRA~1/QGISCH~1/apps/qgis/./python/plugins\processing\algs\grass7\Grass7Algorithm.py",   line 511, in checkBeforeOpeningParametersDialog   File   "C:/PROGRA~1/QGISCH~1/apps/qgis/./python/plugins\processing\algs\grass7\Grass7Utils.py",   line 361, in checkGrass7IsInstalled   File   "C:\PROGRA~1\QGISCH~1\apps\Python27\lib\ntpath.py", line 96, in join   TypeError: object of type 'NoneType' has no len()      Python version:   2.7.4 (default, Apr  6 2013, 19:54:46) [MSC v.1500 32 bit (Intel)]      QGIS version:   2.4.0-Chugiak Chugiak, 8fdd08a      Python path:   ['C:/PROGRA~1/QGISCH~1/apps/qgis/./python/plugins\processing',   'C:/PROGRA~1/QGISCH~1/apps/qgis/./python',   u'C:/Users/CERCOTRICHAS/.qgis2/python',   u'C:/Users/CERCOTRICHAS/.qgis2/python/plugins',   'C:/PROGRA~1/QGISCH~1/apps/qgis/./python/plugins',   'C:\PROGRA~1\QGISCH~1\bin\python27.zip',   'C:\PROGRA~1\QGISCH~1\apps\Python27\DLLs',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\plat-win',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\lib-tk',   'C:\PROGRA~1\QGISCH~1\bin',   'C:\PROGRA~1\QGISCH~1\apps\Python27',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\GDAL-1.11.0-py2.7-win32.egg',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\PIL',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\jinja2-2.7.2-py2.7.egg',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\markupsafe-0.23-py2.7-win32.egg',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\python_dateutil-2.2-py2.7.egg',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\pytz-2014.2-py2.7.egg',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\win32',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\win32\lib',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\Pythonwin',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\Shapely-1.2.18-py2.7-win32.egg',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\six-1.6.1-py2.7.egg',   'C:\PROGRA~1\QGISCH~1\apps\Python27\lib\site-packages\wx-2.8-msw-unicode',   'C:\PROGRA~1\QGISCH~1\apps\qgis\python\plugins\fTools\tools',   'C:\Program Files\SpiderOak\shell_extension_lib\shared.zip']   Not entirely sure if this error is QGIS related... Any idea why I'm getting this error and how can I solve it? INNER JOIN ON vs WHERE clause Same script opened in three different ways produces three different results. Why? I have a sample script (credit goes to ):  #!/bin/bash cat &lt;(cat /etc/lsb-release)   I save this script as somename.sh in my home directory.  Now, I try to open this file in three different ways:  sh somename.sh  bash somename.sh  ./somename.sh   So, I have two questions:   Why are the outputs for the above commands different though they are running the same script?   sh produces a Syntax error bash outputs the desired result ./ gives a Permission Denied error  Why is it necessary to give the script executable permission only when running the script using ./ and not necessary in the other cases?   Thanks in advance!  EDIT: The first part might be similar to the  linked one but, I did have a second question too. Let users editing a question know if editing it would add it to the reopen queue This is sort of similar to , which was positively received, but was declined for technical reasons. I propose that users who are editing a post that was closed within the last five days be shown a notice on top of the edit form indicating that the post will be added to the reopen queue if edited, and that if one does not plan on editing the post into a state where it can be reopened, one should wait until five days after closure to make the edit. Closed questions are only added to the review queue once per closure by editing, and if a user comes by and makes a minor (yet benign) edit, the diff that reopen reviewers see is just that of the minor edit, and as such they dismiss the task as &quot;Leave Closed&quot;, which prevents it from being added to the queue again by another edit. This deprives the post author (and others interested in seeing the question reopened) of their chance to get the post reopened by editing. While some of these edits may be performed by users using (semi-)automated tools who would thus not see or overlook the warning, this will be a big help because 99%+ of users make edits solely manually and would thus see and possibly respond to such a notice. To help make this request more technically feasible, I propose that it instead only be loaded with the edit form, and that it should only be shown to users who can make binding edits. (Suggested edits occur at the time of approval, and the request to let the reviewers know has already been declined.) Here's an example of what I'm expecting:  This question was recently [closed/marked as duplicate]. This question will be added to a queue for possible reopening if you make this edit. If you are not planning to edit this post into a state where it can be reopened, please wait until [date and time after 70 days] to make your edit. If you are only making edits to the question's tags, please ignore this notice. Calling 32bit Code from 64bit Process I have an application that we're trying to migrate to 64bit from 32bit.  It's .NET, compiled using the x64 flags.  However, we have a large number of DLLs written in FORTRAN 90 compiled for 32bit.  The functions in the FORTRAN DLLs are fairly simple:  you put data in, you pull data out; no state of any sort.  We also don't spend a lot of time there, a total of maybe 3%, but the calculation logic it performs is invaluable.  Can I somehow call the 32bit DLLs from 64bit code?  MSDN suggests that I can't, period.  I've done some simple hacking and verified this.  Everything throws an invalid entry point exception.  The only possible solution i've found so far is to create COM+ wrappers for all of the 32bit DLL functions and invoke COM from the 64bit process.  This seems like quite a headache.  We can also run the process in WoW emulation, but then the memory ceiling wouldn't be increased, capping at around 1.6gb.  Is there any other way to call the 32bit DLLs from a 64bit CLR process? I was browsing PhD position offers in Europe on different websites and I was quite surprised to find that several offers contained sentences such as     University of X value equality and diversity. We strongly encourage women and BAME applicants for this position.    where BAME stands for Black, Asian and Minority Ethnicities; or     The research group aims to increase the number of women in scientific positions. Female candidates are therefore encouraged to apply.   Is it considered normal in the academic environment to discriminate between  candidates according to their race and/or gender for "egalitarian" reasons?   How is the choice of a candidate based on their gender and/or race considered "egalitarian"? How can we evaluate this series  $$\sum_{n=1}^\infty \frac{n^a}{b^n}?$$  Here $a$ and $b$ are positive integers. If $b=1$ then series will be diverging, in other cases, it will be converging, but how to find this sum?  Isn't there a simple solution which doesn't involve Stirling numbers? Find the highest order bit in C Start TOC from chapter 1 and also page numbering A solid sphere has charge $q$ and radius $R$. Find the potential at a point a distance $r$ from the center of the sphere where $r&gt;R$, using infinity as the reference point.  My attempt:  From Gauss' theorem we may deduce that $\displaystyle\mathbf{E}=\frac{1}{4\pi\epsilon_0}\frac{q}{r'^2}\hat{\mathbf{r}}$ where $r'$ is the distance of an arbitrary point from the center of the sphere provided $r'&gt;R$.  $V=-\int_\infty^\mathbf{r}\mathbf{E}\cdot d\mathbf{l}$  My question: What is $d\mathbf{l}$? Since we are traversing in the direction opposite to $\hat{\mathbf{r}}$, I think it should be $-dr'\hat{\mathbf{r}}$. But when I use it to find $V$, I get a sign error. Please help! I have been/am being taught that end punctuation should always go inside quotes. For example, you are supposed to write:     Marvin thought it was "awful."   The problem is I do not see how does this make sense. Intuitively, I always wrote:     Marvin thought it was "awful".   as that makes more logical sense — you want a quote to be an exact replication of what somebody else said, so why should you add punctuation inside?  I always thought it made more sense to not touch the quote and add anything after or before if it must be added.  So, why should I put end punctuation inside quotes? Where can I find a standalone installer for Windows 7 Service Pack 1? Looking for way to copy first line of text file to end of every line $H_0(X,A) = 0 \iff A \cap X_i \neq \emptyset \forall $ path-components $X_i$ I've been doing some more exercises in , in particular the following:  Show that $H_0(X,A) = 0$ iff $A$ meets each path-component of $X$.  "$\Leftarrow$": Let $x_i \in A \cap X_i \neq \emptyset \forall $ path-components $X_i$. Then for any $x \in X_i$ there is a path $\gamma$ from $x_i$ to $x$. They therefore differ by a boundary: $\partial \gamma = x - x_i$ and therefore $\{&#160;x \} = \{ x_i \}$ in $H_0(X,A) $. Therefore $H_0(X,A) = 0$.  "$\Rightarrow$" Now for this direction I'm not so sure and I'd be glad if you could give me a hint. Let $H_0(X,A) = 0$. By definition, the relative homology group is calculated from the following sequence of chain groups:  $$ 0 \rightarrow C_0(A) \rightarrow C_0(X) \xrightarrow{\partial_1} C_0(X) / C_0(A) \xrightarrow{\partial_0} 0$$  Then $H_0(X, A) = H_0(C_0(X) / C_0(A)) = ker \partial_0 / im \partial_0 = (C_0(X) / C_0(A) ) / im \partial_1 = 0$.  There are two cases where this equality holds:  (i) $C_0(X) / C_0(A) = 0$  (ii) $im \partial_1 = C_0(X) / C_0(A)$  In case (i), $A \cap X_i \neq \emptyset$ for all $X_i$.  In case (ii) I'm not sure how to proceed. Can you give me a hint? Many thanks for your help!  Edit Or maybe I could do the second direction like this:  $$0 = H_0(X,A) = \oplus_i H_0(X_i, A) \implies  H_0(X_i, A) = 0 \forall i$$  $$ \implies A \cap X_i \neq \emptyset \forall i$$? So I really like the tag cloud on Climate Deal. Is there anyway we could get something similar to this on StackOverflow? I don't necessarily mean that we should replace the interesting/ignored tags with this but something like this on the front page would be nice. How to use paging in a WFS query? I am running a GetFeature request against a WFS server which does not support to download all data at once. Can I use ogc:PropertyIsGreaterThanOrEqualTo to split the dataset into chunks at download them step by step? I wonder how I can construct the actual URL to include the paging filter. Here is what I tried:  http://example.com/wfs.aspx?request=GetFeature&amp;service=WFS&amp;version=1.1.0 \ &amp;typeName=example:example&amp;maxFeatures=50000 \ &amp;FILTER=&lt;ogc:Filter xmlns:ogc="http://www.opengis.net/ogc"&gt; \ &lt;ogc:PropertyIsGreaterThanOrEqualTo&gt;&lt;ogc:PropertyName&gt;OBJECTID&lt;/ogc:PropertyName&gt; \ &lt;ogc:Literal&gt;50000&lt;/ogc:Literal&gt;&lt;/ogc:PropertyIsGreaterThanOrEqualTo&gt;&lt;/ogc:Filter&gt;   This is not a valid URI though... That's why uri-encoded the filter part:  http://example.com/wfs.aspx?request=GetFeature&amp;service=WFS&amp;version=1.1.0 \ &amp;typeName=example:example&amp;maxFeatures=50000 \     &amp;FILTER=%3Cogc%3AFilter%20xmlns%3Aogc%3D%22http%3A%2F%2Fwww.opengis.net \ %2Fogc%22%3E%3Cogc%3APropertyIsGreaterThanOrEqualTo%3E%3Cogc%3APropertyName%3EOBJECTID \ %3C%2Fogc%3APropertyName%3E%3Cogc%3ALiteral%3E50000%3C%2Fogc%3ALiteral \ %3E%3C%2Fogc%3APropertyIsGreaterThanOrEqualTo%3E%3C%2Fogc%3AFilter%3E   This actually works. Is there a "nicer" way to do this?