I have a git repository which has several commits into different sub-directories and I want to cut the repository in two in the following way:  /   sub1/   sub2/   sub3/   -&gt;  /   sub1/   The individual subs have evolved to a point where sub1 should be an independent repository. Also there isn't a single commit that touches more than one sub.  So, I'd like to somehow extract a new repository that only takes commits made into sub1 while leaving all other stuff out. But I want to keep the history (but not have the commits related to sub2 nor sub3).  Note: I vaguely remember there to be some command to do this, but I never used it myself and don't remember what it was called, so I cannot search for it.
I have a  repository which contains a number of subdirectories. Now I have found that one of the subdirectories is unrelated to the other and should be detached to a separate repository.  How can I do this while keeping the history of the files within the subdirectory?  I guess I could make a clone and remove the unwanted parts of each clone, but I suppose this would give me the complete tree when checking out an older revision etc. This might be acceptable, but I would prefer to be able to pretend that the two repositories doesn't have a shared history.  Just to make it clear, I have the following structure:  XYZ/     .git/     XY1/     ABC/     XY2/   But I would like this instead:  XYZ/     .git/     XY1/     XY2/ ABC/     .git/     ABC/
Although we can create or update fieldsets using salesforce UI but Is there any way to insert or update FieldSets using apex code (using metadata or API calls) ? In natural language parsing, what is the feature function? I'm working in the area of natural language processing, to be specific I'm reviewing the parsers that take advantage of data-mining techniques.   I've read an introduction to natural language processing, specifically the  by Della Pietra and others. In that paper, the authors explain that features are indicator functions that take into account certain aspects of the text. The problem is that this aspects affect the maximum entropy function.  In the case of parsing, I have problems understanding the concept of features. For parsing one must have:   Two sets, $X$ for the sentences and $Y$ for the parses For each sentence $x \in X$, one must have the N-best list of candidate parses; denoted $GEN(x) \subset Y$. Training samples $(x_j,y_j)$. The $x_j$ are sentences and the $y_j$ are parses. And a feature mapping $\Phi(X,Y)$ that maps each pair (x,y) to a vector of feature values.   The problem of parsing will consist of finding the weight vector such that the following expression is minimized  $$ -\sum log P(y_j|x_j,w) + \lambda ||w||_1 $$  where   $$ P(y_j|x_j,w) = \frac{exp \{w^T \Phi(x_j,y_j)\}   }{ \sum_{u \in GEN(x)} exp\{ w^T\Phi(x_j,u) \}  } $$  My question is, what are the features in this case? Some codified version of the parsing tree? Are the features a statistical concept?  I will also appreciate any bibliography that can be useful in tackling this issue.  UPDATE: I've talked to a professor and he had just told me that the features are obtained after doing a classification algorithm based on the parse-tree. Do you know what kind of classification is done with the parse tree? Taking Seats on a Plane Let $X_1$ and $X_2$ be two independent exponential random variables with the PDFs $f_{X_1}(x_1)=\lambda_1 \exp(-\lambda_1 x_1)$ and $f_{X_2}(x_2)=\lambda_2 \exp(-\lambda_2 x_2)$.   Let $X= \frac{X_1X_2}{X_1+X_2+a}$ be a r.v. for which I want to derive the CDF, where $a$ is a positive constant.  In other words, I need to calculate $\mathbb{P}\{X &lt;x \}$.  Any ideas or hints?  Edit (attempt):  Using a similar approach to that used , we have $X_1 \in [0, \infty)$ and  $X_2 \in [0, \frac{x(x_1+a)}{x_1-x})$. The latter interval results from: $\frac{x_1x_2}{x_1+x_2+a} &lt; x$, thus $x_2(x_1-x)&lt;x(x_1+a)$ which implies $x_2 &lt; \frac{x(x_1+a)}{x_1-x}$; but I am not sure if this is correct since $x_1-x$ can sometimes be negative (?). Based on the above, we can write: \begin{align}  \mathbb{P} \{ \frac{X_1X_2}{X_1+X_2+a} &lt; x \}  &amp; = \int_{x_1=0}^\infty \int_{x_2=0}^{ \frac{x(x_1+a)}{x_1-x}} \lambda_1 \exp(-\lambda_1 x_1) \lambda_2 \exp(-\lambda_2 x_2)  dx_2 dx_1  \\ &amp;= \int_{x_1=0}^\infty \left(1-\exp(-\lambda_2\frac{x(x_1+a)}{x_1-x}) \right) \lambda_1 \exp(-\lambda_1 x_1) dx_1  \\ &amp; = 1-\lambda_1 \int_{x_1=x}^\infty \exp(-\lambda_2\frac{x(x_1+a)}{x_1-x} ) \exp(-\lambda_1 x_1)   dx_1 \end{align} In the last equality: for the integral of $\lambda_1 \exp(-\lambda_1 x_1) dx_1$, I suppose that $x_1 \in [0,\infty)$, whereas for the second term I suppose that $x_1 \ge x$ (since $x_2$ should be positive) (?).  Is my approach correct ? How to find historical stock price for a de-listed or defunct company? With services like Google Finance or Yahoo Finance it is very convenient to find the historical stock price metric of a listed company, but if the company is not listed, I can't find the data.  For example, I want to see the price metrics for Macromedia, which had been listed in 1993 on NASDAQ (MACR), then acquired by Adobe in 2005. How could I find its historical price metrics? I have a follow up question to this question:   My question is: when should you add a comma when starting a letter/email with     Hello John,      It was fun to see ...   I am pretty sure that a comma goes after the name, but lately I have seen several people (academics) write      Hello, John,       It was fun to see ...   with a comma after the Hello.  I am wondering when a comma there is appropriate.    I see this question  but I am wondering about the situation where you have a comma after the name also. I co signed on a bank loan to finance the purchase of a car for my brother in Florida.  Only his name is on title, registration and insurance policy. Would I be liable and can I be sued by another person if he were in an accident? How do I take a screenshot on my Mac? What's the easiest way to take a screenshot of my Mac?  I've used Grab.app, but it's a bit annoying just to get a quick screenshot. Is there a faster way? How can I force a long string without any blank to be wrapped? I have a long string (a DNA sequence). It does not contain any whitespace character.  For example:  ACTGATCGAGCTGAAGCGCAGTGCGATGCTTCGATGATGCTGACGATGCTACGATGCGAGCATCTACGATCAGTCGATGTAGCTAGTAGCATGTAGTGA   What would be the CSS selector to force this text to be wrapped in a html:textarea or in a xul:textbox? Does the command pwd in a shell script output the directory the shell script is in? Im trying to craft a regex that only returns &lt;link&gt; tag hrefs  Why does this regex return all hrefs including &lt;a hrefs?       (?&lt;=&lt;link\s+.*?)href\s*=\s*[\'\"][^\'\"]+        &lt;link rel="stylesheet" rev="stylesheet"      href="idlecore-tidied.css?T_2_5_0_228" media="screen">     &lt;a href="anotherurl">Slash Boxes&lt;/a>   thank you I am running a query like   select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d';   on table that looks like                                      Table "public.students"           Column       |            Type             |             Modifiers                   -------------------+-----------------------------+------------------------------------      id                | uuid                        | not null default gen_random_uuid()      school_id        | uuid                        |  Indexes:     "students_pkey" PRIMARY KEY, btree (id)     "students_school_id_idx" btree (school_id)   The query plan for the select statement with just where looks like below-  explain select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d';                                             QUERY PLAN                                             --------------------------------------------------------------------------------------------------  Bitmap Heap Scan on students  (cost=581.83..83357.10 rows=24954 width=16)    Recheck Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)    -&gt;  Bitmap Index Scan on students_school_id_idx  (cost=0.00..575.59 rows=24954 width=0)          Index Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)   This is fairly fast.  Now we add order by to the query with id that degrades the query.(Such a query is generated by Rails like student.first with some condition)  explain select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d' order by id asc limit 1;                                                  QUERY PLAN                                                  ------------------------------------------------------------------------------------------------------------  Limit  (cost=0.43..488.51 rows=1 width=16)    -&gt;  Index Scan using students_pkey on students  (cost=0.43..12179370.22 rows=24954 width=16)          Filter: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)   How can I improve the speed to return the results of this query? Currently there are around 4990731 records in the table and is taking more than 2 minutes! Its running on RDS with db.t2.medium instance.  UPDATE After running Analyze students;  explain select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d' order by id asc limit 1;                                                        QUERY PLAN                                                         -----------------------------------------------------------------------------------------------------------------      Limit  (cost=8.46..8.46 rows=1 width=16)        -&gt;  Sort  (cost=8.46..8.46 rows=1 width=16)              Sort Key: id              -&gt;  Index Scan using students_school_id_idx on students  (cost=0.43..8.45 rows=1 width=16)                    Index Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)      explain analyze select id from students where school_id='67153fb1-8f79-441d-a747-ca3778cf6d3d' order by id asc limit 1;                                                                           QUERY PLAN                                                                              -----------------------------------------------------------------------------------------------------------------------------------------------------------     Limit  (cost=8.46..8.46 rows=1 width=16) (actual time=1.853..1.855 rows=1 loops=1)      -&gt;  Sort  (cost=8.46..8.46 rows=1 width=16) (actual time=1.851..1.852 rows=1 loops=1)            Sort Key: id            Sort Method: quicksort  Memory: 25kB            -&gt;  Index Scan using students_school_id_idx on students  (cost=0.43..8.45 rows=1 width=16) (actual time=1.841..1.843 rows=1 loops=1)                  Index Cond: (school_id = '67153fb1-8f79-441d-a747-ca3778cf6d3d'::uuid)     Planning time: 0.145 ms     Execution time: 1.874 ms Should I use static_cast or reinterpret_cast when casting a void* to whatever Both static_cast and reinterpret_cast seem to work fine for casting void* to another pointer type. Is there a good reason to favor one over the other? Acount suspension reason is only shown on the main site profile not meta How can I have a horizontally shaded frametitle in beamer? This question is similar to . I want to achieve the horizontal shading effect in the frametitle and when I use  \setbeamertemplate{frametitle}[horizontal shading] [left=red, right=white]   I get compilation errors:  LaTeX Error: Missing \begin{document}. [[]   Vertical shading seems to work just fine. Add air resistance to projectile motion I am given an initial x and y position and initial velocity and I was asked to graph the trajectory in 1 second intervals.  This is what I have so far:  If $x_0 = 1, v_{0x} = 70, y_0 = 0, v_{0y} = 80, a_x = 0, a_y = -9.8$, and time will be 0,1,2,3... and so on.  Using these equations on every second you can find the plot will be a bell shaped with the highest point being ~ 325 m at about 600 seconds:   $$ x = x0 + (v_{0x})t + 1/2((a_x)t^2) $$ $$ y = y0 + (v_{0y})t + 1/2((a_y)t^2) $$  Usually in physics, we are taught in perfect condition with no air resistance. But what if there was air resistance? How would it affect this problem? How can i add it to my calculations and see what the difference is? Network-wide Help Center bug What does a confidence interval with a negative endpoint mean? How can I break on an unhandled exception in ASP.NET? Is there a subtle difference between "somebody" and "someone", "anybody" and "anyone"? Are there any subtle differences between "somebody" and "someone", or can they be used completely interchangeably? Similarly, can you imagine a situation in which you would prefer "anybody" to "anyone" or vice versa?