Is a base class sufficient, or is it ALWAYS worth creating an interface also?
Interface vs Base class
Why are lamps and mesh lights not illuminating anything? There are several techniques to do a 3 point lighting system.   How do you properly light a scene while using mesh planes as emission light sources?   I'm following , however despite setting up planes to act a lighting sources, the scene is still very dark.      Actual Blender file here: Can you be tripped by an AoO while standing up? I am trying to install Ubuntu 14.04 on FakeRAID along Win7.  Win 7 has been already installed, and dmraid is running.  During the installation I choose to manually partition, this is the structure:  \dev\mapper\isw_gchdghhd_Volume0 \dev\mapper\isw_gchdghhd_Volume0Op1 - NTFS Win7 loader \dev\mapper\isw_gchdghhd_Volume0Op2 - NTFS Win7 partition \dev\mapper\isw_gchdghhd_Volume0Op3 - swap \dev\mapper\isw_gchdghhd_Volume0Op5 - ext4 mounted as \ \dev\mapper\isw_gchdghhd_Volume0Op6 - ext4 mounted as \home   There is another sequence similar to above marked as "linear".  I choose \dev\mapper\isw_gchdghhd_Volume0 as boot device.  When immediately after the installation begins, an error with question marks pops up, and the installation stops. Moving a very large (40 TB) DB from a 2008 server to a 2016 server 1970s or 80s kids book: girl's life taken over by a robot doppelganger version of herself I read this book between 1980-82 but it could have been written earlier.  It's about a girl who is dissatisfied with her life, as her parents have her on a diet and she wants to be able to eat what she wants. Someone offers her a solution: to come live in this large building where she can eat all the chocolate eclairs and other junkfood she wants, while a robot doppelganger android version of herself will take her place at home and at school.  The girl agrees, but finds that after week of eating mainly eclairs, she is sick and wants to eat a decent meal. But she is not allowed to eat anything else and has found herself to be a prisoner, so she sets out to get rid of the android and get her life back.   I don't recall the ending but it seemed the 'people' behind it all might have been aliens and the building might have been a kind of ship that then disappears. Error in pip: unsupported operand type(s) for -=: 'Retry' and 'int' I'm trying install the requests, but I can't do that. I'm using Ubuntu 16.04  I tried to install using  $ sudo pip install requests   and I get the following error   Collecting requests Exception: Traceback (most recent call last):   File "/usr/lib/python2.7/dist-packages/pip/basecommand.py", line 209, in main     status = self.run(options, args)   File "/usr/lib/python2.7/dist-packages/pip/commands/install.py", line 317, in run     requirement_set.prepare_files(finder)   File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 360, in prepare_files     ignore_dependencies=self.ignore_dependencies))   File "/usr/lib/python2.7/dist-packages/pip/req/req_set.py", line 512, in _prepare_file     finder, self.upgrade, require_hashes)   File "/usr/lib/python2.7/dist-packages/pip/req/req_install.py", line 273, in populate_link     self.link = finder.find_requirement(self, upgrade)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 442, in find_requirement     all_candidates = self.find_all_candidates(req.name)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 400, in find_all_candidates     for page in self._get_pages(url_locations, project_name):   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 545, in _get_pages     page = self._get_page(location)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 648, in _get_page     return HTMLPage.get_page(link, session=self.session)   File "/usr/lib/python2.7/dist-packages/pip/index.py", line 757, in get_page     "Cache-Control": "max-age=600",   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 480, in get     return self.request('GET', url, **kwargs)   File "/usr/lib/python2.7/dist-packages/pip/download.py", line 378, in request     return super(PipSession, self).request(method, url, *args, **kwargs)   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 468, in request     resp = self.send(prep, **send_kwargs)   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 597, in send     history = [resp for resp in gen] if allow_redirects else []   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 195, in resolve_redirects     **adapter_kwargs   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/sessions.py", line 576, in send     r = adapter.send(request, **kwargs)   File "/usr/share/python-wheels/CacheControl-0.11.5-py2.py3-none-any.whl/cachecontrol/adapter.py", line 46, in send     resp = super(CacheControlAdapter, self).send(request, **kw)   File "/usr/share/python-wheels/requests-2.9.1-py2.py3-none-any.whl/requests/adapters.py", line 376, in send     timeout=timeout   File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/connectionpool.py", line 610, in urlopen     _stacktrace=sys.exc_info()[2])   File "/usr/share/python-wheels/urllib3-1.13.1-py2.py3-none-any.whl/urllib3/util/retry.py", line 228, in increment     total -= 1 TypeError: unsupported operand type(s) for -=: 'Retry' and 'int'   My python version is the 2.7 and the pip is 8.1.1 Add a section before \tableofcontents to content Let $\theta$ be a root of $p(x)=x^3+9x+6$, find the inverse of $1+\theta$ in $\mathbb{Q(\theta)}$.  So problems like this really annoy me but I did crappy on the last homework after making a lot of arithmetic mistakes so I want to run everything by you guys. This one isn't actually for homework it's just a suggested practice problem but okay lets go!!!  So I'm not sure if the method I used to do this was standard or not, I don't remember my professor showing me, but what I did first was used the canonical euclidean algorithm in $\mathbb{Q[x]}$ and wrote:  $x^3+9x+6$  $=(1+x)(x^2-x+10-\frac{4}{x+1})$  $=(1+x)(x^2-x+10)-4$  the reduced modulo  the minimal polynomial of $\theta$ i.e. $x^3+9x+6$ and so  $4=(1+x)(x^2-x+10)$  $\rightarrow$  $1= \frac{1}{4}(1+x)(x^2-x+10)$ and sooo ah $(\theta^2-\theta+10)\frac{1}{4}$ is what I believe is the inverse of $(1+\theta)$ in the quotient field... Like i said I hate these problems but ehh is this correct? On a lighter note it's finally getting cool enough for me to go on proper runs here and so that's pretty bomb! Suppose that $ f $ is entire and that for each $ z $, either $ |f(z)| \leq 1 $ or $ |f^\prime (z) |\leq 1 $. Prove that $ f $ is a linear polynomial. My question is in the title. I'm a little lost in how to solve this problem. There is a hint associated with the problem that states the following:   Use a line integral to show that $ |f(z)| \leq A + |z| $ where A = $\max\{1, |f(0)|\}$  Thanks for the help. Adding coordinate system to layout in QGIS composer? I would like to know if there is a way to add a dynamic coordinate system field into a QGIS composer layout.  I can use an expression to add many items such as document name, file path, etc but I can;t seem to figure out how to add the coordinate system? How can I disable the "Welcome, Name!" banner notification for Game Center? It was a useful answer. How can I ensure my trip to the UK will not have to be cancelled because of Brexit? I've got a trip planned to the UK in June. Due to brexit, I'm worried what changes may be introduced before my arrival.  I'm traveling on a EU / Polish passport. I'm going for a couple weeks of holiday.  Is there anything I can do right now to make it less likely any changes won't stop me at the immigration? For example, applying for some tourist visa which does not rely on the EU status? Two-Weapon Fighting & Bonus Actions Can someone give me an example of a function $f: I\to \mathbb R$ which is uniform continuous but not Hölder continuous (for any $\alpha$)? Here $I$ is an interval. If $I$ is closed and bounded then we are essentially assuming that $f$ is merely continuous.   By saying that $f$ is not Hölder continuous for any $\alpha$, I mean for all $\alpha &gt;0$,   $$\sup_{x,y\in I, x\neq y} \frac{|f(x) - f(y)|}{|x-y|^\alpha} = \infty.$$  That is, I need to find a function $f$ so that for all $\alpha$ and $M&gt;0$, there are $x, y\in I$ so that   $$ \frac{|f(x) - f(y)|}{|x-y|^\alpha} \ge M.$$  I know that $f(x) = x^\alpha$ are $\alpha$-Hölder continuous. Thus, in some sense, I am looking for $f$ which are worst than the functions $x^\alpha$ for all $\alpha &gt;0$. I have the following annoying problem with Excel 2010. I use Conditional formatting to apply bold formatting to each line of the spreadsheet that meets a condition expressed by a formula. In the "applies to", I write =$A$2:$Q$149, which is the current extent of my spreadsheet. But I want this range to grow with my spreadsheet, i.e., I want the formatting to permanently apply to the whole spreadsheet. Regularly, my "applies to" field is transformed into a complex range, that selects most lines of spreadsheet, but not all, like =$A$2:$Q$138;$A$140:$Q$147. Have you ever encountered such a problem? Is there a solution? Calculating the force required to lift a weight with a screw 0 byte file created in a simple script I have a script as below:  #!/bin/bash df -k | tr -s " " "," | awk 'BEGIN {FS=","} {print $1,$5}'|sed 1d &gt; file1.txt while read partition percentUsed do if [ $percentUsed &gt; 75 ] then echo Partition: ${partition} space is ${percentUsed} else echo Pration: $partition: OK!! fi done &lt; file1.txt   The script is executing properly, however, it is creating a zero byte file by the name 75. Any ideas why this is happening?  $ sh diskUsed.sh Partition: C:/Users/Public/Documents/CYGWIN/bin space is 75% Partition: C:/Users/Public/Documents/CYGWIN/lib space is 75% Partition: C:/Users/Public/Documents/CYGWIN space is 75% Partition: C: space is 75% Partition: H: space is 91%   $ ls -lrt total 2 -rwxrwxrwx 1 diwvibh Domain Users 284 Nov 21 04:17 diskUsed.sh -rw-r--r-- 1 diwvibh Domain Users 133 Nov 21 04:29 file1.txt -rw-r--r-- 1 diwvibh Domain Users   0 Nov 21 04:29 75 Is there any intuition or meaning regarding Cauchy-Riemann equations? Localisation is isomorphic to a quotient of polynomial ring