I installed ubuntu alongside windows 8.1 and i installed correctly by creating partitions and the laptop finally says restart to use ubuntu but when i do , it agains diplays a gnu grub version showing : -try ubuntu without installing -install ubuntu -oem install -check disc for defects.  also i have no idea where my windows has gone.
I installed Windows on my computer, followed by an installation of Ubuntu. However, now I'm unable to boot into my Windows install.  What can I do to fix this?
I want to check if points layer that I have intersect with polygons layer that I have, as Boolean column in the points dataframe. I have two GeoPandas dataframes, the first one is many points and looks like this: &gt;&gt;&gt;ID  geometry 0  12  POINT (5.0279 7.4547) 1  45  POINT (6.6539 12.139) ...  and the second dataframe is one layer of many different polygons  that looks something like this: &gt;&gt;&gt;name     code   geometry 0  Desert   12     POLYGON ((5.52013 13.8902, 5.5265 13.892,...) 1  Water    24     POLYGON ((5.53756 13.88472, 5.5291 13.8791,...) ...  I'm trying to check if there is any intersection between the points layer and the regions layer. For that I have determined the crs and then used intersects : regions=regions.to_crs({'init': 'epsg:4326'}) points=points.set_crs({'init': 'epsg:4326'}) inter=points.geometry.intersects(regions.geometry)  A The script runs with the following warnings:  FutureWarning: '+init=:' syntax is deprecated. ':' is the preferred initialization method. When making the change, be mindful of axis order changes: https://pyproj4.github.io/pyproj/stable/gotchas.html#axis-order-changes-in-proj-6 return _prepare_from_string(&quot; &quot;.join(pjargs)) /opt/conda/lib/python3.8/site-packages/geopandas/base.py:39: UserWarning: The indices of the two GeoSeries are different. warn(&quot;The indices of the two GeoSeries are different.&quot;)  Then when I check the results the only value is False, like all th epoints do not intersect: inter.unique().tolist() &gt;&gt;&gt;[False]  *I saw on QGIS that the there are points that intersect and there are points that do not so there is no way this result is true *I have checked the dtypes - each one of my geodataframes has one column that is geometry and called geometry. My end goal: to add new column in the points geodataframe that will tell if it intersects the regions or not. When should N-Gons be used, and when shouldn't they? Support for N-Gons (polygons consisting of more than 4 vertices) has been in Blender for a while now, but many of us still may not know when to use them, and how to do so effectively.  In what situations do N-Gons really come in handy? When should they be just plain left out? Do they have any place in finished models? Evaluate $\sum_{k=1}^\infty\frac{x^k}{k(k+1)}$ My partner is tutoring a Civil Engineering student in maths. Conveniently, I am a civil engineer so when any maths that's confusing comes up, I can usually help out. However, we are having a problem with the summing of power series, one area where I am sorely lacking.  After spending two hours on a question, we still cannot solve it and are always left with a $k$. Admittedly, I don't fully know what I am doing.     Evaluate $\displaystyle \sum_{k=1}^\infty\frac{x^k}{k(k+1)}$.   We do know that the answer is $1 + \dfrac{1-x}{x}\ln (1-x)$.  Any hints or help in the direction to go would be very much appreciated. How can I double the newlines in an output stream I want to include some Cyrillic with a TeX Gyre Pagella text and math font document. I'm using TeXLive 2019.  As indicated in , running pdflatex on the following source works just fine:  \documentclass{article}  \usepackage[T1,T2A]{fontenc} \usepackage[russian,main=english]{babel} \usepackage{paratype} \usepackage{tgpagella} \usepackage{substitutefont} \substitutefont{T2A}{\rmdefault}{PTSerif-TLF}  \usepackage{amsmath}  \usepackage[math]{blindtext}  \begin{document}  The topologist is {\Russian Алекс\'{а}ндров}.  \blindmathpaper  \end{document}   However, running xelatex on the following surce produces output from which the indicated Cyrillic just disappears:  \documentclass{article}  \usepackage[T2A,T1]{fontenc} \usepackage[russian,main=english]{babel} \usepackage{amsmath} % load here to avoid \dddot clash \usepackage{fontspec} \usepackage{paratype} \setmainfont[Ligatures=TeX]{TeX Gyre Pagella} \usepackage{substitutefont}% \substitutefont{T2A}{\rmdefault}{PTSerif-TLF}%  \usepackage{unicode-math} \setmathfont{TeX Gyre Pagella Math}  \usepackage[math]{blindtext}  \begin{document}  The topologist is {\Russian Алекс\'{а}ндров}.  \blindmathpaper  \end{document}   Question: How should this second source be fixed so as to allow the Cyrillic to appear, too?  (I did put Map paratype-truetype.map into my local updmap.cfg file and did run updmap-user.) How to know if an object has an attribute in Python Is there a way in Python to determine if an object has some attribute?  For example:  &gt;&gt;&gt; a = SomeClass() &gt;&gt;&gt; a.someProperty = value &gt;&gt;&gt; a.property Traceback (most recent call last):   File "&lt;stdin&gt;", line 1, in &lt;module&gt; AttributeError: SomeClass instance has no attribute 'property'   How can you tell if a has the attribute property before using it? Virtualbox: OS cannot use the new extended disk space (.vdi) When is $-3$ a quadratic residue mod $p$? Visas to travel the world I understand that you have to have visas to enter some countries, but I was wondering whether you have to pay for each visa separately or you can get a visa to go everywhere. You see videos and lists on what you should pack to travel the world, but no lists on the documentation needed. Question  If $|G|=p^3$ and $G$ is not abelian show that $G'=Z(G)$  Attempt   Since $|G|=p^3$ then $G$ is solvable and let $$1\leq G^{(n-1)}\leq...\leq G^{(n)}=G,(1)$$  be its derived series.We know that $G^{(n-1)}$ is an abelian subgroup of $G$ so $|G^{(n-1)}|=p$ or $p^2$ (since $G$ is not abelian).Hence we have that $\bigg|\dfrac{G}{G^{(n-1)}}\bigg|=p$ or $p^2$ so $\dfrac{G}{G^{(n-1)}}$ is abelian $\Rightarrow G'\leq G^{(n-1)}$ so $(1)$ is $1\leq G' \leq G,(2)$.   Furthermore, $Z(G)\not=1$ (since $G$ is a $p-$group) and $\dfrac{G}{Z(G)}$ is abelian $\Rightarrow G'\leq Z(G)$  Is this correct so far? How could I continue? Statistics and causal inference? The relationship between the eigenvalues of matrices $XY$ and $YX$ If $X \in \mathbb{C}^{m \times n}$ and $Y \in \mathbb{C}^{n \times m}$ ($m \geq n$), how to prove the following?  $$\sigma (XY) = \sigma(YX) \cup \underbrace{\left \{ 0, ..., 0 \right \}}_{m-n}$$  Here, $\sigma$ denotes the set of eigenvalues/spectrum. Using Windows 10 in a virtual machine. Can it be done? I am currently running 8.1. I'd like to try out Windows 10 and if I like it upgrade. If not, I'll keep running as I am.   I've never used a virtual machine before: can Window 10 be used from a virtual machine as a "sandbox", and if so how? Android finding missing numbers Intersection of two parabolae Problem: Consider two parabolae such that their axes of symmetry form a right angle. Prove that all four points of intersection lie on a common circle (it is an assumption that there exist such four points). Could you help me obtain a non-algebraic solution? (The algebraic one I did is given below.)  Algebraic solution:  There is a very simple algebraic approach, just introduce a Cartesian coordinate system such that the parabolae are given by equations:  $$y = \alpha_1 x^2 + \beta_1 $$ $$x = \alpha_2 y^2 + \beta_2 $$  and by scaling, adding and simplifying we can get the following ordinary circle equation (the right-hand side is positive because parabolae intersect): $$ \left(x-\frac{1}{2\alpha_2}\right)^2 + \left(y - \frac{1}{2\alpha_1}\right)^2 = \frac{-\beta_1}{\alpha_1} + \frac{-\beta_2}{\alpha_2} + \left(\frac{1}{2\alpha_1}\right)^2 + \left(\frac{1}{2\alpha_2}\right)^2$$  Non-algebraic solution: ?? How can I cast int to enum? How can an int be cast to an enum in C#? How to find a point on a line at a given distance from a given point on the same line (given the equation of the line)? You are given a point P(x,y) on a line of equation ax + by + c = 0. I want another point, Q(a,b) on the same line which is at a distance d from P. There will be two points. I want to find both and know which side of P each one lies.  There are related questions in this forum, but I didn't get what I am exactly looking for. Sorry for beating around the bush, and thanks for any help... Please give me an elaborate explanation. Thanks once again!!! Hot and Week tabs not shown to non-logged in users (except on SO) Visiting a SE site without logging in, one can no longer access the tabs Hot and Week (except on StackOverflow). I believe this change hides the feature from those most likely to use it: casual, but repeated, visitors. A number of people visit SE sites such as Travel or Mathematics just to read the content. They have no intention to post, and consequently, no reason to register. It makes little sense to hide the Hot and Week lists from them.   I propose that the tabs  ... Hot | Week | Month should again be made visible to anonymous visitors on SE sites, as they are on StackOverflow. Derived template-class access to base-class member-data I am visiting a friend in Switzerland for ten days. I have already got visitor's visa for the same on my Indian passport. Particulars mentioned on my visa are:  1. 'Etats Schengen' , 2. Single entry 3. Dates of visit. &amp; 4. Type of visa : C.  I understand that having already got ‘Etats Schengen' visa, I can travel to all Schengen countries.  I am also planning to visit Paris for a day during my stay in Switzerland. However, I never mentioned this in my visa application. I am planning to take a train from Geneva to Paris and book a hotel in Paris for one night. Can I possibly plan my Paris trip this way as I have Schengen visa, or I am not allowed to travel out of Switzerland as I never mentioned this in my visa application?   Also what does Single entry on my Schengen visa means: does it mean that I can enter and leave Switzerland only once or it means that I can enter and leave the Schengen region only once.