cool nerds of the Internet  I changed my forgotten password with root and it won't work, I'm currently using guest login which is so annoying so I was thinking I'm being a smart-head when I deleted the password with root but it still won't login!!! help me to reinstall it or whatever solution you guys might have.  PS : when I change the password with root and it gives me that "type new password" line I try to type and it doesn't do anything, like the keyboard is numb or something, the only thing that works in this stage is "Enter" so I entered two empty lines and it gave me the "password not changed" I don't even know how I changed it the first time.   HELP A SISTER
I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?
Incompatibility with mathtools and unicode-math in xelatex? I find unexpected behaviour in using mathtools in conjunction with unicode-math, which shows up if the 'range' command is used. Some incompatibilities have been noted before, so perhaps this is related. However, it only showed up for me in Texlive2016; previous versions worked as expected. In the following example I wish to draw calligraphic fonts from a different set than the main maths fonts, and some calligraphic symbols, and a regular italic bold face math, are missing.   \documentclass{article} \usepackage{mathtools}  \usepackage{fontspec} \usepackage{unicode-math} \unimathsetup{math-style=ISO,bold-style=ISO,sans-style=italic} \setmainfont{xits-regular.otf} \setmathfont{xits-math.otf} \setmathfont[range={\mathcal,\mathbfcal}]{latinmodern-math.otf} %\setmathfont[range={}]{xits-math.otf} % Try with and without this line % \begin{document} Test $a+b = \mathcal{C H G}C \mathscr{D}$ $$-\frac{a}{b} \mathcal{O} . $$ \begin{equation}     \mathrm{d} = \mathcal G(\varphi,x,y,z,t) ,  \end{equation} The symbol $\mathcal{G}$ is missing.  The following equation is wrong if I include the line  ``setmathfont[range=\{\}] \{xits-math.otf\}'' \begin{equation}     \mathup{d} = \symbf{u}(\varphi,x,y,z,t) ,  \end{equation} The glyph $\symbf{u}$ is missing. \end{document}   If mmathtools is called after unicode-math the problem does not arise, but this ordering is not recommend by the unicode-math developers.  My specific question is, is this a bug or is it something I am doing wrong? What is the iPod touch's screen sensitive to? What kinds of desktop environments and shells are available? Buffering GeoJSON file using Python? I'm trying to perform a simple buffer on GeoJSON file using Python script. I am able to do it on a shapefile using Python script and on GeoJSON using QGIS fix distance buffer tool but I can't figure out how to do it on GeoJSON using Python script. I read many posts on it but none of them include working solely on GeoJSON. I also know that it is possible to convert GeoJSON to .shp but I need to work only with GeoJSON files.  My code that works for .shp file:  from osgeo import ogr  ds = ogr.Open(r'C:\vector files\tryyy.shp', 1) in_lyr = ds.GetLayer() out_lyr = ds.CreateLayer('new_buff44',in_lyr.GetSpatialRef(),ogr.wkbPolygon) out_lyr.CreateFields(in_lyr.schema) out_defn = out_lyr.GetLayerDefn() out_feat = ogr.Feature(out_defn) bufferDist = -0.00015075  for in_feat in in_lyr:      geom = in_feat.geometry()     out_feat.SetGeometry(geom)     for in_feat in in_lyr:          geom = in_feat.geometry().Buffer(bufferDist)         out_feat.SetGeometry(geom)         for i in range(in_feat.GetFieldCount()):             value = in_feat.GetField(i)             out_feat.SetField(i, value)         out_lyr.CreateFeature(out_feat)  del ds print "finish"   When I change the file from shp to geojson in the org.Open line I get:      NoneType' object has no attribute 'CreateFields'   I thought that if I read vector file as OGR datasource object then it doesn't matter which format is the original vector file.   Can someone help me understand what I should change so that the code will work on GeoJSON files? Recover scaling factor in TikZ Does it exist some tikz register (let say \zoomfactor) that provides the curent scale factor. For example can I do something like :   \begin{tikzpicture}[scale=2]     \begin{scope}[scale=1.5]         \draw (0,0) circle (\zoomfactor);     \end{scope} \end{tikzpicture}   and to obtain circle of size 3=2*1.5 ? Exists a dedicated non-O(n²) Algorithm for avoiding to have overlapping elements? I am generating positions in a random fashion.  In the game world, instantiated elements have a radius, and shouldn't overlap.  The problem is that they will overlap because I use a usual random number generator combined with other fanciness. I can't use other random number generation algorithms where I can guarantee that the elements will never overlap.  A way to solve this is to use a spatial data structure and search for the nearest neighbors in that tree. When I insert an element into that tree, I update it accordingly.  This solution would do the work and it would be fast but my question is:  Is there a dedicated algorithm without that Tree implementation complexity which is faster than O(n²)? I am buing assamble self PC for playing games.  I am wondering, all the drivers, which are most likely for Windows, can i just use them on Ubuntu?  So if i understand you right, it will automaticaly detect the drivers, no need for installs ? or it find custom drivers for ubuntu.  This is the setup, will there be any problem with it? What does it mean to "program to an interface"? I have seen this mentioned a few times and I am not clear on what it means. When and why would you do this?   I know what interfaces do, but the fact I am not clear on this makes me think I am missing out on using them correctly.   Is it just so if you were to do:  IInterface classRef = new ObjectWhatever()   You could use any class that implements IInterface? When would you need to do that? The only thing I can think of is if you have a method and you are unsure of what object will be passed except for it implementing IInterface. I cannot think how often you would need to do that.   Also, how could you write a method that takes in an object that implements an interface? Is that possible? Visit the UK with an expired French identity card What is a good Hash function? I saw a lot of hash function and applications in my data structures courses in college, but I mostly got that it's pretty hard to make a good hash function. As a rule of thumb to avoid collisions my professor said that:  function Hash(key)   return key mod PrimeNumber end   (mod is the % operator in C and similar languages)  with the prime number to be the size of the hash table. I get that is a somewhat good function to avoid collisions and a fast one, but how can I make a better one? Is there better hash functions for string keys against numeric keys? What is the use of the square brackets [] in sql statements? Toolbar options are not displaying in Edit Profile - About me section Read columns from file, then column into an exsisting csv file Essentially, I have a csv file that contain multiple columns, called cols.csv  1,a,100 2,b,200 3,c,300 4,e,400   and I have a new csv file that has one column, called col.csv  f g h i   I want to copy the items in col.csv and append them to the end of each line in cols.csv so that, cols.csv now contains those  1,a,100,f 2,b,200,g 3,c,300,h 4,e,400,i   is that possible at all? i tried join, paste, nothing worked CSV rows to Polyline with OGR I'm not sure if I can complete this operation in one step - but someone might be able to help me.  My input file is a csv file with PointID, x, y, z and LineID columns.  I'm looking to combine all rows with the same LineID into Polyline25D using ogr2ogr with a virtual datasource (VRT file).  I can get a MultiPoint output, but can't work out how to combine multiple rows (if it's at all possible).   Alternatively, could someone help me with a python script to combine the x, y, z fields into WKT?  Input Example :  pointid y   x   z   lineid 1   320589.01   1815258.73  423.78  1 2   320573.49   1815256.71  425.04  1 3   320557.42   1815252.40  425.86  1 4   320541.64   1815248.71  426.19  1 5   320529.37   1815247.01  427.18  1 1   320588.78   1815259.35  423.43  2 2   320573.06   1815257.09  424.66  2 3   320557.00   1815253.09  425.06  2 4   320541.79   1815249.54  425.78  2 5   320529.14   1815247.74  426.22  2 6   320516.78   1815245.02  426.84  2 1   320588.62   1815260.10  423.44  3 2   320572.59   1815258.42  424.65  3 3   320556.21   1815255.29  425.13  3 4   320540.73   1815252.19  425.80  3 5   320529.02   1815248.37  426.20  3 What are Java command line options to set to allow JVM to be remotely debugged? I know there's some JAVA_OPTS to set to remotely debug a Java program.  What are they and what do they mean ? How to prove $\det(I+uv^\intercal)=1+v^\intercal u$ Let be $u,v\in\mathbb{R}^n$, then $\det(I+uv^\intercal)=1+v^\intercal u $ where $I$ denotes the identity matrix of order $n$. How to prove this?   what I did:   let be $A=\{n\in\mathbb{N}: \forall u,v \in \mathbb{R^n}, \det(I+uv^\intercal)\neq1+v^\intercal u  \} $, and suppose $A\neq \varnothing $, then for the well-orderer-principle there exists $n_0\in A$ such $n_0\leq n,\;\forall n\in A$. since $1\notin A,\; n_0\neq 1 \rightarrow n_0-1\in\mathbb{N}\setminus A  $ so: $$\forall u,v\in\mathbb{R^{n_0-1}}: \det(I+uv^\intercal)=1+v^\intercal u $$ Then, let be $u,v\in\mathbb{R}^{n_0}$, so $$\det(I+uv^\intercal)= \displaystyle\sum_{j=1}^{n_0}(-)^{1+j}a_{1j}\det(A_{1j})$$ where $a_{ij}=\begin{cases} u_iv_j+1 &amp; i=j \\ u_iv_j &amp; i\neq j \end{cases}$, and $A_{1j}$ is the  submatrix of $I+uv^\intercal$ that results deleting the i-file and j-column. Then I try to open the term for $j=1$ and try to use the relation for the new matrix of $n_0-1$ order with the determinant because it holds the same form but I have other terms which difficult me the work. Do you know other method?.  Ps. , in page 2 I've found something similar but I don't understand what it means PS. I'm taking a course of numerical analisys Is it acceptable to publish a paper using an affiliation with a former employer? Recently I've changed jobs, and consequently the field of research has also changed. But I'm still getting proposals for publications in the previous field, and it is interesting for me to accept some of them. My concern is about which affiliation to use: on one hand I gain all the knowledge in that field while working on the previous employer, also I hope they can cover my expenses related to the publication. On the other hand, I do not work for them anymore, and my current company has very little interest in my old field of research, and probably will not support it financially, but I think it is wise to mention them as well. As a compromise I'm thinking to put the previous employer in the affiliation, and the name of my new employer in the footnote, something like "currently at XYZ". Surely I'll discuss this issue with both, although the opinion of the community is also very valuable. How to format a USB drive? Looking for a (short?) story about a cryo ship looking for habitable planets I read this story/novella at least 15 years ago, probably 20 or more. It is about a ship, travelling through the universe, looking for habitable planets. Why, I can't remember. People are held in Cryo Stasis and I think they are wearing nothing in the chamber but some kind of mesh. Every time the ship gets close to a planet it wakes one or two of the people (one woman, one man?) to check it out but they never find anything good. I think in the end they wake up and discover, that they have arrived back at Earth. Other details are very vague but I seem to recall there was lots of stuff about a (blue?) light, dreaming/dreams and something about the cold, or cold blue lights or similar. Does that ring a bell for anyone? Physical Explanation for "Kolmogorov -5/3 spectrum" in Fluid Mechanics According to Kolmogorov, the energy spectrum function of a turbulent fluid is given as,  $E(k)=C\epsilon^{\frac{2}{3}}k^{\frac{-5}{3}}$  where $\epsilon$ is the energy flux and $k=\frac{2\pi}{r}$ where $r$ is the length scale.   The normal explanation I see in most physics texts and articles is that the -5/3 exponent is found purely through dimensional analysis. Obviously dimensional analysis is very useful, but often times there is a more physical explanation as well. Does anyone have any insights?