I am trying to synthesize a verilog file with some part of code like this(obviously i hadn't declared module and other input and output variables)  input [15:0] me;  reg [15:0] p_array [7:0]; reg abc_pqr [2:0];  abc_pqr[0] &lt;= me[0]; abc_pqr[1] &lt;= me[1]; abc_pqr[2] &lt;= me[1]; p_array[abc_pqr[0]] &lt;= me[0]; p_array[abc_pqr[1]] &lt;= me[1]; p_array[abc_pqr[2]] &lt;= me[2];   where i had used reg as index of array element, so is it not valid, though this module inside my verilog file didn't synthesized as it contain a memory element but just want to confirm that is it valid to use reg as array index? I dint find anything on net in this regards,but taking reg as index will make array act as buffer and i think it must be a valid code.
How can we read and write values in a multidimensional array in verilog, i had read in  regarding different operations that can be done on multidimensional array. like if there is a part of code like this  input [15:0] me;  reg [15:0] p_array [7:0]; reg abc_pqr [2:0];  abc_pqr[0] &lt;= me[0]; abc_pqr[1] &lt;= me[1]; abc_pqr[2] &lt;= me[1]; p_array[abc_pqr[0]] &lt;= me[0]; p_array[abc_pqr[1]] &lt;= me[1]; p_array[abc_pqr[2]] &lt;= me[2];   so is this code will work and will not produce any error?  What is the difference between these two while assigning value  "&lt;=" and "=", i had seen "&lt;=" in most of the places during passing values.
How do I prove this using question using Cauchy-Schwarz inequality? Label rows of a matrix by characters How to add label to index the rows and columns of the matrix ? because I want to number the line outside the matrix       \[     \begin{array}{lc}       \ Mat_{\varPhi to M} &amp; \left(\begin{array}{@{}ccccc@{}}             1 &amp; 1 &amp; 1 &amp; 1 &amp; 1 \\             0 &amp; 1 &amp; 0 &amp; 0 &amp; 1 \\             0 &amp; 0 &amp; 1 &amp; 0 &amp; 1 \\             0 &amp; 0 &amp; 0 &amp; 1 &amp; 1 \\             0 &amp; 0 &amp; 0 &amp; 0 &amp; 1               \end{array}\right) \\[15pt]     \end{array}     \] Maximum power transfer proof I have the following homework problem.  Consider a power supply with fixed emf $ε$ and internal resistance $r$ causing current in a load resistance $R$. In this problem, $R$ is fixed and $r$ is a variable. The efficiency is defined as the energy delivered to the load divided by the energy delivered by the emf.  When the internal resistance is adjusted for maximum power transfer, what is the efficiency?  The answer is 50% but I'm confused how this is calculated. Here is my thought process so far.  The power dissipated in the load is $I^2R$ and $\displaystyle I = \frac{ε}{r+R}$ so $\displaystyle P = \frac{ε^2R}{(r+R)^2} = \frac{ε^2}{\frac{r^2}{R} + 2r + R}$ and so power transferred to the load will be maximum when $\displaystyle \frac{r^2}{R} + 2r + R$ is a minimum. Taking the first derivative $\displaystyle \frac {d}{dr}(\frac {r^2}{R} + 2r + R) = (\frac{2r}{R} + 2)$ and this equals 0 when r = -R. The second derivative is $\displaystyle \frac{2}{R} &gt; 0$ so this point would be a minimum and therefore max power transferred when r = -R.  But having $r = -R$ doesn't make sense to me. From what I read, for maximum power transfer $r$ should equal $+R$. So I've probably done something wrong in my calculations or assumptions in the previous paragraph. Also wouldn't max power be transferred when the internal resistance is as close to zero as possible?  Can someone please show me a proof that shows why $r = R$ for max power transfer and then how to calculate the efficiency. What bends fabric of space-time? I know that mass can bend fabric of space-time, which causes gravity by making an object curve around a planet or star but is there anything else that can bend it?  Other energy sources, forces anything? Is it possible for moderators to review more than the daily limited count? Joining attributes of polygons and points by location in QGIS I have two shapefiles....   points containing a number field 'response_time' a polygon grid of square polygons containing fields including 'PNTCNT' with the number of points per polygon, calculated already using the tool 'points in polygon'   There are between 0 and 600 points within the bounds of each polygon in the grid.  I want to add fields to the polygon grid for the mean, min and max response times within each polygon, in addition to the PNTCNT field already there.  I have tried the 'Join attributes by location' tool, making the polygon layer the target and the points the join layer, and vice versa. I've selected 'take summary of interesting features'.  But I can't get the result I want. All I end up with is the polygon grid again but with an extra field 'COUNT' which replicates (or duplicates) the 'PNTCNT' field. No min, max and mean of values from the points layer.  What am I doing wrong? Is there a better way to do this? I have tried this using QGIS 1.7 and 1.8. URL of cited web site in bibliography I am using natbib with the chicago style as bibliography style. I am trying to cite a web site, but in the bibliography the URL (given in the BibTeX entry) is not printed.   Is there a simple solution to this matter? What am I doing wrong?  ok, as a little example (the entries are generated via Mendeley)  @misc{Carlson2011,    author = {Carlson, Nicholas},   booktitle = {Businessinsider.com},   title = {{How Many Users Does Twitter REALLY  Have?}},   url = {www.businessinsider.com/chart-of-the-day-how-many-users-does-twitter-really-have-2011-31/3},   year = {2011} }   and the output in chicago-style looks like this:     Carlson, N. (2011). How Many Users Does Twitter REALLY Have? Is it possible to tell a Valyrian steel sword from a very well crafted steel sword, by sight alone I'm sure in Westeros there are some incredibly well crafted steel swords, but could someone instantly spot a Valyrian steel sword over one of these?  Does Valyrian steel have any visual indications that it is Valyrian steel and not just a very well crafted steel sword?  I'm wondering, in canon, has anyone seen a sword and instantly recognised it as Valyrian steel.  For the purpose of this question, no one is allowed pick up or use the sword, so they cant feel it's weight, balance, sharpness, etc... Does separation of variables in PDEs give a general solution? When a partial differential equation is solved using the separation of variables method, is the produced solution the most general one that satisfies the equation or have we lost some forms of the solution because of the assumption that it is in the form of separated variables? How do electrons jump orbitals? My question isn't how they receive the energy to jump, but why.  When someone views an element's emission spectrum, we see a line spectrum which proves that they don't exist outside of their orbitals (else we would see a continuous spectrum).  Electrons can be released in the form of beta decay, thus proving that they are capable of traveling outside of orbitals contrary to the statement my teacher said that they stay within orbitals. Then, to add to the confusion, the older model of rings floating around a nucleus has, from what I can tell, been outdated, which would support this model. My teacher's explanation was that the electrons made a quantum jump of some kind. How do electrons move between orbitals or do we know how they jump, excluding the reason that energy causes them to jump, and why are positrons formed sometimes instead of electrons in Beta decay?  When I'm asking "how do electrons jump" I would like to know how an electron can jump between each orbital such as how it moves and how it knows where to jump since it appears to be a jump where the electron doesn't slow into a orbital position. Specifically how they jump what is this Atomic electron transition, I understand that they jump and that they do this through absorbing and releasing energy but what is this Atomic electron transition other than what is already on the wikipedia article . Search in favorited questions? I wonder if it is possible to search in just my favorited questions?  If not, can it be considered as a feature request? "Who wants ice-cream?" — Should I say "(not) I" or "(not) me"? "Items collection must be empty before using ItemsSource." I'm trying to get images to display in a WPF ListView styled like a WrapPanel as described in this old ATC Avalon Team article: .    When I try to populate the ListView with a LINQ-to-Entities queried collection of ADO.NET Entity Framework objects I get the following exception:  Exception     Items collection must be empty before   using ItemsSource.   My code&hellip;  Visual Basic  Private Sub Window1_Loaded(...) Handles MyBase.Loaded     ListViewImages.ItemsSource = From g In db.Graphic _                                  Order By g.DateAdded Ascending _                                  Select g End Sub   XAML  &lt;ListView Name="ListViewImages"           SelectionMode="Single"           ItemsSource="{Binding}"&gt;     &lt;local:ImageView /&gt; &lt;/ListView&gt;   I put a breakpoint on that line.  ListViewImages.ItemsSource is Nothing just before the LINQ assignment. I am looking for a preferably introductory text on Yang-Mills theory with mathematical basis and language. (Differential forms) I have a background in QCD and QED, however, I want to go more in details in geometrical interpretations of Yang-Mills theory. I am sorry if this question has asked before. Thanks in advance. Let $a$ and $b$ be non-zero integers, and $c$ be an integer. Let $d = \gcd(a, b)$. Prove that if $a|c$ and $b|c$ then $ab|cd$. Let $a$ and $b$ be non-zero integers, and $c$ be an integer. Let $d = hcf(a, b)$. Prove that if $a|c$ and $b|c$ then $ab|cd$.   We know that if $a|c$ and $b|c$ then $a\cdot b\cdot s=c$ (for some positive integer $s$). $(ab|c)$  Then doesn't $ab|dc$ since $ab|c$?  I feel like I'm misunderstanding my givens.    Can we say $\operatorname{lcm}(a,b)=c$,  $\operatorname{hcf}(a,b)=d$, and $\operatorname{lcd}(a,b) \operatorname{hcf}(a*b)=a*b$? Thus, $ab|dc$  as $dc = ab$. Determinant of block matrix with commuting blocks I know that given a $2N \times 2N$ block matrix with $N \times N$ blocks like   $$\mathbf{S} = \begin{pmatrix} A &amp; B\\  C &amp; D \end{pmatrix}$$  we can calculate $$\det(\mathbf{S})=\det(AD-BD^{-1}CD)$$ and so clearly if $D$ and $C$ commute this reduces to $\det(AD-BC)$, which is a very nice property.   My question is, for a general $nN\times nN$ matrix with $N\times N$ blocks where all of the blocks commute with each other, can we find the determinant in a similar way? That is, by first finding the determinant treating the blocks like scalars and then taking the determinant of the resulting $N\times N$ matrix.  Thanks in advance! Pointer to class data member "::*" I came across this strange code snippet which compiles fine:  class Car {     public:     int speed; };  int main() {     int Car::*pSpeed = &amp;Car::speed;     return 0; }   Why does C++ have this pointer to a non-static data member of a class? What is the use of this strange pointer in real code? Defining coordinate reference system with rotation in GeoServer? I am using GeoServer and have a layer in EPSG:900913 ("Google Mercator").  I need to "rotate" the map around certain point (say, 1500000, 7000000) by certain degree (say, 30 degrees clockwise). How could I define such a coordinate system based on EPSG:900913?  GeoServer's  does not work for my purposes as I need to tile the map later on.  As far as I understand this, my only option is to define an own coordinate system. For GeoServer I'd need to . The configuration seems to be straightforward, but I have a difficulty defining my rotated CRS in .  I am wondering how to apply a rotation around certain point onto a CRS like Google Mercator:  PROJCS["WGS84 / Google Mercator",    GEOGCS["WGS 84",      DATUM["World Geodetic System 1984",        SPHEROID["WGS 84", 6378137.0, 298.257223563, AUTHORITY["EPSG","7030"]],        AUTHORITY["EPSG","6326"]],      PRIMEM["Greenwich", 0.0, AUTHORITY["EPSG","8901"]],      UNIT["degree", 0.017453292519943295],      AXIS["Longitude", EAST],      AXIS["Latitude", NORTH],      AUTHORITY["EPSG","4326"]],    PROJECTION["Mercator_1SP"],    PARAMETER["semi_minor", 6378137.0],    PARAMETER["latitude_of_origin", 0.0],    PARAMETER["central_meridian", 0.0],    PARAMETER["scale_factor", 1.0],    PARAMETER["false_easting", 0.0],    PARAMETER["false_northing", 0.0],    UNIT["m", 1.0],    AXIS["x", EAST],    AXIS["y", NORTH],    AUTHORITY["EPSG","900913"]]   My questions, specifically:   How to write a WKT which transform an existing CRS? My guess would be that I need a new PROJCS wrapping an existing one and adding a PROJECTION clause. How would I found out the projection id (like Mercator_1SP above) and the required parameters (the PARAMETER clauses)? Can I "reference" EPSG:900913 in CRS WKT instead of copy-pasting the whole PROJCS clause? So I have a torus, and I need it to "telescope" open -- kind of like Pacman's death animation, but with a torus instead of a sphere.  I'm very new to 3D modeling/animating so I really have no clue how to tackle this problem.  Any advice to help me get pointed in the right direction would be most appreciated :) My processor is using a big part of my RAM memory as cache and I want to clean it up because of that; will it prejudice something?