Loss is stuck at 67% and wont converge even with large epoch and early stopping criterion
What should I do when my neural network doesn't learn?
Why is there an emission of gamma rays? When a spontaneous radioactive reaction happens, there is an emission of gamma rays (in most cases) What causes this emission? Troubleshooting for biber I want to find a formula for the sum of this series using its general term. How to do it?  Series $$ S_n = \underbrace{1/3 + 2/21 + 3/91 + 4/273 + \cdots}_{n \text{ terms}} $$  General Term  $$ S_n = \sum_{i=1}^{n} \frac{i}{i^4+i^2+1} $$ command not running in cron (systemctl suspend) Why is the atmosphere transparent in the visible spectrum? One of the great 'coincidences' in physics is that the Sun happens to shine most brightly at exactly the wavelengths our eyes can see; it's an easy explanation that our eyes evolved to make the most out of what was available.  However, this spectral window is also , with Rayleigh scattering and the ozone layer protecting us from the UV and strong water vapour absorption in the IR until way into the radio range.  My question is: is this a coincidence? Were there geological factors that made it so? Or is it just lucky chance? (I also notice other planets in our neighbourhood weren't quite so lucky.) Or had atmospheric absorption been different our eyes would have tuned to whatever spectral window were brighter as a whole? ffmpeg is not even cutting this and other mp4s to the nearest second How was the bank robbery completed? In Now You See Me, when Morgan Freeman explains to the detective on how the Four Horseman robbed the bank, he mentions that they replaced the real money (while in the secured transport truck) with flash paper.  This does not explain how the paper in the bank got ignited, and no ignition/stimulator left in the scene as evidence.  Who/What/When ignited the flash paper in the bank on time?   There had to be some timer/delay mechanism on the platform, or something similar - but in the frames we see - there is nothing. How do I know what symbols/characters are available in a font package? I usually use xelatex, but I'm exploring pdflatex now. When loading specific fonts in xelatex, I can always know what characters the font has available, since I can inspect the font file in any font viewing program, or I can find out the hard way by just entering the unicode and see if the character is displayed in the output. But how does this work with a font package?  Say, for instance, that I would like to use phonetic symbols in the  font. How do I know whether the font has phonetic symbols (I assume it does), and how do I know what command I need to type in order to make them appear? My only resource is , but this only tells me what characters/commands there are available in LaTeX2e by default (depending on the font encoding), and what symbols I can find in specific packages. Phonetic symbols, for instance, are said to be in the tipa package. Does that mean I am locked to tipa if I want to use phonetic symbols with pdflatex?  Here's a pointless MWE:  \documentclass{article} \usepackage{gentium} \begin{document} Please give me some phonetic symbols here? \end{document} Decoupling caps, PCB layout I guess I've been somewhat ignorant when it comes to the finer details of pcb layout. Lately I've read a couple of books that try their best to lead me on the straight and narrow. Here is a couple of examples of a recent board of mine, and I have highlighted three of the decoupling caps. The MCU is a LQFP100 package and the caps are 100nF in 0402 packages. The vias connect to ground and power plane.     The top cap (C19) is placed according to best practices (as I understand them). The other two are not. I haven't noticed any problems. But then again the board has never been outside the lab.  I guess my question is: How big a deal is this? As long as the tracks are short, does it matter?  The Vref pins (reference voltage for the ADC) also have a 100nF cap across them. Vref+ comes from an onboard TL431 shunt regulator. Vref- goes to ground. Do they require special treatment like shielding or local ground?    EDIT    Thanks for great suggestions! My approach has always been to rely on an unbroken ground plane. A ground plane will have the lowest possible impedance, but this approach may be too simplistic for higher frequency signals. I've made a quick stab at adding local ground and local power under the MCU (The part is an NXP LPC1768 running at 100MHz). The yellow bits are the decoupling caps. I'll look into paralleling caps. The local ground and power are connected to the GND layer and the 3V3 layer where indicated.  The local ground and power are made with polygons (pour). It's going to be a major rerouting job to minimize the length of the "tracks". This technique will limit how many signal tracks can be routed under and across the package.  Is this an acceptable approach? I'm trying to fill out the skills section on my first character, but when I look at the character sheets in the Starter Set as examples of how to make a character, the skills that are circled have higher modifiers than their Dexterity or Strength or whatever should make them.  I've filled out all skills but those. What do I add to the ability modifier to get those numbers?   My abilities are Strength 13, Dexterity 14, Constitution 11, Intelligence 15, Wisdom 8, and Charisma 8. Proficiencies are Arcana, Athletics, History, Investigation and Stealth. My saving throws are Strength and Dexterity.   I just started D&amp;D and have the Player's Handbook, DM's Guide, Monster Manual, and the Starter Set. How to remove a repository? What packages do people load by default in LaTeX? I'm getting the impression from reading the answers written by some of the real experts here that there are quite a few little packages that just tweak LaTeX2e's default behaviour a little to make it more sensible here and there.  Rather than try to pick these up one by one as I read answers to questions (and thus risk missing them), I thought I'd ask up front what LaTeX2e packages people load by default in (almost) every document.  As this is a "big list" question, I'm making it CW.  I don't know if there are standard rules across all SE/SO sites for such questions, but on MathOverflow the rule is generally: one thing (in this case, package) per answer.  I guess that if a couple of packages really do go together then it would be fine to group them.  This is perhaps a little subjective and a little close to the line, so I'll not be offended if it gets closed or voted down!  (But please explain why in the comments.)  Also see our community poll question: Rectifiability of a curve Let $f$ be a function defined on $[0,1]$ by   $$f(x) = { 0, \text{ if } x = 0} $$ $$f(x) = { x \sin \frac 1 x , \text{ if } 0 &lt; x \leq 1} $$  Prove that the curve $\{(x, f(x)) : x \in [0,1]\}$ is not rectifiable.   I'm not sure how to approach this. The general idea seems logical, we're proving that the length of the curve is infinite, but the method seems difficult to find. Can I see images and watch movies inside the terminal emulator permission denied for root@localhost for ssh connection I just installed Ubuntu 14.04 and LAMP on that. Then, I wanted to configure my server, so tried out  tutorial.  When I give the command:  ssh root@localhost   I get : Permission denied, please try again. I have logged in as root user through the command :  sudo -i   I also tried the same, by logging in through:  sudo -s   I use the same password as that I used to log in as user, but still am getting the same error message.  Could someone help me out here?  PS: I looked into  but didn't seem to work for me. I have a little problem with the placement of my picture. I want to insert it at the end of the introduction chapter but its place is not where I want.   I think the problem become from the:  \begin{figure} ... \end{figure}   Because when I insert the picture without using \begin{figure}... the picture is at the end of the chapter as I want.   Look the picture below. Create an encrypted ZIP file in Python What do you call a group of people that move a lot? I can't think of the word to describe it. Something similar to "wanderer" or "roamer".   It's often used to describe people that don't stay in one place... not "migratory"... Self adjoint operators and trace class property This is a variation of the  questioned some time ago.  For a complex Hilbert space $H$ let $T: H \rightarrow H$ be a bounded operator. We call that $T$ is a trace-class operator if the following sum  $$\sum_{i}{\langle |T|e_{i}, e_{i} \rangle} &lt; \infty$$  converges, where $|T| = (T T^{*})^{\frac{1}{2}}$ is the absolute value of the operator.  Assume that  $$\sum_{i}{\langle Te_{i}, e_{i} \rangle}$$  converges for any basis in the space $H$. How to prove that if the aformentioned property holds then the operator is a trace class operator?  The progress on the problem is the following: Given an arbitrary bounded operator $T: H \rightarrow H$, one can use the following decomposition $$T = \big( \frac{T + T^{*}}{2} \big) ^{*} + i \big( \frac{T^{*} - T}{2i} \big) ^{*}$$  The latter line gives the decomposition $$T = A + i B$$ where $A, B$ are normal operators.  For the normal operators we can apply the spectral theorem that proposes that $T$ is unitary equivalent to  $$(UT U^{-1})(f(x)) = g(x) f(x)$$  where  $$U: H \rightarrow L^{2}(X, \mu)$$ $$g \in L^{\infty}(X, \mu)$$  Though this decomposition classify the operator in a broad sence, i see no direct way to conclude the statement. Are the any hints that may extend the previous argument? If not, are there any ways to conclude the statement? Does a conducting wire give off measurable radiation?