I understand the concepts of L1 and L2 loss (i.e. L1 loss will force some parameter coefficients to zero while L2 will only make them approach zero). What do these do when implemented in XGBoost? Does L1 loss prune the tree more significantly than L2 loss?
This question pertains to L1 &amp; L2 regularization parameters in Light GBM. As per official documentation:  reg_alpha (float, optional (default=0.)) – L1 regularization term on weights.  reg_lambda (float, optional (default=0.)) – L2 regularization term on weights  I have seen data scientists using both of these parameters at the same time, ideally either you use L1 or L2 not both together.   While reading about tuning LGBM parameters I cam across one such case: Kaggle official GBDT Specification and Optimization Workshop in Paris where Instructors are ML experts. And these experts have used positive values of both L1 &amp; L2 params in LGBM model. Link below (Ctrl+F 'search_spaces' to directly reach parameter grid in this long kernel)      I have seen same in XGBoost implementations.  My question is why use both at the same time in LGBM/XGBoost.  Thanks.
How do you attach a debugger to a Web service? I am using a Web service. Can anybody tell me how to debug through it? How can I improve Light Armor as an Archer? I play as an archer, which means sneaking and killing foes off at long range. Problem is, once a creature gets too close to me, I am in a world of troubles. (A random dragon encounter is fair game if I can snipe it off, but a random bear encounter is the thing I fear mostly. Three strikes of such a vicious beast and I drop dead.)  At short range, I use a one-hand sword with shield, but I do not want to put much perks into those skills, as I want to be a sneaky archer first.  Which leaves Light Armor. But to get certain perks I need some skill points, e.g., 30 points are required for the "Custom Fit"- and 40 for "Agile Defender 2/5"-perk. Yet I have no clue how to accumulate those points.  Many enemies won't even see me, so I seldom will be hit. Getting hits means getting skills point. Letting some enemies come close to me and let me hit me on purpose sometimes helps, but since I cannot stand much damage I mostly die erasing any hard earned process.  So is there a teacher for Light Armor like there is for other skills? And if not, how should I go on to improve the Light Armor skill? Why did Dumbledore 'put on' the Resurrection Stone (Ring)? Why are the longer edges being beveled more? Proof of one inequality $a+b+c\leq\frac{a^3}{bc}+\frac{b^3}{ca}+\frac{c^3}{ab}$ How to prove this for positive real numbers? $$a+b+c\leq\frac{a^3}{bc}+\frac{b^3}{ca}+\frac{c^3}{ab}$$  I tried AM-GM, CS inequality but all failed. Repeating an equation including its content and number I would like to re-use equations with the same content and number. I know that the thmtools package has a restatable environment to do this for environments (like in ), but I would also like to do this with a single equation that is only part of some environment.  I had a look at the following questions which only aim at repeating the equation number but typing the whole equation twice (the first three) or repeat the content of the equation without a number (the last one):         Based on the answers provided there and on the  I tried to create a macro \restatableeq for restable equations like this:  \documentclass{article}  \usepackage{amsmath}  \newcommand{\restatableeq}[3]{\label{#3}#2\xdef#1{\unexpanded#2\unexpanded\tag{\unexpanded\ref{#3}}}}  \begin{document}  \begin{eqnarray} \restatableeq{\eqone}{This &amp; is &amp; eqation 1}{eq1}\\ Another &amp; simple &amp; equation \end{eqnarray}  \begin{eqnarray} One &amp; more &amp; equation\\ \restatableeq{\eqtwo}{This &amp; is &amp; eqation 2}{eq2} \end{eqnarray}  Here, we use (\ref{eq1}) and (\ref{eq2}) again: \begin{eqnarray*} \eqone\\ \eqtwo \end{eqnarray*}  \end{document}   Unfortunately, it does not work and yields:  ! Missing { inserted. &lt;to be read again&gt;                    T l.10 ...ableeq{\eqone}{This &amp; is &amp; eqation 1}{eq1}                                                   \\ ?   My guess is that the &amp; symbols are not treated as intended but I may well be wrong there.  How can I define a command like \restatableeq that allows me to re-use equations with the same content and number in a setting like in this example (and give it a label such that I can still use \ref as usual in addition to that)? If there is a unique left identity, then it is also a right identity Let $(R,+,\cdot)$ be a ring, and $e \in R$ be an element such that $ea=a$ for all $a\in R$. I'm trying to prove that if $e$ is unique with this property, then $ae=a$ for all $a\in R $.  So far I have $e^2 = e$ (using uniqueness), but I am stuck. I saw a proof of this fact for groups which used the existence of inverses, which we don't have here. I wonder if the result is really true here. Can someone help? Thanks. Let $f_n(x) : \mathbb{R} \rightarrow \mathbb{R}$ be defined as $\dfrac{x}{n}$. Is $f_n$ uniformly convergent?   With "$(a_n)$ is limited and $(b_n)$ converges to 0 $\Rightarrow (a_nb_n)$ converges also to 0" i would guess that $x\cdot \dfrac{1}{n}$ converges uniformly but $x$ is not limited in this case. So does ist converge uniformly or not? Why does the direction of a dipole moment go from negative to positive charge? An  is defined as $p = q\times d$ (for two point charges $\pm q$ separated by a distance $d$).    What is the physical meaning of this quantity?  Why does the direction of the electric dipole moment go from the negative charge to the positive charge? Another way of saying this, why electric dipole moment is a vector quantity? Can I enable AHCI after installing Windows 7 in a SATA drive that was on IDE mode? What is a "slug" in Django? How much to store luggage at SFO for 24 hours? Unable to start XAMPP using sudo in Desktop Entry How can I diagnose and repair missing drive space? Mouse pointer and keyboard Freeze when pluggin in external hard drive so as I say in the title I have this very big, annoying problem. On my new PC (HP Omen 2020, i7-10750h, Nvidia RTX 2070, 16GB RAM) when I connect an external hard drive (precisely an WD My Passport Ultra, 3TB) I get occasionally mouse and keyboard freezes. Practically, the system becomes unusable. The mouse and keyboards works, they even show in device manager, but from time to time (too often) they &quot;freezes&quot;: mouse pointer freeze, and it won't respond to my input, and keyboard too, if I type something it will not respond. First I thought this was a behaviour due to bad drivers, or something related to my new PC, the fact that it has USB 3.1 ports. But then I've noticed that this fact happens only when I connect my WD Hard Disk (which is USB 3.0) to my pc. I've tried some stuff online, suggesting to update drivers, change some windows settings, but with no success. My guess is that the hard disk and the mouse-keyboard does interfere with each other in some ways. I guess that it's a software problem, at driver levels maybe, not a physical one. When the mouse doesn't respond, I've tried to use the touchpad on the notebook, and it does work. So it's not a windows freeze, it's just the device (mouse-keyboard-receiver) that doesn't respond. The mouse and keyboard are from Logitech, bot connected with the Unifiying receiver (a wireless receiver they provide for the mouse and the keyboard). Model: MX Anywhere 2S for the mouse, K360 for the keyboard. Please, help me solve this problem, monday I start taking my engineering class lessons from MS Teams, and I need my pc up and running and well responsive (I need to access data from the hard disk while I take classes). PS: I've seen that there are some other questions like this in the forum, but none of them seems to provide a solution to the problem. I would also change the external hard drive in the future, but I need to know that the problem with this one won't show with another hard drive, or other devices. I've already sent this very same post to Microsoft community, I really need help with this thing otherwise it will be a problem following my online classes. Thank you if you will try to help me EDIT: On the notebook in question I have 4 USB 3.1 Ports, with two ports on each side, and a single Type-C Thunderbolt port (I'm not counting that one cause both the hard disk and the logitech receiver are USB 3.0 type A connectors). I've already tried switching USB port, connecting the WD Hard Disk to another port, doing the same on the logitech receiver, and I've even tried putting them one on the left side and the other to the right side, to minimize &quot;interference&quot; as someone suggested. But nothing, I still got this problem, which seems driver-related. Hope this will give more info Java obfuscators I'm looking for a good Java obfuscator.  I've done initial research into the following Java obfuscators: proguard, yguard, retroguard, dasho, allatori, jshrink, smokescreen, jobfuscate, marvin, jbco, jode, javaguard, jarg, joga, cafebabe, donquixote, mwobfu, bbmug, zelix klassmaster, sandmark, jcloak, thicket, blufuscator, and java code protector.  I tried proguard and it has a really nice GUI, seems really stable, and seems to be the most popular, but it seemed to not like some enumeration on a referenced jar file (not within the code I was trying to obfuscate) which was weird.  Yguard seems to require some interaction with ant, which I didn't know too much about.  What is a good java obfuscator?  It doesn't need to be free, it just needs to work well and be easy to use. Merging bib files from within LaTeX induction proof: $\sum_{k=1}^nk^2 = \frac{n(n+1)(2n+1)}{6}$ I encountered the following induction proof on a practice exam for calculus:  $$\sum_{k=1}^nk^2 = \frac{n(n+1)(2n+1)}{6}$$  I have to prove this statement with induction.  Can anyone please help me with this proof? why does loop-cut-and-slide ignore some faces but not others? I am a graduate student in mathematics who would like to learn some classical mechanics. However, there is one caveat: I am not interested in the standard coordinate approach. I can't help but think of the fields that arise in physics as sections of vector bundles (or maybe principal bundles) and would love an approach to classical mechanics or what have you that took advantage of this.  Now for the questions:   Is there a text book you would recommend that phrases the constructions in classical mechanics via bundles without an appeal to transition functions?   What are the drawbacks to this approach other than the fact that it makes computations less doable? (if it does that)   Are there benefits to thinking about things this way, ie would it be of benefit to someone attempting to learn this material to do it this way?