Just followed a machine learning example and programmed a gradient decent maximizaation to read in a 64X64X3 image vector to predict whether it was a cat or not.  The model had a parameter for every pixel*color so 12288 parameters were optimized.  It worked, a vector of parameter estimates were obtained and predictions were obtained and worked pretty well (prediction accuracy good).  How did this work, when I only had 200 samples, so p >>n. I thought we could not estimate parameters in regression when p
Regularization using methods such as Ridge, Lasso, ElasticNet is quite common for linear regression. I wanted to know the following: Are these methods applicable for logistic regression? If so, are there any differences in the way they need to be used for logistic regression? If these methods are not applicable, how does one regularize a logistic regression?
"Stack Overflow" showing up on hamburger menu for all sites to link to /questions Why does it say "Stack Overflow" instead of the site name? Consider this example from the Rogue class traits:     Trained Skills: Stealth and Thievery. From the class skills list below, choose four more trained skills at 1st level.   &nbsp;&nbsp;&nbsp;&nbsp;Class Skills: Acrobatics (Dex), Athletics (Str), Bluff (Cha), Dungeoneering (Wis), Insight (Wis), Intimidate (Cha), Perception (Wis), Stealth (Dex), Streetwise (Cha), Thievery (Dex)   The Rogue is trained in Stealth and Thievery. However, they're also included in the Class Skills section, and it invites you to: 'choose four more trained skills' from that list. This seems to be similar for all the classes.  So can you train Stealth and Thievery as a choice as well have it initially trained or the equivalent for other classes? How can I pass command-line arguments to a Perl program? I'm working on a Perl script. How can I pass command line parameters to it?  Example:  script.pl "string1" "string2" C++ Redefinition Header Files (winsock2.h) HTML table headers always visible at top of window when viewing a large table Pointwise convergent and total variation I have an HP ProBook 450 G2. Every time I shut down the computer and turn it back on after a day, the battery level decreases by about 5%. I'm sure that the computer is shut down, not in sleep or hibernate. I removed the battery from laptop and after inserting it, the battery percentage does not change. I tried updating the BIOS, disabling wake on LAN in BIOS options, and calibrating the battery several times.  Is this drain normal? If not, is it a hardware failure or can I fix it with software? Extending the User model with custom fields in Django What issues should be considered when overriding equals and hashCode in Java? What issues / pitfalls must be considered when overriding equals and hashCode? How to remove all files in a directory except hidden ones? Is there any way to see the timetable for a  bus route?  On their website I can see the routes map, but I'd me more interested in seeing where the bus is going to stop for a given route.  E.g. if a bus goes from Rotterdam to Amsterdam, I'd like to see each stop. I have read both two uses:   The combinations of a, b and c, taken two at a time, are ab, bc, ac. We can not help but noticing a harmonious combination between classic and contemporary.   Are both uses interchangeable? Perhaps substitute combinations among for combinations of in the first sentence? Any idea is appreciated. Solder new RAM in a 2015 Retina MacBook Pro I know that the new rMBPs have no "user-serviceable" RAM. But is it possible to solder a new RAM chip onto a 2015 rMBP? Given that the technician doing this is able to install the new chip without damaging anything, would it work? how to stop working for other people's thesis? Last semester, I took a course with my supervisor and he assigned me a project. This project is part of one of his student's theses. I did the project and passed the course.   Later, I was asked to upload my code for use in a paper. It turned out that the data the grad student had generated was not appropriate, and he needed to do other experiments. It later turned out there were other problems with the underlying model, and I redid a lot of that work as well.  The problem is that this other student is not really contributing at all.    Sometimes he does not come to work at all On one occasion the professor assigned us to do something, and he immediately told me he had no idea how to do it In one of our meetings with the professor, he talked 2 minutes with the prof with no slides; I talked for the other 58 with slides.    What should I do in this situation? I could not work like this, I have my own project and my thesis and stuff. I cannot dedicate my self for another student's thesis.  Question 1: how should I make this student understand this is his thesis and he should work more than me?  Question 2: How can I get off this project? I am taking another course with my supervisor, he again assigned me a term project with the same system and same grad student. I do not want to keep going like this. What should I tell to my supervisor Due to the problems we found, I think this current system is a bit of a dead end. But, I do not want to lose my connection with my supervisor; he is a good man. Why can I only change my Stack Overflow name once every 30 days? I have a  on Stack Overflow. I recently decided to change the name on my profile. I did this, but I made a spelling mistake! I wrote "Kryton" instead of "Kryten"! When I tried to fix this, a message came back saying that I can only change my profile name every 30 days. Why? Is there any way I can fix my profile name? Intuitive explanation of why $\dim\operatorname{Im} T + \dim\operatorname{Ker} T = \dim V$ I'm having a hard time truly understanding the meaning of $\dim\operatorname{Im} T + \dim\operatorname{Ker} T = \dim V$ where $V$ is the domain of a linear transformation $T:V\to W$. I've used this equation several times in many problems, and I've gone over the proof and I believe that I fully understand it, but I don't understand the intuitive reasoning behind it. I'd appreciate an intuitive explanation of it.  Just to be clear, I do understand the equation itself, I am able to use it, and I know how to prove it; my question is what is the meaning of this equation from a linear algebra perspective. How fast does the sequence $y_t$ defined by $y_{t+1}=y_t(1-y_t)$ decay to zero? The question is in the title; I'm looking for the exact decay rate. Naturally, assume the starting point $y_0$ belongs to $(0,1)$.   This is motivated by one of the answers to . Can I bring my laptop, camera on flight to USA? I am going to the US in the coming week. However, I heard that laptop and camera are not permitted to bring on board as carry-on. What are the latest rules about these larger electronics? Word for people who don't make their deadline Upper bound for norm of Hilbert space operator It is a standard result that for a bounded self-adjoint operator $T$ on a complex Hilbert space $H$, we have $\|T\|=\sup_{\|x\|=1}|\langle Tx,x\rangle|:=M(T)$, where $M(T)$ is called the  of $T$. It seems that for any bounded operator on $H$, we have $||T||\leq 2M$. Why is that so?