Karl Hardr
Reputation
220
Top tag
Next privilege 250 Rep.
 Feb 10 awarded Yearling Dec 16 comment Convex optimization with groups Many thanks for all the inputs. I need to implement this in java, so I guess I'll end up using something like jOptimizer. But thanks for the references anyway :) Dec 16 comment Convex optimization with groups @JohanLöfberg Ok, I get it. Thanks a lot. Do you know whether one can conclude the existence of solutions already from this form? Dec 16 comment Convex optimization with groups Could you elaborate on the notation? The way I regard it, x and y are statically linked (see equality constraint). Therefore I should only be optimizing for one variable, right? After all, I want to optimize the utility for the aggregate resources assigned to each user, and which resources are demanded by what user is preliminarily known. Dec 15 asked Convex optimization with groups Dec 7 comment Find the fixed points Thank you @Adam, I've added the case $b=0$ to the solution. Dec 7 revised Find the fixed points added 119 characters in body Jul 30 awarded Commentator Jul 30 comment Modified balls and bins What have you tried so far? Jul 30 comment Represent code in math notation What is the purpose of this? Jun 20 comment Roulette probability If your probability for winning is $p$, the probability for losing is $q = 1-p$. Independent random events(such as your roulette example or throwing a dice), allow you to multiply the probabilities. E.g. scoring 6 twice in a row with a dice has a probability of one out of six, times one out of six: $\frac{1}{6}*\frac{1}{6}=\frac{1}{36}$. Jun 19 answered What does ($\ln x$) or ($\log x$) mean? Jun 18 answered Probability, combinations with repetition Jun 18 comment Probability, combinations with repetition Don't you have any information on the respective quantities of the different fruits? Jun 18 comment How to write two for loops in math notation? $$(1+2+3+4+5)^2$$ Jun 18 comment state space model Basically, your fist equation is your system model, i.e. how you expect your system to move on to step 11 given step 10. $n(t)$ denotes the modeling error, e.g. errors due to numerical calculations. The second equation describes your system observation i.e. the output of your sensors and can be anything from velocity to torque or position. The error term $v(t)$ denotes the measurement error which stems from non ideal sensors. Jun 18 comment Solve $x^x=2x$ where $x\in\mathbb C$. I can show you how I started: The Lambert W function is given as $z=W(z)*e^{W(z)}$. What you are trying to obtain is a expression on x which matches this function. You can start with $x^x=2x$ using the logarithm you obtain $x\ln{x}=\ln{2x}=\ln{2}+\ln{x}$. Then: $$x\ln{x}-\ln{x}=\ln{2}$$ $$(x-1)\ln{x}=\ln{2}$$ $$e^{\ln{x-1}}\ln{x}=\ln{2}$$ Now we almost arrived at the desired form. However, $x-1$ is still causing troubles... Jun 18 answered Choosing balls out of a bag, replacing them by opposite colour Jun 15 revised Find the fixed points added Jun 15 answered Find the fixed points