entropy

CentOS7下Tomcat启动慢的原因及解决方案 现象 　　在一次CentOS 7系统中安装Tomcat，启动过程很慢，需要几分钟，经过查看日志，发现耗时在这里：是session引起的随机数问题导致的。Tocmat的Session ID是通过SHA1算法计算得到的，计算Session ID的时候必须有一个密钥。为了提高安全性Tomcat在启动的时候回通过随机生成一个密钥。 20-Jul-2017 02:54:56.797 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /application/apache-tomcat-8.0.27/webapps/manager 20-Jul-2017 02:54:56.848 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /application/apache-tomcat-8.0.27/webapps/manager has finished in

In a note I found this phrase: Using isolated symbol probabilities of English language, you can find out the entropy of the language. What is actually meant by "isolated symbol probabilities"? This is related to the entropy of an information source. It would be helpful to know where the note came from and what the context is, but even without that I am quite sure this simply means that they use the frequency of individual symbols (e.g. characters) as the basis for entropy, rather than for example the joint probability (of character sequences ), or the conditional probability (of one particular

Let std::vector<int> counts be a vector of positive integers and let N:=counts[0]+...+counts[counts.length()-1] be the the sum of vector components. Setting pi:=counts[i]/N , I compute the entropy using the classic formula H=p0*log2(p0)+...+pn*log2(pn) . The counts vector is changing --- counts are incremented --- and every 200 changes I recompute the entropy. After a quick google and stackoverflow search I couldn't find any method for incremental entropy computation. So the question: Is there an incremental method, like the ones for variance , for entropy computation? EDIT: Motivation for

I need to shuffle an array based on a seed number so I can get the same shuffle if I need it. For example: 1. print_r( shuffleIt( $array, 2 ) ); 2. print_r( shuffleIt( $array, 6 ) ); 3. print_r( shuffleIt( $array, 2 ) ); and 3. would show the same shuffled array but different than 2. I found this function googling: function entropy( $array, $sort_seed ) { mt_srand( $sort_seed ); $order = array_map( create_function( '$val', 'return mt_rand( );' ), range( 1, count( $array ) ) ); array_multisort( $order, $array ); return $array; } It works fine on my pc with php-cli, I always get the same array

Let's assume we have drawn n=10000 samples of the standard normal distribution. Now I want to calculate its entropy using histograms to calculate the probabilities. 1) calculate probabilities (for example using matlab) [p,x] = hist(samples,binnumbers); area = (x(2)-x(1))*sum(p); p = p/area; (binnumbers is determined due to some rule) 2) estimate entropy H = -sum(p.*log2(p)) which gives 58.6488 Now when i use the direct formula to calculate the entropy of normal data H = 0.5*log2(2*pi*exp(1)) = 2.0471 What do i do wrong when using the histograms + entropy formula? Thank you very much for any

I would like to understand how the gradient and hessian of the logloss function are computed in an xgboost sample script . I've simplified the function to take numpy arrays, and generated y_hat and y_true which are a sample of the values used in the script. Here is a simplified example: import numpy as np def loglikelihoodloss(y_hat, y_true): prob = 1.0 / (1.0 + np.exp(-y_hat)) grad = prob - y_true hess = prob * (1.0 - prob) return grad, hess y_hat = np.array([1.80087972, -1.82414818, -1.82414818, 1.80087972, -2.08465433, -1.82414818, -1.82414818, 1.80087972, -1.82414818, -1.82414818]) y_true

I'm having a lot of trouble with CF10's CFHTTP at the moment. First, my test script: <CFSET results = arraynew(1) /> <CFLOOP from="1" to="10" index="idx"> <CFSET timer_start = getTickCount() /> <CFHTTP url="https://www.google.de" method="get" result="test" /> <CFSET arrayappend(results, (getTickCount()-timer_start)/1000 & " s") /> </CFLOOP> <CFDUMP var="#results#" /> 10 CFHTTP calls in a row, the time they take gets pushed to an array; that's all. Results of our CF9 server: Results of our CF10 server: Results of our CF10 server with 5 sec delay between CFHTTP calls: I already read on the forum

The question have been asked in here http://www.gossamer-threads.com/lists/linux/kernel/1210167 but I don't see an answer. AFAIK /proc/sys/kernel/random/entropy_avail should return the size of available entropy but should not consume it. At least I don't see any reason for that. However, I have been noticing the same thing as OP for at least a year and now I executed in quick succession % cat /proc/sys/kernel/random/entropy_avail 3918 % cat /proc/sys/kernel/random/entropy_avail 3447 % cat /proc/sys/kernel/random/entropy_avail 2878 % cat /proc/sys/kernel/random/entropy_avail 2377 % cat /proc