Ark-kun
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 Feb8 asked Find the dimensionality of the vector space, given a “scalar multiplication table” for a set of vectors. Jan4 awarded Nice Answer Sep30 awarded Excavator Sep30 comment Generalized chi distribution Nevermind. Found the answer here: en.wikipedia.org/wiki/Rice_distribution#Moments Sep30 comment Generalized chi distribution @RossB. There are very few mentions of the Noncentral Chi Distribution on the Internet. I have a problem understanding the formulas in the Wikipedia article you've linked. The formula for the mean uses the "generalized Laguerre polynomial", but its n parameter is 1/2 (L^(k/2-1)_1/2), while the linked article only deals with integer values. Can you, please, tell me how to calculate the mean of the noncentral chi distribution? Sep29 revised Mean and variance of the product of a normally distributed random variable The integration variable is not a random variable. Sep29 suggested approved edit on Mean and variance of the product of a normally distributed random variable Sep29 comment length of Gaussian Random Vector AFAIK, the variables also need to be zero-centered to produce the Rayleigh distribution. Jul20 awarded Tumbleweed Jul13 asked Estimation covariance of the Kalman filter state Jul13 answered Kalman filter for acceleremoter and gyro May16 awarded Teacher May16 answered Interesting “real life” applications of serious theorems Apr20 comment An “additive” cryptographic hash-function that allows calculating the hash of some data from the hashes of the parts of that data. What do you think about matrix multiplication or some form of concatenation+hash (cannot think a proper function right now)? Apr20 awarded Editor Apr20 revised An “additive” cryptographic hash-function that allows calculating the hash of some data from the hashes of the parts of that data. added 108 characters in body Apr20 comment An “additive” cryptographic hash-function that allows calculating the hash of some data from the hashes of the parts of that data. Well, the $N^3$ (the size of the combination operator table) can be quite big for 1024-bit hashes. But I guess, some forms of rainbow tables could make brute-forcing faster. I wanted to use such hash for a version-control system to allow addressing parts of files. Apr20 comment An “additive” cryptographic hash-function that allows calculating the hash of some data from the hashes of the parts of that data. Why would that allow it? Suppose $h(d) = md5(md5(d[0..n/2]),md5(d[n/2+1..n]))$ $hh(h1, h2) = md5(h1, h2)$. How would that compromise the security? Apr20 asked An “additive” cryptographic hash-function that allows calculating the hash of some data from the hashes of the parts of that data. Feb16 awarded Student