random

问题 Data source will contain approx. 5000 records. I know that it is possible to order data randomly with orderby newid() . But data to be sorted should be paged. That means page n can not contain records from previous pages (n-1, n-2 etc). Now I think I have 2 ways to go: ordering in database, or in memory (because 5000 records is small enough to hold it in in-memory cache). For option 1 (sorting in db) I am not sure if it's possible because data should be paged. Is it possible if yes how? For

问题 I'm basically trying to do this Monte Carlo kind of analysis where I randomly reassign the participants in my experiment to new groups, and then reanalyze the data given the random new groups. So here's what I want to do: Participants are originally grouped into eight groups of four participants each. I want to randomly reassign each participant to a new group, but I don't want any participants to end up in a new group with another participant from their same original group . Here is how far

问题 I'm basically trying to do this Monte Carlo kind of analysis where I randomly reassign the participants in my experiment to new groups, and then reanalyze the data given the random new groups. So here's what I want to do: Participants are originally grouped into eight groups of four participants each. I want to randomly reassign each participant to a new group, but I don't want any participants to end up in a new group with another participant from their same original group . Here is how far

问题 In a single for loop, I use a single random seed to generate all the "random numbers". They are very random as I take one from the stream at a time, without any gap. However, in parfor, each worker uses a different random seed, therefore, the numbers obtained may have interference with each other. Therefore, they are not really random as they do not come from a single seed. Also, for my case, I do not know how many random numbers each worker needs beforehand. How can I solve this problem? 回答1

问题 In a single for loop, I use a single random seed to generate all the "random numbers". They are very random as I take one from the stream at a time, without any gap. However, in parfor, each worker uses a different random seed, therefore, the numbers obtained may have interference with each other. Therefore, they are not really random as they do not come from a single seed. Also, for my case, I do not know how many random numbers each worker needs beforehand. How can I solve this problem? 回答1

问题 I am working on an Asteroid game made in Haskell with Graphics.gloss. Now I have defined a datatype for the asteroids like this: data Asteroid = Asteroid { asteroidPos:: Point, asteroidVel :: Vector, asteroidSize :: Float } So that it has a Position defined by a point, a velocity defined by a vector and it's size. Now I want to know how I could write an instance of Random for this datatype so that a new asteroid appears at a random time, on a random place with a random velocity. Does anyone

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 2 years ago . Hi I am trying to create a dataframe of 600 rows and 18 columns in R BUT: -each row has to have only three 1's randomly in the 18 columns (for example column A,E,F with 1 and the rest with 0's) -the sum of each column has to be equal to 100 I am really stuck with this problem :(

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 2 years ago . Hi I am trying to create a dataframe of 600 rows and 18 columns in R BUT: -each row has to have only three 1's randomly in the 18 columns (for example column A,E,F with 1 and the rest with 0's) -the sum of each column has to be equal to 100 I am really stuck with this problem :(

问题 This is a seemingly common question, so I hope I don't sound redundant. But the range returned from rand() should be between 0 and RAND_MAX, however, when I do a very simple rand statement, I'm always getting returns within a very small range. This range is something like 1,4XX,XXX,XXX. I figured this might be a clock thing, so I waited thirty minutes and I'm still getting numbers in the same range. Here is some sample output from twenty minutes ago: Matthews-Macbook-Pro:Data_Structures