median

I am looking for a Ansi C implementation of a fast/efficient median filter. Any pointers? So far, I have found the following implementation, which is good but I am curious on faster ones. I only need for 1 dimension. I needed to extract a signal from very noisy CPU consumption data. Here's the Jeff McClintock median filter... Initialize the average and median to zero, then for each sample 'inch' the median toward the input sample by a small increment. Eventually it will settle at a point where about 50% of the input samples are greater, and 50% are less than the median. The size of the

I can use the median of medians selection algorithm to find the median in O(n). Also, I know that after the algorithm is done, all the elements to the left of the median are less that the median and all the elements to the right are greater than the median. But how do I find the k nearest neighbors to the median in O(n) time? If the median is n, the numbers to the left are less than n and the numbers to the right are greater than n. However, the array is not sorted in the left or the right sides. The numbers are any set of distinct numbers given by the user. The problem is from Introduction to

Hello folks, I am new to R and I am trying to compute median profit for a particular country in a data frame.I tried below one but it doesn't work for me. data("Forbes2000", package = "HSAUR") median(Forbes2000[,"sales","country"="United States"]) median(Forbes2000$sales[Forbes2000$country == "United States"]) Though it's hard to be certain without knowing what your data frame looks like. If you want to get a data.frame with the median of every country instead of just one, you could do: library(plyr) ddply(Forbes2000, "country", function(d) median(d$sales)) (You would have to install the plyr

I wrote some code that returns the median of an unsorted odd numbered array, but it does not return the median of an even numbered array. I know that in order to find the median of an even numbered array, you have to take the middle two numbers of the array, average them, and that's the median. I can't translate that into usable code. Aside from the obvious verbosity of this code, the issue seems to be with lines 7-8 and I don't see why. I prefer hints to answers, but if you rather post some fixed code, I can accept that too. def media(array) sorted = array.sort list = sorted.length if list %2

I have a start date and an end date, and am calculating the weekdays in between with the following: I created a calcuated field called CountWeekDays, and it equals: Code.getBusinessDaysCount(Fields!date_created.Value,Fields!date_closed.Value) I can get an Average of that like this: =Avg(Fields!CountWeekDays.Value) However, I cannot get the Median the same way. How can I get the median number of something that is calculated? The code I am using to get the weekday count is as follows: Function getBusinessDaysCount(ByVal tFrom As Date, ByVal tTo As Date) As Integer Dim tCount As Integer Dim

I want to modify QuickSort (in Java) so that every time Partition is called, the median of the proportioned array is used as the pivot. I have a median selection algorithm in Java that returns the kth smallest element, in this case the median. I have tons of quicksort algorithms in java that all work by themselves and sort an array. Unfortunately I can't combine those two in order to achieve the above... Everytime I try it i usually get stackoverflow erros. Can anybody show me code to see how it can be done? Thanks EDIT: For example this is a median selection algorithm that I have tried to use

I have data on monthly sales like this Company Month Sales Adidas 2018-09 100 Adidas 2018-08 95 Adidas 2018-07 120 Adidas 2018-06 155 ...and so on I need to add another column stating the median over the past 12 months (or as many as there is data for if 12 months are not available). In Python I figured out how to do it with for loops, but I'm not sure how to do in BigQuery. Thank you! Here is an approach that might work: CREATE TEMP FUNCTION MEDIAN(arr ANY TYPE) AS (( SELECT IF( MOD(ARRAY_LENGTH(arr), 2) = 0, (arr[OFFSET(DIV(ARRAY_LENGTH(arr), 2) - 1)] + arr[OFFSET(DIV(ARRAY_LENGTH(arr), 2))]

I have two vectors. One that actually holds the data (let's say floats) and one that holds the indices. I want to pass at nth_element the indices vector, but I want the comparison to be done by the vector that actually holds the data. I was thinking about a functor, but this provides only the () operator I guess. I achieved that by making the data vector a global one, but of course that's not desired. std::vector<float> v; // data vector (global) bool myfunction (int i,int j) { return (v[i]<v[j]); } int find_median(std::vector<int> &v_i) { size_t n = v_i.size() / 2; nth_element(v_i.begin(), v

I need to write a program in java to find the median of an array of three or more integers without sorting. I need some ideas. thanks You can use a Selection Algorithm . You'll also find relevant information looking for Median of Medians . You can use Quick sort partitioning step with random pivots, without sorting it. public class TestMedian { public static void main(String[] args){ int[] a = {1,9,-4,7,6,11,3,2,10}; int median; median = new Median().findMedian(a,0,a.length-1); if(a.length%2 != 0) System.out.print("the median is : "+a[median]); else System.out.print("the median is : "+(a