reduce

配置建议： 1. In MR1, the mapred.tasktracker.map.tasks.maximum and mapred.tasktracker.reduce.tasks.maximum properties dictated how many map and reduce slots each TaskTracker had. These properties no longer exist in YARN. Instead, YARN uses yarn.nodemanager.resource.memory-mb and yarn.nodemanager.resource.cpu-vcores, which control the amount of memory and CPU on each node, both available to both maps and reduces Essentially: YARN has no TaskTrackers, but just generic NodeManagers. Hence, there's no more Map slots and Reduce slots separation. Everything depends on the amount of memory in use/demanded

I developed an auto-call application. The app reads a text file that includes a phone number list and calls for a few second, ends the call and then repeats. My problem is that the app does not send calls after 10~16 hours. I don't know the reason exactly, but I guess that the problem is the CPU usage. My app's CPU usage is almost 50%! How do I reduce CPU usage? Here is part of source code: if(r_count.compareTo("0")!=0) { while(index < repeat_count) { count = 1; time_count = 2; while(count < map.length) { performDial(); //start call reject(); //end call finishActivity(1); TimeDelay("60"); //

I've been reading a nice answer to Difference between reduce and foldLeft/fold in functional programming (particularly Scala and Scala APIs)? provided by samthebest and I am not sure if I understand all the details: According to the answer ( reduce vs foldLeft ): A big big difference (...) is that reduce should be given a commutative monoid, (...) This distinction is very important for Big Data / MPP / distributed computing, and the entire reason why reduce even exists. and Reduce is defined formally as part of the MapReduce paradigm, I am not sure how this two statements combine. Can anyone

For education purposes, I was trying to re-create Underscore.js's _.reduce() method. While I was able to do this in an explicit style using for loops. But this is far from ideal because it mutates the original list that was supplied as an argument, which is dangerous. I also realized that creating such method using functional programming style is harder, since it is not possible to explicitly set i value for looping. // Explicit style var reduce = function(list, iteratee, initial) { if (Array.isArray(list)) { var start; if (arguments.length === 3) { start = initial; for (var i = 0; i < list

I am using following code to resize an image - it all works well and as expected... Resize UIImage the right way I use interpolation quality as kCGInterpolationLow and UIImageJPEGRepresentation(image,0.0) to get the NSData of that image. The problem is that the image size is still a bit high in size at around 100kb. My question is can I reduce it further? The images originate from the iPhone Photo Album and are selected via a imagePickerController . Many thanks, 来源： https://stackoverflow.com/questions/4013871/uiimage-reduce-byte-size

For an associative operation f over the elements of array a , the following relation should hold true: a.reduce(f) should be equivalent to a.reduceRight(f) . Indeed, it does hold true for operations that are both associative and commutative. For example: var a = [1,2,3,4,5,6,7,8,9,0]; alert(a.reduce(add) === a.reduceRight(add)); function add(a, b) { return a + b; } However it doesn't hold true for operations that are associative but not commutative. For example: var a = [[1,2],[3,4],[5,6],[7,8],[9,0]]; alert(equals(a.reduce(concat), a.reduceRight(concat))); function concat(a, b) { return a