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可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: We've had a small spark cluster running for a month now that's been successfully executing jobs or let me start up a spark-shell to the cluster. It doesn't matter if I submit a job to the cluster or connect to it using the shell, the error is always the same. root@~]$ $SPARK_HOME/bin/spark-shell Spark assembly has been built with Hive, including Datanucleus jars on classpath 14/11/10 20:43:01 INFO spark.SecurityManager: Changing view acls to: root, 14/11/10 20:43:01 INFO spark.SecurityManager: Changing modify acls to: root, 14/11/10 20:43:01

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Chapter of order property in CSS flexbox says: Absolutely-positioned children of a flex container do not participate in flex layout, but are reordered together with any flex item children. I thought order on absolutely-positioned children of a flex container would place one on another and I tried as following: .container {display: flex} .child1, .child2 {position: absolute} .child1 {background: red} .child2 {background: yellow} <div class="container"> <div class="child1">this is a first</div> <div class="child2">this is an second</div> </div

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: >>> import pandas as pd >>> pd.__version__ '0.16.1' >>> s1 = pd.Series([1, 3, 5], index=list('abc')) >>> s1.iloc(0) <pandas.core.indexing._iLocIndexer object at 0x10ca3f690> I expected the integer 1 to be returned for s1.iloc(0) , but got an _iLocIndexer object instead. What can I do with this object? How do I work with it? 回答1: The solution, due to @JohnE, is to use square brackets [0] instead of (0) with iloc . Some more info after digging through some pandas code. s1.iloc makes iloc look like a method. But it is an attribute and the value

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: From this site which seems to have the most detailed information about catmull-rom splines: http://www.mvps.org/directx/articles/catmull/ it makes mention of needing four points to create the spline. However it does not mention how the points p0 and p3 affect the values between p1 and p2. Another question I have is how would you create continuous splines? Would it be as easy as defining the points p1, p2 to be continuous with p4, p5 by making p4 = p2 (that is assuming we have p0, p1, p2, p3, p4, p5, p6... pN). A more general question is how

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Now a days real time updates are common in most popular sites which have heavy usages. StackExchange Facebook Twitter I'm wondering how do these "real time updates" work? I'm just looking for a general bird's view perspective. I suspect that the JS can't be calling the server every X seconds for an update and then appending that to the . Is a notification sent from the server went to pull more content? Would be great if there is a simple how to article that explains this with a demo? 回答1: Stack Overflow is using Web Sockets for real time

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: When I launch my android app and I try to do a login process using WiFi data, it's all right. But if I launch the app again and I try to to the same process using mobile data, the process still waiting until I get an error. The code is: class AsyncLogin extends AsyncTask< String, String, String > { String username, password; protected void onPreExecute() { pDialog = new ProgressDialog(MainActivity.this); pDialog.setMessage("Login..."); pDialog.setIndeterminate(false); pDialog.setCancelable(false); pDialog.show(); } protected String

pthread_mutex_init()函数用于创建一个互斥量，第一个参数指向互斥量的数据结构pthread_mutex_t的指针，第二个参数是定义互斥量属性的pthread_mutexattr_t结构的指针，他的默认类型是fast。类似于信号量的使用方法， pthread_mutex_lock（）是对互斥量进行锁定操作， pthread_mutex_unlock（）是对互斥量进行解锁操作， pthread_mutex_destroy()的作用是清除互斥量。 演示互斥量的操作方法 #include <stdio.h> #include <unistd.h> #include <pthread.h> #include <string.h> #include <stdlib.h> #include <semaphore.h> void *thread_function(void *arg); pthread_mutex_t work_mutex; //定义互斥量 #define WORK_SIZE 1024 char work_area[WORK_SIZE]; int time_to_exit=1; int main () { int res; pthread_t a_thread; //保存创建线程的返回值 void *thread_result; //结束线程的返回值 res

android 休眠唤醒机制分析(二) ― early_suspend early_suspend 是Android休眠流程的第一阶段即浅度休眠，不会受到wake_lock的阻止，一般用于关闭lcd、tp等设备为运行的应用节约电能。Android的 PowerManagerService 会根据用户的操作情况调整电源状态，如果需要休眠则会调用到HAL层的 set_screen_state() 接口，在 set_screen_state() 中会向 /sys/power/state 节点写入"mem"值让驱动层开始进入休眠流程。 Linux系统支持如下休眠唤醒等级 const char *const pm_states[PM_SUSPEND_MAX] = { #ifdef CONFIG_EARLYSUSPEND [PM_SUSPEND_ON] = "on", #endif [PM_SUSPEND_STANDBY] = "standby", [PM_SUSPEND_MEM] = "mem", }; 但在Android中一般只支持"on"和"mem"，其中"on"为唤醒设备，"mem"为休眠设备。 /sys/power/state 节点的读写操作如下： static ssize_t state_show(struct kobject *kobj, struct kobj

目前Druid集群版本为0.11.0，新版本0.12.1已支持Druid SQL和Redis，考虑到Druid新特性以及性能的提升，因此需要将Druid从0.11.0版本升级到0.12.1版本，下面将对Druid升级步骤做详细的介绍，升级时请严格按照此步骤进行升级，以免出现一些不可预知的问题。 Druid官网 下载druid-0.12.1-bin.tar.gz和mysql-metadata-storage-0.12.1.tar.gz 解压druid-0.12.1-bin.tar.gz [work@druid]$ tar -zxvf druid-0.12.1-bin.tar.gz [work@druid]$ rm -rf druid-0.12.1-bin.tar.gz 解压mysql-metadata-storage-0.12.1.tar.gz [work@druid]$ tar -zxvf mysql-metadata-storage-0.12.1.tar.gz -C druid-0.12.1/extensions/ [work@druid]$ rm -rf mysql-metadata-storage-0.12.1.tar.gz [work@druid druid-0.11.0]$ cd conf/druid/_common [work@druid _common]$ vi

编译驱动时报错： make -C /work/system/linux-2.6.22.6 M= pwd modules make[1]: Entering directory /work/system/linux-2.6.22.6' make[2]: *** No rule to make target /work/driver_test/leds/drv/myleds.c’, needed by /work/driver_test/leds/drv/myleds.o'. Stop. make[1]: *** [_module_/work/driver_test/leds/drv] Error 2 make[1]: Leaving directory /work/system/linux-2.6.22.6’ make: * [all] Error 2 解决办法如下： 1、我的驱动文件名为leds_drv.c，所以编译出来的.o文件名为leds_drv.o 。但是从报错里面可以发现在MakeFile文件里面依赖的竟然是myleds.o,出错的原因就在这里。只需要把MakeFile文件里面的myleds.o改成leds_drv.o即可make成功。 文章来源: 执行make编译驱动文件生成ko驱动文件时报错