本文简单演示,如何对现有进程进行二维划分,如何获得进程的X和Y坐标. 只有一段程序: #include <mpi.h> #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { int rank,size; int rankX, rankY; int ndims = 2; int dims[2] = {2, 2}; int periods[2] = {0, 0}; int reord
题目链接 Problem Description There is an apple tree in front of Taotao's house. When autumn comes, n apples on the tree ripen, and Taotao will go to pick these apples. When Taotao picks apples, Taotao scans these apples from the first one to the last one
没有join条件导致笛卡尔乘积 学过线性代数的人都知道,笛卡尔乘积通俗的说,就是两个集合中的每一个成员,都与对方集合中的任意一个成员有关联.可以想象,在SQL查询中,如果对两张表join查询而没有join条件时,就会产生笛卡尔乘积.这就是我们的笛卡尔乘积导致的性能问题中最常见的案例:开发人员在写代码时遗漏了join条件. 发生笛卡尔乘积的sql: select sum(project_fj.danjia*project_fj.mianji) from project_fj,orderform w
Nowadays, little haha got a problem from his teacher.His teacher wants to design a big logo for the campus with some circles tangent with each other. And now, here comes the problem. The teacher want to draw the logo on a big plane. You could see the