转载自: http://blog.csdn.net/txwh0820/article/details/46392293 矩阵的迹求导法则 1. 复杂矩阵问题求导方法:可以从小到大,从scalar到vector再到matrix 2. x is a column vector, A is a matrix d(A∗x)/dx=A d(xT∗A)/dxT=A d(xT∗A)/dx=AT d(xT∗A∗x)/dx=xT(AT+A) 3. Practice: 4. 矩阵求导计算法则 求导公式(撇号为…
cr:http://blog.csdn.net/txwh0820/article/details/46392293 一.矩阵的迹求导法则 1. 复杂矩阵问题求导方法:可以从小到大,从scalar到vector再到matrix 2. x is a column vector, A is a matrix d(A∗x)/dx=A d(xT∗A)/dxT=A d(xT∗A)/dx=AT d(xT∗A∗x)/dx=xT(AT+A) 3. Practice: 4. 矩阵求导计算法则 求导公式(撇号为…
# coding:utf-8 from __future__ import absolute_import from __future__ import unicode_literals from __future__ import print_function from __future__ import division import tensorflow as tf x = tf.placeholder(dtype=tf.float32) y = tf.placeholder(dtype=…
F. Four Divisors 题目连接: http://www.codeforces.com/contest/665/problem/F Description If an integer a is divisible by another integer b, then b is called the divisor of a. For example: 12 has positive 6 divisors. They are 1, 2, 3, 4, 6 and 12. Let's def…
1.矩阵相加 两个同型矩阵做加法,就是对应的元素相加. #include<iostream> using namespace std; int main(){ int a[3][3]={{1,2,3},{6,5,4},{4,3,2}}; int b[3][3]={{4,3,2},{6,5,4},{1,2,3}}; int c[3][3]={0,0,0,0,0,0,0,0,0}; int i,j; cout<<"Array A:"<<endl; for…
代码: #include<cstdio> #include<cstring> #define N 200000 using namespace std; long long f[N+5]; long long s[N+5]; int main() { s[0]=0; for(int i=1;i<=N;i++) { for(int j=1;j*i<=N;j++) { f[j*i]+=i; } } for(int i=1;i<=N;i++) { s[i]=s[i-1]…
DescriptionProblems involving the computation of exact values of very large magnitude and precision are common. For example, the computation of the national debt is a taxing experience for many computer systems. This problem requires that you write a…
今天推导公式,发现居然有对矩阵的求导,狂汗--完全不会.不过还好网上有人总结了.吼吼,赶紧搬过来收藏备份. 基本公式:Y = A * X --> DY/DX = A'Y = X * A --> DY/DX = AY = A' * X * B --> DY/DX = A * B'Y = A' * X' * B --> DY/DX = B * A' 1. 矩阵Y对标量x求导: 相当于每个元素求导数后转置一下,注意M×N矩阵求导后变成N×M了 Y = [y(ij)] --> dY/…
