用MATLAB的backslash得到的结果比用gradient descent得到的结果差很多，不知道是什么原因 - 未名空间MITBBS历史存档

国际科技财经博客移民网络热点娱乐民生时事公众号

Redian新闻

>未名空间

>Computation - 科学计算

用MATLAB的backslash得到的结果比用gradient descent得到的结果差很多，不知道是什么原因

用MATLAB的backslash得到的结果比用gradient descent得到的结果差很多，不知道是什么原因# Computation - 科学计算

z*e2008-08-02 07:08

1 楼

test a simpl UDP send/receive program on IPv6 (windows).
Following the examples on:
http://msdn.microsoft.com/en-us/library/ms738639(VS.85).aspx
It only receives UDP if it's from the local machine, otherwise nothing.
Not sure why. I already disabled firewall. The machine has 3 NICs, but the
same problem exists on another machine with 1 NIC.
The UDP packets DO arrives on the server machine (I can see them with a sniffer tool), but the recvfrom() just doesn't respond.

e*e2008-08-02 07:08

2 楼

解一个linear equation system （overdetermined system)，用MATLAB的backslash的
结果比用gradient descent （用的neural network)解得的结果差很多。不知道是什么
原因？
查了一下，backslash用least square方法先把overdetermined system的coefficent
matrix变成square matrix，然后用Gaussian elimination。
这种方法为什么比用gradient descent方法得到的结果差很多呢？

T*i2008-08-02 07:08

3 楼

errno是啥？

sniffer tool), but the recvfrom() just doesn't respond.

【在 z***e 的大作中提到】

: test a simpl UDP send/receive program on IPv6 (windows).
: Following the examples on:
: http://msdn.microsoft.com/en-us/library/ms738639(VS.85).aspx
: It only receives UDP if it's from the local machine, otherwise nothing.
: Not sure why. I already disabled firewall. The machine has 3 NICs, but the
: same problem exists on another machine with 1 NIC.
: The UDP packets DO arrives on the server machine (I can see them with a sniffer tool), but the recvfrom() just doesn't respond.

z*e2008-08-02 07:08

4 楼

呃，解决了，的确是firewall，谢谢。