s*******h
发帖数: 2148 | 1 好玩
Your inaccuracy by category:
Parallelogram 2.8 5.8 3.2
Midpoint 3.2 5.0 6.7
Bisect angle 2.4 2.2 3.9
Triangle center 5.8 4.5 2.8
Circle center 5.1 2.2 2.2
Right angle 2.4 1.0 7.0
Convergence 4.2 6.1 2.8 |
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s*******h
发帖数: 2148 | 2 2nd time:
Your inaccuracy by category:
Parallelogram 3.0 6.4 5.1
Midpoint 2.2 4.1 1.4
Bisect angle 0.6 1.7 5.8
Triangle center 2.7 5.0 5.6
Circle center 3.6 5.0 5.8
Right angle 5.0 2.5 0.7
Convergence 12.5 1.4 1.0
Average error: 3.86 (lower is better)
same score...ft |
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s*******h
发帖数: 2148 | 3 没前途了
Your inaccuracy by category:
Parallelogram 3.0 3.0 4.1
Midpoint 5.0 5.4 1.4
Bisect angle 1.6 6.2 0.3
Triangle center 2.6 3.5 1.6
Circle center 3.0 3.6 6.4
Right angle 3.8 2.5 4.2
Convergence 2.0 2.8 2.8
Average error: 3.28 (lower is better) |
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s******e
发帖数: 493 | 4 Used to write monte carlo simulation running tens millions of loop times.
Here was what I did. it might not be the best approach.
1.carefully check the logics for culprit. if failed,
2.then run the loop a couple of times and check all the major lines for
possible offenders. if still failed,
3.use bisect method to cut the number of loop times for each check. very
tedious... if still failed.
4.leave it alone and pray... |
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S*A
发帖数: 7142 | 5 应该没有问题的。glibc 几乎是一直向下兼容的。我还没有听说这个
interface 会让旧的 glibc 不能跑的变化。这就是 kernel 重来不
改变 system call API 的原因。例如新的 mmap 是加一个 mmap2 的
system call. 然后内部把旧的 mmap system call 翻译到等价的 mmap2
上面去。不会直接换 mmap system call 的。
kernel developer 非常注意不干这种 break glibc 向下兼容的事情的。
因为就 kernel developer 自己就很不方便，你要 bisect 一个 kernel
regression 还要换 glibc？ Linus 那关肯定就过不了。
有其他的东西可能会导致换新 kernel 跑不起来，例如 udev, modprobe
这些东西。但是你什么时候注意到新 kernel 让旧的 libc 跑不起来的？
我是没有见过。 |
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p***o
发帖数: 1252 | 6 i believe std::binary_search uses std::advance and std::distance
to calculate bisection, which have specializations for random
iterators. |
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F******k
发帖数: 197 | 7 Try tortoise git，similar nice GUI for svn.
Git的真正问题是regression发生时，对于不同开发者的checkin, 很难迅速用bisect定
位。
这恐怕是分布式系统难以绕开的问题。 |
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F******k
发帖数: 197 | 8 Try tortoise git，similar nice GUI for svn.
Git的真正问题是regression发生时，对于不同开发者的checkin, 很难迅速用bisect定
位。
这恐怕是分布式系统难以绕开的问题。 |
|
g****t
发帖数: 31659 | 9 就算没听说过牛顿法,
你没听说过bisection吗?
80%上过数值计算课的本科生都能. |
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a*****g
发帖数: 19398 | 10 #!/usr/bin/env pike
// legal.pike - Count the number of legal go boards.
// Copyright 2005 by Gunnar Farneb?ck
// [email protected]
/* */
//
// You are free to do whatever you want with this code.
//
//
// This program computes the number of legal go board configurations
// for a rectangular board of a given size. It is efficient enough to
// handle boards up to 8x8 within minutes and up to 11x11 in less than
// 24 hours (on a fast computer). For rectangular boa... 阅读全帖 |
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h***t
发帖数: 2540 | 11 Newton Method
Bisection Method
Secant Method
Steffensen's Method |
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c**i
发帖数: 6973 | 12 【 以下文字转载自 USANews 讨论区 】
发信人: choi (choi), 信区: USANews
标 题: Test Your Mathematics Skill
发信站: BBS 未名空间站 (Thu Apr 15 17:45:47 2010, 美东)
Do not peek at the answer at the lower right corner, which in the print of
report below is printed upside down. Here is hte question.
http://www.nytimes.com/imagepages/2010/04/15/us/15math_CA0.html
Note:
(a) parallelogram (n): "a quadrilateral with opposite sides parallel and
equal"
* quadrilateral (n): "a polygon of four sides"
(b) bisect (vt): "to divide into tw |
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F*******n
发帖数: 8 | 13 The following is copied from p.622 of Siu's 1988 Annals paper "The Existence
of Kahler-Einstein...". Siu is really angry at Tian's plagiarism.
Added after submission of paper. I presented the results and methods of this
paper in the Geometry and Analysis Conference at Columbia University in
April, 1986. G. Tian in August, 1986 wrote a paper "On Kihler-Einstein
metrics on certain Kihler manifolds with cl(M) > 0" (Invent. Math. 89 (1987)
, 225-246) in which he constructed Kdhler-Einstein metrics f... 阅读全帖 |
|
v*********n
发帖数: 573 | 14 田院士曰：“窃idea不算偷”。
The following is copied from p.622 of Siu's 1988 Annals paper "The Existence
of Kahler-Einstein...". Siu is really angry at Tian's plagiarism.
Added after submission of paper. I presented the results and methods of this
paper in the Geometry and Analysis Conference at Columbia University in
April, 1986. G. Tian in August, 1986 wrote a paper "On Kihler-Einstein
metrics on certain Kihler manifolds with cl(M) > 0" (Invent. Math. 89 (1987)
, 225-246) in which he constructed Kdhler-... 阅读全帖 |
|
g****t
发帖数: 31659 | 15 教授不知道用newton法求x^14=P的根吗？还泰勒展开呢...
Bisection其实更适合心算。
这个太标题党了。
不过周伟确实挺牛的。看网上的贴图，那个教授是用泰勒展开在算。但周伟应该不是这
样。
我想了半天，猜他是背了素数的对数表，先把大数进行素数分解，然后心算得出的结果
，确实很牛。
ps:看后来梁冬忏悔，我也有同感。小学时班上也有一个“傻子”，经常被班上几个坏
孩子欺负，我们其他的也看热闹“乐在其中”。后来我们升级了，那个同学还继续上4
年纪。 看完节目我问我妈那个同学还在小区里吗？我妈说已经好些年没见过了，估计
可能都不在了，唉。国内对残疾人士的照顾差太远了。 |
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a*****g
发帖数: 19398 | 16 【 以下文字转载自 Programming 讨论区 】
发信人: ananpig (●○ 围棋数学一把抓的安安猪), 信区: Programming
标 题: 计算围棋棋盘合法图案的源代码
发信站: BBS 未名空间站 (Fri Jan 22 10:39:02 2016, 美东)
#!/usr/bin/env pike
// legal.pike - Count the number of legal go boards.
// Copyright 2005 by Gunnar Farneb?ck
// [email protected]
/* */
//
// You are free to do whatever you want with this code.
//
//
// This program computes the number of legal go board configurations
// for a rectangular board of a given size. It is ef... 阅读全帖 |
|
B*********h
发帖数: 800 | 17 ☆─────────────────────────────────────☆
zhuzhu111 (猪猪) 于 (Thu Oct 12 13:42:19 2006) 提到:
how to get the numerical answer of sqrt(37)=6.08276....
(怎么用代数方法解37开平方)
thanks.
☆─────────────────────────────────────☆
emacs (VC) 于 (Thu Oct 12 17:00:52 2006) 提到:
I guess the general method should be Newton-Raphson.
sqrt is a common question being asked in interview, think about sqrt(2) and
sqrt(3).
Another direct method is trial & error, similar to bisection method....
☆─────────────────────────── |
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z****u
发帖数: 185 | 18 probably no closed form.
But it does not matter, you can use some numerical algorithm such as Newton or bisection to find the solution. Since vanilla option price is a monotonic function of implied vol, the implementation can be rather straightforward. |
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m****e
发帖数: 7 | 19 yes, thanks. but I am just wondering how it was actually computed...or
implemented. how does bloomberg compute it? also using bisection numerical
method? or some smarter method...? |
|
w*****e
发帖数: 158 | 20 【 以下文字转载自 JobHunting 讨论区 】
发信人: woommle (mm), 信区: JobHunting
标 题: 两道算法题
发信站: BBS 未名空间站 (Mon Sep 27 16:56:25 2010, 美东)
1) given the whole range of 6 digit numbers, design an algorithm which
prints out numbers which have the sum of the right 3 digits equal the left
3 digits? like 123600, 345435 etc.
2）design an algorithm to find square_root of a float? how do you make the
algorithm efficient?
第一题：除了每个数检验之外，还有什么更快得方法吗？
第二题：貌似可以用bisection method 或者 Newton method， Newton method 收敛的
更快
一些。有什么地方需要注意或者 |
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l*******l
发帖数: 248 | 21 要么bisection，要么secent，感觉讨论这个没什么意义 |
|
y**i
发帖数: 13 | 22 @zouzou:
thanks for comments! it makes sense.
my first thinking is to use finite-difference to price American Option and
use bisection method to find the root.
what is the most efficient or practical way to do this in terms of choosing
different solver and root finding method?
@qxx:
I don't know much about flat vol.hope some one will comment on this |
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w**n
发帖数: 88 | 23 Are you sure you are using "Pure Newton Mehtod", becuause if you mixed
the bisection with newton method , there will be no problem for any solvable
case.
Here is the proof that f(x)=x^(1/3 ) is not solvable with newton's method
x[n+1]=x[n]-f(x[n])/f'(x[n])
=x[n]-( x[n]^(1/3) )/ ( (1/3)*x[n]^(-2/3) )
=x[n]-3x[n]
=-2x[n]
This implies that | x[n+1]-x[n] |=3x[n]
Hence Newton's Method fails.
|
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r****y
发帖数: 1437 | 24 with today's computation power, solving this in even the most brutal
-force way would not take too much time.
E.g. grid serch
for theta = -pi/2 to pi/2
for phi = 0 to 2*pi
...
Or a little bit smarter, use bisecting, since the distance from p0 (
or p1) is piecewise montonous increasing/decreasing function.
|
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a***a
发帖数: 12425 | 25 【珍稀动物】萌萌大美瞳---超濒危的绒哆倭丛猴
前两天看到的一个关于世界二十五种最濒危的灵长动物的帖子，看到第一个猴子的图片
一下子就被吸引了。它有一对扇风耳，一双滚圆的眼睛，一只可爱的鼻子，一条长长的
刷子似的大尾巴，双手双脚紧紧地抓在一个树枝上面。这种猴子名叫Rondo Dwarf Gala
go (Galagoides Rondoensis)，在网上查了一下，中文翻成了一个很拗口的名字：绒哆
倭丛猴。
绒哆倭丛猴是一种体重仅两盎司（六十克）的小型物种，属于灵长目原猴亚目，和狐猴
、懒猴、眼镜猴等萌物们亲缘关系不远。直到一九九六年人们才知道这类物种的存在，
并从那时起把它们视为丛猴种类中最小的一种。如今绒哆倭丛猴已经从濒危类变为极度
濒危类动物。
绒哆倭丛猴的大眼睛和大耳朵不单单是用来卖萌，主要是用于在夜间活动，吃昆虫和果
实，而白天它们就会搭一个窝在树上睡觉。绒哆倭丛猴居住在非洲大陆坦桑尼亚海岸的
一些旱生森林中，它们的家并不需要多大的地方。尽管有些这类森林是在国家公园的范
围内，然而，人类的开荒活动，不管是为了种田、还是获得木材和木炭，让它们的小小
家园变得支离破碎、狭窄不堪。... 阅读全帖 |
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y***g
发帖数: 10422 | 26 CV 侧面安全性超烂没错。CV 是 90 年代设计的，一直没大改。正常。
CVPI 侧面撞树后的结果，强吧：
A Santa Maria police officer hit a tree Sunday morning. But! The way it
looks the car is just phenomenal. According to the local Police Chief, is
the “worst accident he’s seen in 35 years.”
Officer Damon Badnell was responding to an officer involved in a foot
pursuit of a burglary suspect when he lost control of his vehicle on a
slippery road. The momentum wrapped the vehicle around the tree, nearly
bisecting the Ford Crown Victoria.
That of... 阅读全帖 |
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p*********e
发帖数: 32207 | 27 看了一下wiki的介绍
"
Thompson coupling[edit]
Thompson coupling from U.S. Patent 7,442,126. Note: drawing on the right
omits certain components in order to illustrate the control yoke's spherical
pantograph.
The Thompson constant velocity joint (TCVJ), also known as a Thompson
coupling, assembles two cardan joints within each other to eliminate the
intermediate shaft. A control yoke is added to keep the input and output
shafts aligned. The control yoke uses a spherical pantograph scissor
mechanism to bi... 阅读全帖 |
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