b******h
发帖数: 71 | 1 我总觉得用mathematica或者matlab这类软件解微分方程速度很慢。
是不是还是用C++来得快些。
至于这些Options的意义，我觉得你找一本数值分析的书看其中的
Runge-Kutta方法及变步长法应该就能知道它们的意思。 |
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b**n
发帖数: 289 | 2 我想解两个Ito Stochastic Differential Equations，但最简单的Euler方法不行。听
说了一种Stochastic Runge-Kutta方法，不知道哪一位有没有相关的经验。因为我
GOOGLE了一下，没有GOOGLE到。图书馆里原本有一本NUMERICAL METHODS FOR SDE的，
但被借出了。请教，多谢。 |
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O******e
发帖数: 734 | 3 y'(x) = Q(x)
Q'(x) = P(x)
Solve them as a coupled set of first-order ODEs.
Runge-Kutta as suggested by sunocean is a possible method. |
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l*********i
发帖数: 483 | 4 用GSL的adaptive Runge-Kutta routine数值解出了f(x)在x=0到1的数值，
如果想要求解g(f(x),x)在区间x=0到1之间的积分，有什么现成的C/C++ routine可以
用么？因为最初f(x)是用adaptive的routine求解的，所以x的步长并不是一个
固定的值，所以一般的Newton-Cotes的库没法直接用。哪位大侠指点一下？ |
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c*******v
发帖数: 2599 | 5 Fourier,Chebyshev等等也都有runge现象，Gibbs现象等问题。 |
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Q******g
发帖数: 607 | 6 tried Mathematica NDSolve?
most time, it's good enough. |
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l*********i
发帖数: 483 | 7 因为是要嵌入到一个monte carlo程序里去的，如果用NDsolve的话不够快。 |
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Q******g
发帖数: 607 | 8 how about matlab then?
ppl said it's easy to combine with C code. |
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l******s
发帖数: 82 | 9 1914年夏，第一次世界大战爆发，8月14日，德国对法国宣战
Courant马上应征入伍，在战争开始的几天，Gottingen大学
的应用数学家Runge经常在他的花园里激动地走来走去，他告
诉人们，他的两个还不算大的孩子应该送到部队里去，但是让
已经证明了有能力的Courant也去冒生命危险就太愚蠢了，受
到狂热的战争情绪的感染，在Courant的日记中随处可见：
（听到远方炮火的声音）Courant再三写道“要是我在那里多
好”
（Courant所在的连被命令保护后方的一个火车车站）Courant
不情愿的写道“我们不得不在这个地方呆着，填饱自己的肚子”
1914年11月1日，Courant高烧被送往附近的村子，“恨不得马
上回到前线”
（和Lohse)“我们在战壕中坐了一会儿，谈起了Gottingen...
直到一颗炸开的手榴弹掀起一块石头打掉了我的头盔，并把我手
中的枪也打掉了”
1915年清晨的行军中，Courant预感到一颗子弹似乎等待着他，
使他惊讶的是这令他更加平静，这时出现了一列英国步兵，
Courant突然感到他的右半身受到猛烈一击，一颗子弹射入Courant
胃部 |
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l*********i
发帖数: 483 | 10 【 以下文字转载自 Computation 讨论区 】
发信人: lamborghini (隐形汽车Reventon), 信区: Computation
标 题: 问个数值积分的问题
发信站: BBS 未名空间站 (Sun Feb 17 17:42:52 2008), 转信
用GSL的adaptive Runge-Kutta routine数值解出了f(x)在x=0到1的数值，
如果想要求解g(f(x),x)在区间x=0到1之间的积分，有什么现成的C/C++ routine可以
用么？因为最初f(x)是用adaptive的routine求解的，所以x的步长并不是一个
固定的值，所以一般的Newton-Cotes的库没法直接用。哪位大侠指点一下？ |
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s*********n
发帖数: 18 | 11 方程中有一函数依赖于方程的解。
我将这两个联立的二阶常微分方程化为了四个一阶常微分方程，然后用RUNGE-KUTTA 方法
进行
积分，但是解在几个循环后变趋向与无穷。SHOOTING METHOD 好象作用不明星。
谢谢。 |
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s*********n
发帖数: 18 | 12 谢谢howell (Beaver)。
我没说清楚，对不起。这是两个联立的ODE。我重新叙述一遍。
方程中有一函数依赖于方程的解。
我将这两个联立的二阶ODE微分方程化为了四个一阶微分方程，然后用RUNGE-KUTTA 方法
进行积分，但是解在几个循环后变趋向与无穷。SHOOTING METHOD 因为需要同时调整两个
斜率，算了很长时间也没结果。
谢谢。
进行 |
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x******i
发帖数: 3022 | 13
当年学曾老的课，印象最深的就是小玻尔、
Runge-Lenz矢量，和压缩态。
曾老上课的时候，动不动就要眉飞色舞的
回忆一下当年在哥本哈根和小玻尔讨论物
理的时光。
比如某次和小玻尔讨论“二次量子化”。曾老
说，所谓粒子从A运动到B，就是在A点消灭
一个粒子，再在B点产生一个粒子。该观点
被小玻大加赞赏。曾老非常得意。
当年俺们在座的同学都是土人，既没去过
哥本哈根，也没听说过二次量子化。当场
对曾老崇拜不已。 |
|
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f**n
发帖数: 401 | 15 How to find out the time when x(t) hit \theta, in which the
dynamics of x(t) is given by the following ODE:
dx(t)/dt=f(t)-cx(t),x(0)=0
and \theta is a paramter.
我现在已经知道用Runge-Kutta法可以解ODE,但是对于我上面的问题，有没有特定的
方法呢？
thx&bow! |
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e****t
发帖数: 766 | 16 离开学校发现看paper 真难， 哪位能帮忙下一下这两片papers
Statistical inference on censored data for targeted clinical trials under
enrichment design
Chen-Fang Chen1,†, Jr-Rung Lin3,† andJen-Pei Liu1,2,4,*
Pharmaceutical Statistics
Volume 12, Issue 3, pages 165–173, May/June 2013
Inference on treatment effects for targeted clinical trials under enrichment
design.
Liu JP1, Lin JR, Chow SC.
Pharm Stat. 2009 Oct-Dec;8(4):356-70. doi: 10.1002/pst.364.
有包子， 多谢先。 |
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m***y
发帖数: 254 | 17 第二项最后的机会(Category 2 Last Chance to See)
Junior Winner: Hide and Seek by Samuel Runge |
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p*********y
发帖数: 2741 | 18 90%都是白人。。。。。
FROM： http://www.racismreview.com/blog/
In an article entitled “Why So Few Asians are College President,” Dr.
Santa J. Ono, President of the University of Cincinnati, indicates that he
finds himself among a very small group of Asian American leaders in higher
education: only 1.5 percent of college and university presidents are Asian
American and 3.4 percent are administrators in higher education. By contrast
, Hispanics comprise 3.8 percent of presidents and African Americans hold 5... 阅读全帖 |
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w****1
发帖数: 24 | 19 【 以下文字转载自 AnthroLing 讨论区 】
发信人: kyotosizumot (....), 信区: AnthroLing
标 题: 刘正教授论文《給臺灣讀者：國立彰化師範大學教授胡瀚平長期抄襲剽竊》
发信站: BBS 未名空间站 (Thu Oct 20 16:10:09 2016, 美东)
給臺灣讀者：國立彰化師範大學教授胡瀚平長期抄襲剽竊
劉 正
臺灣教育部領導 暨
國立彰化師範大學校長郭豔光教授（[email protected]/* */）
副校長李清和教授（[email protected]/* */）
副校長陳明飛教授（[email protected]/* */）
國文學系系主任、臺灣文學研究所所長王年雙教授（[email protected]/* */）
您好！
本人是大陸前 武漢大學、中國人民大學、華東師範大學教授、日本國大阪市立大學文
學博士、日本國京都大學博士後研究員。現旅居美國，為美國漢納國際作家協會副會長。
今日在網路上和刊物上驚訝地發現貴大學國文學系暨臺灣文學研究所教授胡瀚平長期抄
襲我的論著... 阅读全帖 |
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w*******y
发帖数: 60932 | 20 That's right $9.99!! Posted on another thread of the price drop from179.99
to 99.99. Thought to try the combined Donkey Kong/Epic Mickey 50% off to get
it to 49.99 (btw this works for the 360/Ps3 black ops deals online).
Scanned donkey kong first then the super bundle...and it rung out to 59.98
for both pretax.
Receipt looks like this:
Donkey Kong Wii game promo 49.99-0.00
Wii GuitarHero Warrior Band Bundle
Wii game promo 179.99-90.00 (took 50% here)
$80 off select items 89.99-80
Price 9.99!!!
S... 阅读全帖 |
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w*******y
发帖数: 60932 | 21 Here is a link to the same item on Amazon:
http://www.amazon.com/Akro-Mils-66486-Plastic-Attached-Sandston
$26. I cannot find a staples link but their normal price is $15.
This is extremely YMMV. Other Staples may not have them. My cashier may
have not rung it up right. etc.
Here is the story.
I was perusing the aisle at staples and saw some wing lid plastic boxes on
clearance for half price. Normally, about $15; so, big yellow clearance
sheet said $7.49. I thought, "not bad for $7.50. I... 阅读全帖 |
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w*******y
发帖数: 60932 | 22 Target has an Xbox 360 Wireless controller $39 - $10 coupon + tax. In-store
only.
Coupon:
Link:
http://coupons.target.com/electronics-coupons
then look for and print this coupon
To put this deal in perspective, Meijer and Toys R Us both had this price
for this control on Black Friday and they ran out quickly. Even the guy at
Target who rung me up did a double-take.
The Target in my area had at least another 5 controller left.
|
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g******y
发帖数: 2517 | 23 Kidde KL-2S Two-Story Fire Escape Ladder with Anti-Slip Rungs, 13-Foot, 折扣
45%, 只要$35.97
http://amzn.to/v5kZE0 |
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w*******y
发帖数: 60932 | 25 Stopped into academy today to take a look at what they had on clearance. I
came across the Allied Forces Smith and Wesson 9mm Disaster Kit tagged at $
379.88. Once I decided to pull the trigger and cleared background check, it
was a pleasant suprise when it rung up for $358.88!! Out the door price
was $388.49. The Smith and Wesson Sigma 9VE 9mm w/2 hi capacity mags has
sold for $259 after a $50 rebate in the past. This allied forces kit has
sold for as high as $599. Although this may not be... 阅读全帖 |
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w*******y
发帖数: 60932 | 26 The Epson Workforce 635 is on clearance @ staples. I saw one marked on
clearance for $160...took it to the register and it rung up $33.50. The csr
tried to tell me he couldn't sell it to me, then a few other csrs walked up,
tried to adjust the price higher and tried to make me get a 3 year
protection plan. The computer wouldn't let them mark up the price so they
let me have it for $33.50. The customer in front of me handed me a 15% off $
40 coupon, so I got a couple filler items and laughed my w... 阅读全帖 |
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w*******y
发帖数: 60932 | 27 Make More, Worry Less: Secrets from 18 Extraordinary People Who Created a
Bigger Income and a Better Life [Free today only Kindle eBook]
Kindle Price: $0.00
You Save: $24.99 (100%)
Length: 277 pages
Book Description
This is the eBook version of the printed book.
"These principles will not only help you sleep at night, they're steroids
for your paycheck. This book is a can't miss if you want economic freedom
without having to start your own business!"
- Barbara Babbit Kaufman, Founder and Former... 阅读全帖 |
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e***e
发帖数: 3872 | 28 What Is Enlightenment? (Was ist Aufkl?rung?)
Michel Foucault 1984
Today when a periodical asks its readers a question, it does so in
order to collect opinions on some subject about which everyone has an
opinion already;there is not much likelihood of learning anything new. In
the eighteenth century, editors preferred to question the public on
problems that did not yet have solutions. I don't know whether or not that
practice was more effective; it was unquestionably more ente |
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