i****d
发帖数: 255 | 1 hey,
what is the latex symbols for the summation with a prime? An example is
attached below. I tried \sum_{i=0}^{n} ', but it won't work. If i used \sum_
{i=0}^{n} \prime,
i shall get a big prime.
Thank you! |
|
h*******o
发帖数: 4884 | 2 My opinion
I assume it is a introductory/leading paragraph rather than a detailed
specific aim experiment design.
As a proposal, you dont' have to list the detailed methods in an
introductory paragraph. I would trim it a lot to something like,
To investigate the role of APPLE activation/dysregulation in APPLE
diseases, we propose to use a variety of biochemical, genetical and
analytical assays that summate at the mechanistic role of APPLE in APPLE
disease.
Proceed to expand the |
|
S**********e
发帖数: 1789 | 3 在开玩笑吧。此人是印度人，Texas Tech的，那几篇牛文章是Harvard, 姓一样，名字
不一样。他就2篇文章。
Sensitivity enhancement and matrix effect evaluation during summation of
multiple transition pairs-case studies of clopidogrel and ramiprilat.
Manjunath Swamy J, Kamath N, Radha Shekar AK, Srinivas NR, Kristjansson F.
Biomed Chromatogr. 2010 May;24(5):528-34. doi: 10.1002/bmc.1322.
Lentiviral delivery of short hairpin RNAs protects CD4 T cells from multiple
clades and primary isolates of HIV.
Lee SK, Dykxhoorn DM, Kumar P, Ranjbar S, So... 阅读全帖 |
|
b*******u
发帖数: 62 | 4 i think this problem is documented in literature
check recent literature by Linse P group
the derived Ewald summation for dipole-dipole interaction |
|
w********e
发帖数: 944 | 5 I have to do calculation as (x1^a1)*(x2^a2)...(x4000^a4000) in matlab. xi
falls in [0,1] and the summation of all xi's is 1. Most ai are zeros; for
those greater than zero usually have small integer value, say, 1, 2, 10.
The result of calcluation is always zero. What can I do with it? |
|
h********e
发帖数: 4 | 6 Can anybody tell me a fast and robust algorithm to determine whether a
vector point x is inside a cone formed by a set of vector points {x1, x2, ..
., xn}? x1, x2, ..., xn can be linear dependent. Cone is the linear
summation of {x1, x2, ..., xn} with non-negative coefficients.
A similar question is how to determine whether x is inside the convex hull
formed by {x1, x2, ..., xn}.
Thank you. |
|
b*****e
发帖数: 499 | 7 1. Matlab provides a class 'gmdistribution' for GMM高斯混合模型.
2. If you want to implement by yourself.There some tricks for implementing
this kind of algorithms numerically stable. For example:try to maximize log-
likelihood rather than the likelihood so that 连乘 becomes summation. When
computing the log-likelihood, you may need to subtract the maximal values
and put it back to prevent underflow. |
|
U***t
发帖数: 98 | 8 没有人回答么？呵呵，可能太容易了。。。
自己独立想了一下，也确实很容易，还是自问自答吧，
左边a*(F*b)=>a_{j}e_{j}*(F_{ij}b_{i})e_{j}
这里i=j,而且用了Einstein summation convention
继续推出=>(F_{ji}a_{j})e_{j}*b_{i}e_{i}
=〉(F^{T}*a)*b
结合右边消去b，
F^{T}*a=c
然后就出来了
a=((F^{-1})^{T})*c
总结一下，有向量张量的混合计算常常要用他们的分量来推导。 |
|
c****n
发帖数: 2031 | 9 You mean you solve the semi-discrete equation analytically and then
truncate the summation to obtain a numerical solution? I think that's
only one of the spectral methods.
Anyway, I think we are far away from the original problem right now, hehe. |
|
d*****8
发帖数: 1 | 10 power(1-exp(-power(k/alpha,beta)),phi)*power(q,k)
sum on k from zero to infinity
alpha, beta, phi >0
q<1
Is it possible to get a solution? |
|
B********e
发帖数: 10014 | 11
~~here mush be M'?
the problem is actually :
prove for any vector x
||I-xx'/x'x||_2=1
represent xx' and x'x in form of summation you'll see it |
|
B********e
发帖数: 10014 | 12 why don't you just write down the summation form and the matrix?
let S=sum_1^n (v_i)^2=x'*x, ... ,go ahead
can |
|
h********e
发帖数: 4 | 13 Can anybody tell me a fast and robust algorithm to determine whether a
vector point x is inside a cone formed by a set of vector points {x1, x2, ..
., xn}? x1, x2, ..., xn can be linear dependent. Cone is the linear
summation of {x1, x2, ..., xn} with non-negative coefficients.
A similar question is how to determine whether x is inside the convex hull
formed by {x1, x2, ..., xn}.
Thank you. |
|
I*****o
发帖数: 101 | 14 f_n = \sum\limits_{m=1}^{n} \sum\limits_{i=m-1}^{n-1} f_{mi}
我老板画个图就把求和的 i, m 换了个顺序，还把范围给改了
f_n = \sum\limits_{i=0}^{n-1} \sum\limits_{m=1}^{i-1} f_{mi}
这怎么弄的啊，实在想不出来。。。。 |
|
|
n***p
发帖数: 7668 | 16 不就是把一个矩阵的上三角（包括对角线）的元素全部加起来么？第一个公式
一行一行地加，第二个一列一列地加。 不过第二个公式是错的。应该如下：
f_n = \sum\limits_{i=0}^{n-1} \sum\limits_{m=1}^{i+1} f_{mi} |
|
n***p
发帖数: 7668 | 17 By the way, why didn't you just ask your boss? |
|
I*****o
发帖数: 101 | 18 问了，他说很简单，本科的东西，你再研究研究。。。 |
|
I*****o
发帖数: 101 | 19 哦，对，是i+1，我抄错了。。。
谢谢，数学系的牛。。。
我不是数学系的，咋就看不出来呢。。。 |
|
j******n
发帖数: 271 | 20
Let me try. I got the summation equals:
1/(m+1) * \sum{k=0,m} {exp( y e^{i 2k\pi/(m+1)} + i 2k\pi/(m+1) )}
where i=sqrt(-1) |
|
Q***5
发帖数: 994 | 21 Yes.
Take log of the product part, and notice that log(1-a/i) has the same order
as -a/i, and the summation of which tends to negative infinity. |
|
|
|
|
n*********3
发帖数: 534 | 25 I see A lot of books places say that Euler solved the Basel problem. But
they only show the results, and not how.
Can anyone show how?
Lookacar and others?
"Notably, Euler directly proved the power series expansions for e and the
inverse tangent function. (Indirect proof via the inverse power series
technique was given by Newton and Leibniz between 1670 and 1680.) His daring
use of power series enabled him to solve the famous Basel problem in 1735 (
he provided a more elaborate argument in 1741)... 阅读全帖 |
|
v****x
发帖数: 498 | 26
~~~~~~~~~~~~~~~~~~~~~~ this is the system you
want to model
~~~~~~~~~~~~~~~~this is for k-space sampling,
which is used for integration (actually summation)
, |
|
c*******9
发帖数: 9032 | 27 Summation of Tesla's Dynamic Theory of Gravity
An excerpt from: Occult Ether Physics
by William R. Lyne
From: Don Allen
d**[email protected]
According to Tesla's lecture prepared for the Institute of Immigrant Welfare
(May. 12, 1938), his "Dynamic Theory of Gravity" was one of two far
reaching discoveries, which he "...worked out in all details", in the years
1893 and 1894. The 1938 lecture was less than five years before his death.
More complete statements concerning these discoveries can ... 阅读全帖 |
|
n********e
发帖数: 2 | 28 Just had a question when i read material in 精华区 regarding 硬币游戏的
Stopping Time解法(i attached to solution for convience).
Why the the event of A[n[k]] have no intersection? I think they do have
intersections. so the total probability can not be a summation of the
probability of each event.
Thanks |
|
b******y
发帖数: 139 | 29 A colleague asked me this question today:
Prove that all two digit even numbers (between 10 and 98) can be expressed
the summation of two primes. |
|
b***k
发帖数: 2673 | 30 ☆─────────────────────────────────────☆
idontknow (不要问我到哪里去) 于 (Mon Oct 8 23:12:09 2007) 提到:
You are given an array of integer of size N (A[0],A[1],A[2],...A,[N-1])
containing both negative and non-negative integers. Design an efficient
algorithm to find the sub sequence A[i],A[i+1],A[i+2]...,A[j] having the
maximum summation (A[i]+A[i+1]+A[i+2] + ...+A[j] have the highest sum). What
is the complexity of your algorithm?
－－－
大家讨论一下。
☆─────────────────────────────────────☆
robustzgy (浪迹天涯 |
|
b***k
发帖数: 2673 | 31 ☆─────────────────────────────────────☆
iamfine (iamfine) 于 (Thu Jun 26 17:17:59 2008) 提到:
I am looking at Haug's book (pp.196-199). In the case we are inside the
average period (m>0), the code adjusts the strike but does not make an
adjustment to the total number of averaging points left (n-m in stead of n),
which makes time between points (dt) smaller and the summations are among
more points. Is this just my misunderstanding or is there some other reasons?
Thanks,
☆─────────────────────── |
|
f*****s
发帖数: 141 | 32 Summation of normal is still a normal |
|
o****e
发帖数: 80 | 33 恕我愚笨，哪有summation?
用 itosym 一步就出结果了阿 |
|
k**k
发帖数: 61 | 34 You are exactly right. I accidentally dropped the summation term. Could you
please explain why this yields the correct answer? Note that "a", the 95%
VaR varies under each weight scenario. The algorithm I saw starts with a
relatively arbitrage value of "a". Under that objective function, it returns
the same optimal weight each time.
Thoughts? |
|
a******u
发帖数: 66 | 35 3 questions asked today:
1. Random walk. Starting from 0, 1/2 probability of +1, 1/2 probability of -
1. What is the expectation after n steps? What is the variance?
2. Given an array of n numbers. Suppose we know it is from N(0,1). How do
you convince yourself it is (or not) N(0,1)?
3. Given an array of n numbers. How to find a subarray of maximum summation? |
|
a*******1
发帖数: 1554 | 36 Thank you for sharing!
-
summation? |
|
t*******y
发帖数: 637 | 37 2 画histogram？
3 kadan
-
summation? |
|
L******2
发帖数: 274 | 38 For #3, I think the question is to find the contiguous subarray with maximum
summation. |
|
z****g
发帖数: 1978 | 39 Also, you may need to check the basic analytically form of Ito integral. I
remember the definition is quite loose as it does not require the summation
converges on 'arbitrary' partition of t, in this sense you can choose a sub-
sequence of partition that will converge almost everywhere. Also, I remember
the integral itself converges only in terms of measure.
|
|
d*e
发帖数: 843 | 40 多谢，我再试试，我相信是对的，但也有可能本来就不成立
有谁能想到简单的证明请告诉我啊
summation
sub-
remember |
|
p********6
发帖数: 1802 | 41 The summation of two normal is normal no matter they are independent or not. |
|
p********6
发帖数: 1802 | 42 But if the correlation of X Y is const, then X Y can be represented by two
independent normal, then the summation seems to be normal... |
|
l******i
发帖数: 1404 | 43 no
xiaojiya说的是(X,Y)如果jointly normal，
那么任意linear combination of X and Y must be normal，
自然而然summation就是normal的，
这是exactly jointly normal的定义，和你说的correlation一点关系也没有。 |
|
L**********u
发帖数: 194 | 44 1/dW_t^2-t is a martingale and the integrand should be interpreted as
2/d \sum_{s=1}^d W_s dW_s.
In Riemann Geometry, we always omit the sum notation by Einstein summation
convention |
|
Q***5
发帖数: 994 | 45 The summation of two Poisson process is still Poisson, with intensity 2a.
Let x be the expected waiting time, we have the equation:
x = int_0^b 2a exp(-2at) *(x+t) dt
Solve for x.
min |
|
r****y
发帖数: 1437 | 46
Define Hamilton function
H(p, q, t)=Summation(p(i) d(q(i))/dt)-L
d p(i)/dt = - partial(H)/partial(q(i))
d q(i)/dt = partial(H)/partial(p(i))
in Poisson bracket
d p(i)/dt =[p(i), H]
d q(i)/dt =[q(i), H] |
|
s***e
发帖数: 911 | 47
Oh...
Div(p*q)=d_i(p*q_i)=p*d_i(q_i)+(d_i(p))*q_i=p*div(q)+grad(p) \dot q
Where p is a scalar, q is a vector, and d_i is the derivative respect to
the i-th coordinate. Repeated index means summation.
We have already express q by derivative of x(a,t), so replace p by \rho u
get the result. |
|
r****y
发帖数: 1437 | 48
For an integral
\int{a, b}{W(x)f(x)}
You can scale it to \int{-1, 1},
when W(x) = 1/sqrt(1-x^2), given N, we can calculate N points
in [-1, 1], get a set like this
x1, w1
x2, w2
...
xi, wi
...
And your integration can be approximated by
summation{i=1, N}{wi*f(xi)}
|
|
r****y
发帖数: 1437 | 49
我想这道题要是没解析解那么思路该如下
做代换，凑成积分函数
f(t) = g(t)/(1-t^2), where t is from -1 to +1
Then
f(t) \= summation(g(ei)w(ei))
where ei is the root for Chebychev polynomials,
for n-order Chebychev,
ei = cos((pi/2)(2i+1)/(n+1)), where i = 0, 1, 2, ...n
嘿嘿纯粹学数值分析学多了根本不想解析解的结果． |
|
s***e
发帖数: 3 | 50 How about expand Exp(-v*v) also. Try this:
Exp(a v D_v) = Sum(a v D_v)^n
Exp(-v*v) = Sum(-v*v)^m
Then time the two series together. If n>m, the element is 0; else you can
connect the upper limit of summation on n with m.
Not sure what you are really expecting. But, that might lead you to some luck.
Good luck. |
|
