N***m
发帖数: 4460 | 1 PC linux都搞过。
我都是比较大的dense matrices，存下来至少O(G)。
~200M肯定不是matlab本身的问题。 |
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n**f
发帖数: 121 | 2 Depending on how big/sparse the matrice are, and how frequently you have to
solve this, you may want to try LU or SVD using numerical recipe. |
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n**f
发帖数: 121 | 3 how big are your matrices? |
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p**o
发帖数: 3409 | 4 Matlab links against MKL (for dense matrices),
which is written in Fortran. |
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t********n
发帖数: 611 | 5 Can't run this Gauss elimination program. Got error message : not enough
input arguments.
function x = gauss(A,B)
%The sizes of matrices A,B are supposed to be NA x NA and NA x NB.
%This function solves Ax = B by Gauss elimination algorithm.
NA = size(A,2); [NB1,NB] = size(B);
if NB1 ~= NA, error(’A and B must have compatible dimensions’); end
N = NA + NB; AB = [A(1:NA,1:NA) B(1:NA,1:NB)]; % Augmented matrix
epss = eps*ones(NA,1);
for k = 1:NA
%Scaled Partial Pivoting at AB(k,k) by Eq.(2.2.... 阅读全帖 |
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c******o
发帖数: 1277 | 6 有一次一个bug, chef 的 cpan cookbook 在mongodb 建了无数的testdbxxxxx
正好我们每个db建6个custom matrics, 两天就多花了5k多，还好amazon最后给我们免了
。 |
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T*******n
发帖数: 493 | 7 I don't understand your question. After taking out the spurious
\right] from your code, I get one (not three) equations. The
matrices are all one column and three rows. Do you want
three columns and one row? |
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T*******n
发帖数: 493 | 8 \sum, \max, \min, \int, and \lim all behave the same way,
you just need to understand when the subscripts appear
beneath, and when on the side. Generally:
* running text $\sum_x$ => always side
* single-line equation mode $$\sum_x$$ or
\begin{equation}\sum_x\end{equation} => below, except:
* in fractions \frac{\sum_x}{\sum_y} => side
* in super- or subscripts: y^{\sum_x} => side
* in roots \sqrt{\sum_x} => side
* in matrices => side
Basically if \sum and others appear in restricted ve |
|
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f*****s
发帖数: 4 | 10 why the same fortran program gives quite different computational results?
the computation includes large matrices.
any common reason for this?
thanks a lot! |
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f*****s
发帖数: 4 | 11 yes, i used different compile flags. actually they give very close resutls
for relatively small matrices, but quite different for large ones.
can you tell me what kind of codes will cause such problem? thanks. |
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F****r
发帖数: 34 | 12 yes, the matrix is not square
just want to get the least aquare solution.
We already can got the result.
The problem is just time.
now we use the coarse grid, for one iteration it take about 1 day.
usually after 4 or 5 iteration we can see something in the result.
this is just the test version.
we need to try finer grids, it means larger matric inverse.
it may take a few days for iteration fineshed.
that is why we need to find the parallel library.
then we can use multiple processors to do this |
|
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c*********t
发帖数: 340 | 14 I used SAS for about 1 year and R for about 1 year. When I was using SAS I
was just dealing with small datasets. For the past year I've been working
with high-through put microarray data and R is extremely good at handling
data matrice. You can find a whole bunch of R tutorials online:-) |
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c*2
发帖数: 24 | 15 I think both ANOVA and t-tests would work. Which one is better depends on
the assumption. In ANOVA, you can do the three comparisons by setting up
contrast matrices. |
|
e*******o
发帖数: 4654 | 16 昨夜无眠，为了一个学生。
五年前，他在清华大学数学系四年级。他可以保送直接攻读博士学位，参加了我们
所的入学考试后，研究室建议我考虑他。面谈后，我同意了。
事情开始得非常顺利，他请我担任他大学毕业论文的导师，我给了他一个解矩阵半
张量积方程的小题目。讨论了几次之后，他就做下去了。他很快进入角色，做了一些小
的结果。他的毕业论文，我修改过。后来他告诉我，得了“优”。我也比较满意，觉得
他赢在了起跑线上。
硕博连读的第一年，他在研究生院上课，接触不多。第二年回所，我很快发现了他
的优点。从素质上说，他数学基本功扎实，和他讨论数学问题是一种享受。一些需要细
想或计算的问题，交给他就好了。少则数小时，多则一、两天，一定会给你一个“Yes
”或“No”的解答。
他在科研上的敏感性也很难得。例如在讨论布尔网络可控性时，他首先发现了控制
传递矩阵的特性，我们一起，很快导致了一个很简洁的能控性公式。这个公式不久后被
两个以色列人重新发现。碰巧我是他们文章的审稿人，我告诉他们：一模一样的公式我
们已经发表了。这是一个比较深刻的结果，后续引用也很多。没有他，这就不是... 阅读全帖 |
|
t*********o
发帖数: 78 | 17 昨夜无眠，为了一个学生。
五年前，他在清华大学数学系四年级。他可以保送直接攻读博士学位，参加了我们
所的入学考试后，研究室建议我考虑他。面谈后，我同意了。
事情开始得非常顺利，他请我担任他大学毕业论文的导师，我给了他一个解矩阵半
张量积方程的小题目。讨论了几次之后，他就做下去了。他很快进入角色，做了一些小
的结果。他的毕业论文，我修改过。后来他告诉我，得了“优”。我也比较满意，觉得
他赢在了起跑线上。
硕博连读的第一年，他在研究生院上课，接触不多。第二年回所，我很快发现了他
的优点。从素质上说，他数学基本功扎实，和他讨论数学问题是一种享受。一些需要细
想或计算的问题，交给他就好了。少则数小时，多则一、两天，一定会给你一个“Yes
”或“No”的解答。
他在科研上的敏感性也很难得。例如在讨论布尔网络可控性时，他首先发现了控制
传递矩阵的特性，我们一起，很快导致了一个很简洁的能控性公式。这个公式不久后被
两个以色列人重新发现。碰巧我是他们文章的审稿人，我告诉他们：一模一样的公式我
们已经发表了。这是一个比较深刻的结果，后续引用也很多。没有他，这就不是我们的
... 阅读全帖 |
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y*****s
发帖数: 1047 | 18 Not considering matrix effect, current LC-MS are reproducible and linear,
owing to robustness and precision of current instrumentation
If you inject the same sample multiple times, CV should be <20% if SNR is >5
And you should easily get a straight line through standard addition
However, mass spec is not a spectroscopic detection method by nature
sample matrix greatly impacts the signals,
1 pmol/L of peptide X in 10% acetonitrile shows a signal of 100, but the
same level of peptide in a plasma d... 阅读全帖 |
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m*******s
发帖数: 3142 | 19 http://gradworks.umi.com/33/45/3345729.html
Toward the solution of the eigenproblem: Nonsymmetric tridiagonal matrices
by Slemons, Jason, Ph.D., UNIVERSITY OF WASHINGTON
请能下载的同学传到sendspace.com上，给出link, 谢谢！ |
|
|
p******n
发帖数: 55 | 21 http://www.grc.org/amc.aspx
熟悉的名字不少啊
2016 Lecturers
◾Nieng Yan, Membrane Transport Proteins
◾Xiaowei Zhuang, Synaptic Transmission
◾Christopher J. Chang, Metals in Medicine
◾Mikhail Lukin, Quantum Science
2015 Lecturers
◾Karl Deisseroth, Amygdala in Health & Disease
◾David M. Sabatini, Lysosomal Diseases
◾Laura Kiessling, Carbohydrates
◾Gerbrand Ceder, Physical Metallurgy
◾Liang Fu, Superconductivity
2014 Lecturers
◾Kristi S. Anseth, Si... 阅读全帖 |
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d********m
发帖数: 3662 | 22 what's about the first one? I work extensively with covariance matrices but
I didn't actually note the so called special properties of eigenvectors of
symmetric matrix. |
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r**********e
发帖数: 587 | 23 Eigenvectors of symmetric matrix are orthoganoal to each other.
covariance matrices 就是 symmetric；eigenvector也就是PCA的principal
component啦
btw好奇我觉得你们数学都很强的样子，是还在做bioinformatics还是直接CS了？
but |
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d********m
发帖数: 3662 | 24 Random matrices在这么下面？hic的精华啊。
我对Erez刮目相看了。面试的时候我说这东西我现在不懂，在你那里开始之前我尽量学
会，现在我觉得他的谜之微笑应该是藐视之微笑了。真是无知者无畏啊。这么难，幸好
没去，不然估计几年后该学不会还是学不会。 |
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r**********t
发帖数: 247 | 25 My friend is looking for a Postdoc. He is a very nice guy. this is a good
opportunity.
The Illinois Sustainable Technology Center at University of Illinois Urbana-
Champaign is seeking one full time postdoctoral research associate to
conduct laboratory research, model simulation, and field studies concerning
the enviromental fate and transport of steroid hormones and verterinary
antibiotics derived from animal farms.
Responsibilities: The post-doctoral researcher will work with a team of
scienti... 阅读全帖 |
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q*****e
发帖数: 433 | 26 不了解学术只了解八卦~~还是让matrice同学来介绍一下把
算跟 |
|
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t********e
发帖数: 107 | 28 1. Mass Spectrometry-Based Metabolomics of Yeast, 2010, Joshua Rabinowitz
2. Hydrophilic interaction chromatography coupled to MS for metabonomic/
metabolomic studies, 2010, Ian D. Wilson,Journal of Separation Science
3. Hydrophilic stationary phases: A practical approach for the co-analysis
of compounds with varying polarity in biological matrices,2010,
E. Goucher,Journal of Separation Science.
4. Dual hydrophilic interaction-RP retention mechanism on polar columns:
Structural correlations and |
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w*q
发帖数: 1294 | 29 Hydrophilic stationary phases A: practical approach for the co-analysis of
compounds with varying polarity in biological matrices
http://www.sendspace.com/file/m1q971 |
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r**********t
发帖数: 247 | 30 【 以下文字转载自 ChemEng 讨论区 】
发信人: refinedheart (Lostemple), 信区: ChemEng
标 题: Postdoc opportunity at UIUC
发信站: BBS 未名空间站 (Wed Sep 21 18:49:26 2011, 美东)
My friend is looking for a Postdoc. He is a very nice guy. this is a good
opportunity.
The Illinois Sustainable Technology Center at University of Illinois Urbana-
Champaign is seeking one full time postdoctoral research associate to
conduct laboratory research, model simulation, and field studies concerning
the enviromental fate and transport of ster... 阅读全帖 |
|
|
|
g******h
发帖数: 101 | 33 http://chemistryjobs.acs.org/jobs#/detail/5305585/1,false
esearch Associate / Assay Development POSTED: Apr 04
Salary: $ 35,000.00 - 45,000.00 Location: East Lansing , Michigan
Employer: Michigan State University Type: Full Time - Experienced
Field of Specialization: Analytical Work Function: Quality Control/
Analysis, Research-Applied
Required Education: Doctorate
We seek an analytical/organic/medicinal chemist to develop assays to measure
pheromones and o... 阅读全帖 |
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m*******s
发帖数: 3142 | 34 【 以下文字转载自 Biology 讨论区 】
发信人: manifolds (流形), 信区: Biology
标 题: paper help
发信站: BBS 未名空间站 (Mon May 19 23:47:35 2014, 美东)
http://gradworks.umi.com/33/45/3345729.html
Toward the solution of the eigenproblem: Nonsymmetric tridiagonal matrices
by Slemons, Jason, Ph.D., UNIVERSITY OF WASHINGTON
请能下载的同学传到sendspace.com上，给出link, 谢谢！ |
|
m*******s
发帖数: 3142 | 35 【 以下文字转载自 Mathematics 讨论区 】
发信人: manifolds (流形), 信区: Mathematics
标 题: thesis help
发信站: BBS 未名空间站 (Mon Oct 27 01:26:54 2014, 美东)
http://gradworks.umi.com/34/76/3476639.html
Quasiseparable Matrices and Polynomials
Pavel G Zhlobich,
University of Connecticut
请能下载的同学传到 sendspace.com, 谢谢！ |
|
g***i
发帖数: 90 | 36 未必阿。部分行是可以的如
[2 1 0
1 2 1
0 1 2]
关于positive definite, diagnonal dominant matrices, 确切
的常用结论大概只有strictly diag dom ==> psd |
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w*******n
发帖数: 7 | 37 x1,y1,x2,y2 are in R3,
x1 and y1 are linearly independent,
x2 and y2 are linearly independent,
Consider two planes P1=(x1, y1), P2=(x2,y2).
Suppose we need to find a nonzero vector v in R3 that lies in the intersection
of P1 and P2. Devise a method for solving this problem by reducing it to the
computation of QR factorization of three 3by2 matrices. |
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r****y
发帖数: 1437 | 38
Are A and B square matrices? If not, may not have unique solutions. |
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r****y
发帖数: 1437 | 39 If now you have (x, y, z)
(x, y, t)
matrices z and t are different a lot, so cannot use one colormap to cover
both of them.
Then how you can make a contour plot with one filled contours and one
contour-lines only?
If you just use
contourf(x, y, z);
hold all;
contour(x, y, t);
the second contour command will overwrite.
any good ideas? |
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r****y
发帖数: 1437 | 40 If your two matrices are same size, simple, just
x = M - N;
If they are not, you can still
x = M(ind) - N(ind)
where ind is a one-dimension array. Then x will end up as a vector.
No matter how many dimension a matrix is, it always saves as 1D vector in
memory. So you can always manipulate it as 1D vector.
. |
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n*s
发帖数: 752 | 41 r u talking about irreducible representation?
.
or |
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x******r
发帖数: 367 | 42 I am not sure about how irreducible representation is related to my topic.
Is it convenient for you to give me more hints?
BTW, I have never learnt lie group before.
Thanks. |
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n*s
发帖数: 752 | 43 first of all, it's not sth. can be explain all in a sudden
an example is about multiple electron spins, or taking the obital and spin
angular momentum together for 1 electron
in that case, a rotation can be written into tensor product form
D(total) = D(obital) \otimes D(spin)
or
D(2 electron) = D(1st) \otimes D(2nd)
in general, all matrix entries of D are not 0, which is not good for realistic
calculation. it is then found if we go to the irriducible representation, D
can be written into block-d |
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x******r
发帖数: 367 | 44 Ok.
Thank you very much.
realistic |
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x******r
发帖数: 367 | 45 Hello!
Thanks for your response.
Is it convenient for you to recommend some good papers or books on this topic
so that I can try your suggested methods?
realistic |
|
n*s
发帖数: 752 | 46 i am not sure what u want to know
as for how to decomposite a rotation matrix into block diagnalized form, u can
find it in any advanced quantum mechanics books, such as Sakurai's Modern
Quantum Mechanics
topic |
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x******r
发帖数: 367 | 47 Thank you very much.
can |
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r****y
发帖数: 1437 | 48 For both eigen value and SVD, you can iterativelly solve it, get the
first n largest eigen values/singular values and corresponding vectors.
If you use matlab, matlab has available routine for sparse matrices,
you can easily calculate the first-n components you want.
1000000*
最 |
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l*****i
发帖数: 3929 | 49 lsqcurvefit - Solve nonlinear curve-fitting (data-fitting) problems in least
-squares sense
Equation
Find coefficients x that best fit the equation
given input data xdata, and the observed output ydata, where xdata and ydata
are matrices or vectors of length m, and F (x, xdata) is a matrix-valued or
vector-valued function.
The lsqcurvefit function uses the same algorithm as lsqnonlin, and provides
an interface designed specifically for data-fitting problems.
Syntax
x = lsqcurvefit(fun,x0,xdata,y |
|
x*z
发帖数: 381 | 50 我正在用matlab的lmisolver解线性矩阵不等式，碰到一个问题如下：
我需要求解A(X1,X2)<0, where X1 and X2 are unknown matrices,
所以我用lmisolver已经得到一个数值解X1_0和X2_0，为了验证结果，
我计算矩阵A(X1_0,X2_0)的eigenvalues,发现一些在-3E-6附近，
现在我老板的担心是，这些特征值这么小，可能是由于Matlab的计算误差使得
所有特征值都满足小于0的要求。所以希望我得到一些别的数值解使得A矩阵的
特征值离y轴更远点。
我想请教大家，我老板的担心是多余的吗？难道Matlab连1E-6这种计算精度都达不到？
谢谢。 |
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