Displaying 20 results from an estimated 20000 matches similar to: "Black-Litterman model"
2011 Sep 26
1
How to determine the efficient frontier portfolios using the Black-Litterman model?
I'm trying to find 50 portfolios on the efficient frontier using the
Black-Litterman model but have not found a suitable method for doing so. I
tried using the "portfoliosFrontier" function given in the package
fPortfolio using the "optimalPortfolios.fPort" function on package "BLCOP"
but does not provide satisfactory results
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2009 Jun 05
15
Rails Code Indentation
Hi All,
Rails code must be readable, formatted and well indented.
I wanted to do indent code in my previous projects.
Is there any built in rails plugin/gem that can help me to
indent my existing code.
Any ideas will be really appreciated !
NOTE: Please don''t suggest editor plugins.
Thanks & Regards,
Sandip R~
--
Ruby on Rails Developer
http://sandip.sosblog.com
2006 Mar 03
5
avoiding nil object error?
I''m a total Rails newbie and i''ve been struggling for hours today
with one (prolly very silly) problem:
I have a table portfolios that has many images:
class Portfolio < ActiveRecord::Base
has_many :images
end
class Image < ActiveRecord::Base
belongs_to :portfolios
end
In the controller i define a list of active portfolios:
@active_portfolios =
2011 Jul 07
2
elimination duplicate elements sampling!
Hi everyone!
I have a data frame with 1112 time series and I am going to randomly
sampling r samples for z times to compose different portfolio size(r
securities portfolio). As for r=2 and z=10000,that's:
z=10000
A=seq(1:1112)
x1=sample(A,z,replace =TRUE)
x2=sample(A,z,replace =TRUE)
M=cbind(x1,x2) # combination of 2 series
Because in a portfolio with x1[i]=x2[i],(i=1,2,...,10000) means a 1
2008 Nov 18
2
anyone familiar with this error?
[whit at linuxsvr R.packages]$ sudo R CMD INSTALL portfolio.construction
* Installing to library '/usr/local/lib64/R/library'
* Installing *source* package 'portfolio.construction' ...
** R
** preparing package for lazy loading
Loading required package: fts
Loading required package: quadprog
Loading required package: Rexcelpoi
terminate called after throwing an instance of
2012 Feb 15
2
Control number of assets in resulting portfolio with optimizations using package fPortfolio
Dear All,
I am using package fPortfolio to run minimum variance portfolio
optimizations in R. I already know how to set portfolioSpecs, portfolio
objects and constraints. Unfortunately I am not able to set the following
type of constraints.
I have a timeSeries object with returns data for roughly 1.5k assets for 261
subperiods (workingdays) and want to compute the global minimum variance
2011 Jan 07
1
Currency return calculations
Dear sir, I am extremely sorry for messing up the logic
asking for help w.r.t. my earlier mails
I have tried to explain below what I am looking for.
I have a database (say, currency_rates) storing datewise
currency exchange rates with some base currency XYZ.
currency_rates <- data.frame(date =
c("12/31/2010", "12/30/2010", "12/29/2010",
2011 Sep 15
1
portfolio, portfolio.optim function not found
Hello,
After installing and loading the package "portfolio", I tried to run the
example code provided, and it would not run.
this is the link:
http://rss.acs.unt.edu/Rdoc/library/tseries/html/portfolio.optim.html
this is the example code, as found at the link:
x <- rnorm(1000)
dim(x) <- c(500,2)
res <- portfolio.optim(x)
res$pw
the error I get is:
Error: could not find
2008 Sep 03
1
portfolio.optim and assets with weigth equals to zero...
Hello.
I don't understand a particular output of portfolio.optim (tseries).
I have 4 assets and the portfolio.optim returns an asset with weight equals
to zero.
If I do a portfolio.optim with 3 assets, without the asset with weight
equals to zero,
it returns a completely different result.
That's I would expected the same weights as the run with 4 assets.
Below the code.
Thanks in
2012 Oct 12
1
error msg using na.approx "x and index must have the same length"
Below I have written out some simplified data from my dataset. My goal is
to interpolate Price based on timestamp. Therefore the closer a Price is in
time to another price, the more like that price it will be. I want the
interpolations for each St and not across St (St is a factor with levels
A, B, and C). Unfortunately, I get error messages from code I wrote.
In the end only IDs 10 and 14 will
2012 Jul 23
1
Help with Portfolio Optmization
Hi,
I need some help with Portfolio Optimization problem. I am trying to find
the minimum variance portfolio subjected to constraints on weights like
/x1< w1 <x2
x3< w2 <x4</i>
I need help with solving for the minimum variance portfolio as solve.QP
doesn't allow me to specify the lower boundaries.
Thanks
Mahesh
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2006 Nov 10
1
Value at Risk historical simulation
Hi
Has someone got a package/script at hand to do a historical simulation
to calculate the Value at Risk?
If your not sure what Historical Simulation is:
In simple terms, Historical Simulation (HS) is just taking sample
percentiles over a moving sample. Suppose we want to use HS to predict
a portfolio's Value-at-Risk at a confidence level of 99 percent and
the window size is chosen to be 250
2008 Jul 21
1
portfolio optimization problem - use R
How to use R to solve the optimisaton problem
Minimize:
?*w^T*omega*w+mu^T*w+c^T(w-w0) for w>w0 long position
?*w^T*omega*w+mu^T*w-c^T(w-w0) for w<w0 short position
W: is the update weight of portfolio
Wo is the initial weight of portfolio
Omega is the variance covariance matrix
mu is the vector of return rate of stocks in the portfolio
C is the vector coefficient of transaction cost
2012 Jul 23
2
Bug in my code (finding nonzero min)
Can someone verify for me if the for loop below is really calculating the
nonzero min for each row of a matrix? I have a bug somewhere in the is
section of code. My first guess is how I am find the the nonzero min of each
row of my matrix. The overall idea is to make sure I am investing all of my
money, i.e. new.set is a set of indicator variables for each stock for a
particular portfolio, i.e.
2012 Jan 13
1
Portfolio Optimization
Hi,
I'm an R newbie and I've been struggling with a optimization problem for
the past couple of days now.
Here's the problem - I have a matrix of expected payouts from different
stock option strategies. Each column in my matrix represents a different
stock and each row represents the return to the strategy given a certain
market move. So the rows are not a time series of percentage
2004 Dec 10
1
Porting optimisation setup from Excel Solver to R
Hi all,
I am currently optimising a small portfolio I have
created as a part of my research project in Excel. I
am unable to find the appropriate package to port this
into R. My problem set up is as follows
Minimise ABS(Sum(Xi-Xi')+10*Sum(XiMi)/Mavg)
Subject to:
0 <= Xi <= 0.05
ABS(Sum(Xi)) = 0.2
where
Mi - Market Cap of Stock i
Xi - Initial weight of Stock i
Xi' - New weight of
2009 May 27
9
Contingent Select Boxes - 2 Q's
I have a form with contingent select boxes (the state is contingent on
the country selected, so when the country selected changes, the state
changes -- I am using the Carmen plugin for getting my state names and
country names together, but not the functionality I am interested in
achieving).
Everything works fine except I cannot figure out how to amend my code
such that:
A. When the form is first
2007 Nov 30
1
rollapply on zoo object
Dear R users.
I have zoo object "size_june" containing market-capital values:
> dim(size_june) # market-cap data of 625 firms for 20 years
[1] 20 625
> class(size_june)
[1] "zoo"
> size_june # colnames = "size.firmcode"
size.34020 size.4710 size.11050 size.10660 size.9540 size.8060
size.16160 size.8080 size.9280
1988-06-30 NA
2012 Jun 19
1
help with xy.coords(x,y)
i am working on the project to analyze hedge fund performance, i would
appreciate that if you guys could spare some time helping me out with the R
code. Thanks.
The senario is:
i applied BOXPLOT() to plot the performance of all hedge funds with 7
strategies.
And right now in this boxplot I need to plot the points of 30 individual
hedge funds from my portfolio. And I applied POINTS() and
2010 Apr 12
1
how to calculate a table
Hi R-Group,
I am stuck with the following problem: I am constructing a portfolio of
2 variables x and y
x <- rnorm(100, mean=100, sd=4)
y <- rnorm(100, mean=120, sd=10)
which I am combining as follows to a portfolio for sampling purposes:
portfolio <- c(rep(x, 8), rep(y, 2))
In this case I have assigned the weights of 8 and 2 to calculate the
bootstrapped mean:
mean.boot <-