Displaying 11 results from an estimated 11 matches for "gridpoints".
2013 Apr 13
0
help on smoothing volatility surface..
...piration's line then interpolate.... ??
library(RQuantLib)
library(quantmod)
library(rgl)
library(akima)
library(ggplot2)
library(plyr)
GetIV <- function(type, value,
underlying, strike,dividendYield, riskFreeRate, maturity,
volatility,
timeSteps=150, gridPoints=151) {
AmericanOptionImpliedVolatility(type, value,
underlying, strike,dividendYield,
riskFreeRate, maturity, volatility,
timeSteps=150,
gridPoints=151)$impliedVol
}
GetDelta <- function(type, underlying, strike,...
2006 Jun 14
1
Estimate region of highest probabilty density
...d and modified
# ===============================
library(MASS)
kde2d.weighted <- function (x, y, w, h, n = n, lims = c(range(x), range(y))) {
nx <- length(x)
if (length(y) != nx)
stop("data vectors must be the same length")
gx <- seq(lims[1], lims[2], length = n) # gridpoints x
gy <- seq(lims[3], lims[4], length = n) # gridpoints y
if (missing(h))
h <- c(bandwidth.nrd(x), bandwidth.nrd(y));
if (missing(w))
w <- numeric(nx)+1;
h <- h/4
ax <- outer(gx, x, "-")/h[1] # distance of each point to each grid point in x-direction
ay...
2006 Dec 13
2
caching frequently used values
...mpute and store some
frequently used matrices "on demand". The Matrix package already uses
something like this for storing decompositions, but I don't know how
to do it.
The actual context is the following:
A list has information about a basis of a B-spline space (nodes,
order) and gridpoints at which the basis functions would be evaluated
(not necessarily the nodes). Something like this:
bsplinegrid <- list(nodes=1:8,order=4,grid=seq(2,5,by=.2))
I need the design matrix (computed by splineDesign) for various
derivatives (not necessarily known in advance), to be calculated by
the...
2006 Nov 07
1
multivariate splines
Hi,
I am looking for an R package that would calculate multivarite (mostly
2d and 3d, tensor) cubic interpolating splines, so that I could
evaluate these splines (and their derivatives) at many points (unkown
at the time of calculating the spline polynomials) repeatedly.
To make things concrete, I have an array V with
dim(V) = k
and gridpoint vectors grid=list(...), length(grid[[i]])==k[i],
2011 Aug 15
2
area under the curve
...else {
if (is.function(y))
y <- y(x)
else if (length(y) != length(x))
stop("Mismatch in lengths of x and y.\n")
s <- order(x)
x <- x[s]
ddd <- diff(x)
if (any(ddd == 0))
stop("Gridpoints must be distinct.\n")
equisp <- isTRUE(all.equal(diff(ddd), rep(0, length(ddd) - 1))) y <- y[s]
}
n <- length(x) - 1
if (equisp) {
old.op <- options(warn = -1)
on.exit(options(old.op))
M <- matrix(y, nrow = n + 2, ncol =...
2003 Feb 27
4
What's in a name?
Hi,
Let's play a little game. Forget all you know, or think you know.
Without any context at all, what does the following pattern make you think
of?
<p> X -> X X -> X
| ^
v |
X <- X X <- X
| ^
v |
X X -> X X
| ^ | ^
v | v |
X -> X
2009 Jul 20
5
heatmap plot
Dear R community!
I am trying to create a heatmap based on the following data. As you can see the diagonal (0,0 to 10,10) is always 0). If I run the heatmap command like i posted it I get a graph with horizontal lines.
What is my mistake?
> heatmap(activity.matrix, Rowv = NA, Colv = NA, scale="column", xlab="x Compounds", ylab="y Compounds",
2008 Jul 01
2
Area Under a Curve
I would like to integrate the area under a curve without any smoothing or
the like- just on the raw numbers. I looked at integrate() but it requires
a function which I assume means something like x+x^2+x^3
is there a built in function in R for this?
#let's say
x <- seq(1:50)
y <- seq(1:50)
plot(y~x)
# the are would be 1250
# I would like to be able to do this but on more complicated
2006 Apr 23
2
distribution of the product of two correlated normal
Hi,
Does anyone know what the distribution for the product of two correlated
normal? Say I have X~N(a, \sigma1^2) and Y~N(b, \sigma2^2), and the
\rou(X,Y) is not equal to 0, I want to know the pdf or cdf of XY. Thanks
a lot in advance.
yu
[[alternative HTML version deleted]]
2011 Jan 17
2
Difficult with round() function
Dear list,
I'm writing a function to re-grid a data set from finer to coarser
resolutions in R as follows (I use this function with sapply/apply):
gridResize <- function(startVec = stop("What's your input vector"),
to = stop("Missing 'to': How long do you want the fnial vector to be?")){
from <- length(startVec)
shortVec<-numeric()
tics <- from*to
2006 Jan 28
3
Creating 3D Gaussian Plot
Hello,
I requested help a couple of weeks ago creating a dipole field in R but
receieved no responses. Eventually I opted to create a 3d sinusoidal plot
and concatenate this with its inverse as a means for a "next best"
situation. It seems that this isn't sufficient for my needs and I'm really
after creating a continuous 3d gaussian mesh with a "positive" and