similar to: How to draw the graph of f(x,y) = x * y ?

Displaying 20 results from an estimated 3000 matches similar to: "How to draw the graph of f(x,y) = x * y ?"

2010 Mar 13
2
dmvnorm masked by emdbook
I am using curve3d in the emdbook package to graph a gaussian copula density function generated via the copula package. Unfortunately, it appears that emdbook masks dmvnorm from the package mvtnorm in a way that prohibits copula from generating the gaussian copula. (Sounds very confusing!) For example, > library(copula) > f<-function(x,y) dcopula(normalCopula(0),c(x,y)) >
2011 Apr 12
1
2-parameter MLE problems
Hi all, Sorry for the re-post, I sent my previous e-mail before it was complete. I am trying to model seroprevalence using the differential equation: dP/dt = beta*seronegative*.001*(seropositive)-0.35*(0.999)*(seropositive)-r*seropositive. I would like to estimate my two parameters, beta and r, using maximum likelihood methods. I have included my code below:
2011 Mar 07
1
More appropriate optimization routine?
Hello! I have 2 variables - predictor "pred" and response variable "DV": pred<-c(439635.053, 222925.718, 668434.755, 194242.330, 5786.321, 115537.344, 100835.368, 7133.206, 159058.286, 4079991.629, 3380078.060, 2661279.136, 2698324.478, 1245213.965, 1901815.503, 1517019.451, 1396857.736, 1034030.988, 432249.574, 342329.325, 1831335.792, 2209578.859, 1641709.754,
2010 Apr 14
2
curve
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2008 Sep 26
1
Generating a valid covariance matrix
I want to generate a valid variance-covariance matrix. One way could be to generate some random sample from multivariate normal distribution and then calculate cov. matrix. Another way could be to sample from wishart distribution itself. However both cases need a valid i.e. PD covariance matrix. As I need to generate that covariance matrix only, I am not interested those two methods. Can anyone
2008 Oct 26
3
weird behavior with the 3rd root....
Well, this is what i got... > -0.0841219200008394^(1/3) [1] -0.438163696867656 > (-0.0841219200008394)^(1/3) [1] NaN and i don't have a clue of why this happens or how to avoid it, any suggestions? thank you, Juan
2008 Sep 23
1
Generalising to n-dimensions
Hi R-helpers, I have two queries relating to generalising to n dimensions: What I want to do in the first one is generalise the following statement: expand<-expand.grid(1:x[1],1:x[2],...1:x[n]) where x is a vector of integers and expand.grid gives every combination of the set of numbers, so for example, expand.grid(1:2, 1:3) takes 1,2 and 1,2,3 and gives 1,1 2,1 1,2 2,2 1,3 2,3 My x
2012 Mar 12
1
How to add/draw a persp3d graph to a plot with an existing surface/graph
Dear R users, I have been trying to draw the following 3d graphs: The solid region bounded above by the paraboloid z = 9 - x2 - y2 and below by the unit circle in the xy-plane. I wanted to visualize the solid region bounded by those two graphs. I could draw those two 3d graphs separately, but I could not get those two to work in one single plot. Here's my code for the paraboloid: x <-
2004 Dec 08
2
similarity matrix conversion to dissimilarity
I have a matrix of similarity scores that I want to convert into a matrix of dissimilarity scores so that I can apply some clustering methods to the data. That is, high values in my matrix signify similarity and low values (zero being the lowest) signify no similarity. What functions/options in R or its packages are available for making this kind of transformation of a matrix?
2012 Aug 27
1
RGL plot : lighting problem when triangle3d and persp3d are used in the same plot
Dear all, I have tried to plot a triangular matrix with the function persp3d(rgl). for example z=rbind(c(1,NA,NA,NA),c(5,3,NA,NA),c(4,2,9,NA),c(8,6,5,11)) x=1:4 y=1:4 persp3d(x,y,z,color="gray") The two extreme points are not plotted (value=1 and value=10). It seems because the half of the matrix have 'NA' and perp3d need planar quadrilateral face. So I decided to use the
2010 Jul 30
3
simple table/matrix problem
Hi Given three vectors x <- c(fish=3, dogs=5, bats=2) y <- c(dogs=1, hogs=3) z <- c(bats=3, dogs=5) How do I create a multi-way table like the following? > out x y z bats 2 0 3 dogs 5 1 5 fish 3 0 0 hogs 0 3 0 ('out' is a matrix). See how the first line shows 'x' has 2 bats, 'y' has zero bats, and 'z' has 3 bats and so on for each
2009 Jun 12
1
bundle deprecation
Hi I read that bundles are to be deprecated in 2.10. The BACCO bundle contains three packages (emulator, calibrator, approximator) which I am happy to unbundle. But the 'BACCO' moniker has some considerable cachet for me in terms of recognizability (eg with grant-giving bodies), as it has become an umbrella term for a whole bunch of related statistical functionality of which the three
2010 Nov 10
1
S4 package warning
Hello everyone. R-2.12.0, suse linux 11.3. I am debugging a package that uses S4 methods and R CMD check gives the following warning: > Warning in methods::findMethods(g, env) : > non-generic function 'mdm' given to findMethods() > See the information on DESCRIPTION files in the chapter 'Creating R > packages' of the 'Writing R Extensions' manual. I
2008 Sep 19
6
how to keep up with R?
Dear Listers, I've been a big fan of R since graduate school. After working in the industry for years, I haven't had many opportunities to use R and am mainly using SAS. However, I am still forcing myself really hard to stay close to R by reading R-help and books and writing R code by myself for fun. But by and by, I start realizing I have hard time to keep up with R and am afraid that I
2010 Jun 29
3
table() of a factor
Hi suppose I have a factor 'x': > x <- as.factor(c(rep("a",3),"b","d")) > table(x) x a b d 3 1 1 > > But this is not what I want because I need to include the fact that the count of "c" is zero. I can't just change the levels of x: > levels(x) <- c("a","b","c","d") >
2009 Oct 16
1
generalization of tabulate()
Hi I want a generalization of tabulate() which works on rows of a matrix. Suppose I have an integer matrix 'observation': > observation y1 y2 y3 1 4 0 1 4 0 2 0 3 4 1 0 0 5 0 0 1 4 2 0 3 Each row corresponds to a (multivariate) observation. Note that the first two rows are identical: this means that data "c(1,4,0)" was observed twice. Now suppose I can list the sample
2007 Mar 16
2
Can I scale the labels in a 'persp' graph?
Hi all: I'm using 'persp' for 3D graphics. I need the axis's labels smaller than by defect. I see in 'help()', the information about 'par()'. I have wrote: >par(.....,cex.axis=0.5,cex.lab=0.5) perspc(.................) and the result don't change. The question is: Can I change the size of labels in the perps graph?? Thank you in advance: /salva
2007 Mar 16
2
Can I scale the labels in a 'persp' graph?
Hi all: I'm using 'persp' for 3D graphics. I need the axis's labels smaller than by defect. I see in 'help()', the information about 'par()'. I have wrote: >par(.....,cex.axis=0.5,cex.lab=0.5) perspc(.................) and the result don't change. The question is: Can I change the size of labels in the perps graph?? Thank you in advance: /salva
2012 Nov 19
2
Ben Bolker's '‘emdbook’ Package , rbetabinom
Hello, I am using rbetabinom ( to generate beta binomial random variables) function available in the "emdbook"package written by Professor. Ben Bolker for my research study. I have no questions with this function. However, I am looking for the theoretical method/algorithm of the function "rbetabinom " . Morris (1997), American Naturalist 150:299-327 is given as the reference
2013 Jun 25
1
Correct scaling of axis in persp3d plot
Hi, I want to format my axis in my persp3d plot. With my data, which I attached I created a persp3d plot with the following code, which I summarized from different code snippets I found: library(rugarch)library(rgl)library(fGarch)fd <-as.data.frame(modelfit,which ='density')color <-rgb(85,141,85,maxColorValue=255)x <-seq(-0.2,0.2,length=100)y <-c(1:2318)f