search for: derivi

Dear R Helpers: I am trying to annotate a plot. The following code snippet works, but it is kind of a kludge since it adds the partial derivative symbols after creating the plotmath frac(). Is there a more elegant way to write a partial derivative? dev.off() plot(NA, xlim=c(-3,3), ylim=c(0,1.6), xlab="", ylab="", tck=-0.015) text(1.6, 1, expression(paste("slope =

What functions exist for differentiating a numeric vector (in my case spectral data)? That is, experimental data without an analytical function. ie, > x <- seq(1,10,0.1) > y=x^3+rnorm(length(x),sd=0.01) #although the real function would be nothing simple like x^3... > derivy <- .... I know I could just use diff(y) but it would be nice to estimate derivatives at the

...is function with respect to specifying the constraints and so I don’t know if it is what I need. The command is: constrOptim(theta, f, grad,ui,ci,…). “theta” is the initial value of the variables in the function, “f” and “grad” are the function to be optimized and its gradient functions (partial deriviatives). Now, “ui” and “ci” are stated to be constraints in the help documentation but it is not explained how these constraints are to be specified. To be concrete, here is my objective function: f<- -1*pi*log(pi) i.e. the entropy of a vector of probabilities (pi) The constraints are...

A few days ago, I sent a question to the r-help list enquiring about the *** LEGALITY *** of porting a function from Splus into R. As a particular example, I referred to error.bar. Several people posted code for various versions of error.bar which they had written, but that was NOT WHAT I WAS ASKING FOR/ABOUT!!! [Can't anybody ***read*** these days?] I asked: IS IT

We have had some conversation within R core, lead by Duncan Murdoch and me, about a proposal to extend the current tracingState() functionality by something tentatively called debuggingState(). Duncan has allowed me to copy the previous conversation (after very minor editing): The following is quite technical and assumes you know more about R's debug()ing and trace()ing than an estimated

...be able to reference derivative-specific symbols from common code, but currently we'll halt execution at runtime when we have undefined symbols. This is a problem, for example, when we need to reference PXE functions from common code. The solution proposed here is to define any symbols that are deriviative-specific (and so may not even *exist* for some derivatives) to be weak, that way the ELF module code can resolve them to a default function that should never be invoked (and will print an error message and halt execution if it is). Matt Fleming (5): core/elflink: Delete ADV code that's...