search for: stepfunction

Dear members, I would like a help for extracting the values from a step function (stepfun). >From help(stepfun) we have the following example: Y0<-c(1.,2.,4.,3.) y0<-c(1.,2.,3.,4.) sfun<-stepfun(1:3,y0,f=0) plot(sfun) Now, suppose instead I was given the object (*sfun*, say) from which I wanted to extract the values generated by the function *stepfun*. More precisely, I want to

Before re-inventing the wheel I would like to ask: does anyone know about an optimizer in R which can reliably identify which value of X (Xopt) leads to Y (Yopt) closest to Ytarget in Y <- MonotoneStepFun(X) optionally with the restriction that Yopt <= Ytarget (at least if any Y <= Ytarget, otherwise any Yopt > Ytarget would be the preferred answer) If none is known, I will write

I have made the 3-d case do the same as the vector case, which is what the C code clearly intended (a goto label was in the wrong place). This leaves the bigger question of the right thing to do. I note that data frames give an error when any indices are NA. -thomas On Fri, 3 Sep 2004 ripley@stats.ox.ac.uk wrote: > Apart from the inconsistencies, there are two clear bugs here: > > 1)

If anyone has a very fast vectorized method for doing the following I would appreciate some help. I want to avoid outer() to limit memory problems for very large n. Let x = real vector of length n y = real vector of length n w = real vector of length m, m typically less than n/2 but can be > n z = real vector of length m For w[i], i=1,,,m, find the value of x that is closest to w[i]. In