How do you integrate perpendicular to a plane if you don't have a concept of 3d? In that direction the plane is just a point.
Vectors in R do not have any concept of "n by 1"... they are like a string of beads. When you take a column out of a matrix `a` using indexing b <- a[,j] the resulting vector can only be indexed along its length as b[i]. Such a vector is indistinguishable in structure from a[i,] which originated from a row. So I would say you are tilting at windmills. If you want you can write a[, j, drop=FALSE] to end up with an n by 1 matrix... but that is not a vector, it is a matrix. I have reservations about the value of "integrating out" along a row in an n by 1 matrix... seems like a degenerate case and you would be better off not creating the n by 1 matrix in the first place. But then I left Matlab behind a long time ago. On June 11, 2024 11:44:08 AM PDT, "Levine, Michael" <mlev...@purdue.edu> wrote: >Hello all, > >I have a question concerning integration of a function of a multivariate >argument with respect to one or more variables in r. Let us say we have a >function > >F <- function(x){ body of the function} > >Where x is, in general, a d by 1 vector with d>1. Now I want to integrate out >some of the coordinates of x, e.g. x[1] or x[2] or both of them etc. I'm well >aware of how to integrate out e.g. y if a function is defined as f <- function >(x,y) {body of the function} where y is a scalar. >However, it seems to be quite difficult to do the same if the function is >defined with a vector argument x. At the very least, I haven't seen any good >examples of this being done. >Any suggestions? > >Yours sincerely, >Michael > >Michael Levine >Associate Professor, Statistics > >Department of Statistics >Purdue University >250 North University Street >West Lafayette, IN 47907 USA > >email: mlev...@purdue.edu >Phone: +1-765-496-7571 >Fax: +1-765-494-0558 >URL: www.stat.purdue.edu/~mlevins > > [[alternative HTML version deleted]] > >______________________________________________ >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. -- Sent from my phone. Please excuse my brevity. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.