similar to: approximate function and find local peaks (Maxima or Minima)

Hi there, I use the surf.gls() function to fit a variable measured over a surface. When I plot the predicted surface, there are local minima/maxima in almost every coordinate where data were measured, which seems aberrant. For instance: ?? x <- c(343,293,343,243,293,343,443,543,593,243,293,343,393,443,493,543,593,143,193,243,293,343,393,443,

I have data in the form of (x,y) pairs and would like to find local minima and maxima (typically the zeros of the 2nd derivative) of the y values. I looked at numericDeriv, but I don't have an "expression" per se. I looked at optim, also, but it looks like it will find only one "global" max or min. I can code up my own piecewise derivatives, but wondered if there is

Dear R users, How to find all single minima within each next part of analyzed vector (table) Select all minima (mass_value=min & mass_value<2) (many) in vector(table), BUT first put mask on table in order to select within one window mask (5 elements) only one local minimum, and next to search within the next time window mask the second minimum (only one local along second mask)

Hello, I am trying to use optim() on a function involving a summation. My function basically is a thinned poisson likelihood. I have two parameters and in most cases optim() does a fine job of getting the minima. I am simulating my data based on pre specified parameters, so I know what I should be getting. However when my true parameters fall in a particular range, optim() gives

I am using numerical optimization to fit a 1 parameter model, in which the input parameter is bounded. I am currently using optimize(), however, the problem turns out to have local minima, and optimize does not always seem to find the global minimum. I could to write a wrapping function that tries multiple intervals or starting values, but I would prefer a package that has built-in methods to make

Dear all, I wonder which R algorithm could perform a search of local maxima in an spatial grid, in other words, having the coordinates of a map (x,y,z... up to 6 coordinates) and then the altitude/height at each point (h) (in total 7 numerical variables) I would like to localise the peaks (local maxima) of that topological surface. Which R algorithm can perform this? Thanks a lot, Josep Maria,

Hi I have a large dataset which follows a multimodal distribution. And I would like to identify the maxima. As the data is obtained from a stochastic simulation, not all maxima in the data are "real maxima of the dirstribution" but rather small random fluctuations. Unfortunately, it is not possible for me to run more simulations to smooth the obtained distribution. What I am doing

I have a Gaussian mixture model with some parameters mean=(506.8644,672.8448,829.902) sigma=(61.02859,9.149168,74.84682) c=(0.1241933, 0.6329082, 0.2428986) And the plot look something like below.[image: enter image description here] <https://i.stack.imgur.com/4uUQ9.png> Also, if I change my parameters to mean=(2.15,2.0,2.9) sigma=(0.1,0.1,0.1) c=(1/3,1/3,1/3) Then plot would change

?dv?z?lj?k az Egyperces olvas?inak t?bor?ban!

Hello, I'm aware that recently there has been discussion of R joining forces with an algebra system in some way. Here is my $0.02. I suggest linking R with Maxima (http://maxima.sf.net). Maxima is written in Lisp. Maxima objects are pretty simple. Maxima works on expressions, and almost every expression is a Lisp list of the form ((op) arg1 arg2 arg3 ...) which associates an operator and

Dear all, suppose I have a bi-variate function f(x,y), I want to find the maxima. I define x and y vector, and get matrix z=f(x,y). how can I get which (x0,y0) makes z become the maxima? I can do two loops to get the x0 and y0, but I think there may exist a function to do this.

If a run a LOESS model and then produce a smoothed surface: Is there any way to determine the coordinates of the local maxima on the surface? [[alternative HTML version deleted]]

Dear R users, I have created a Loess surface in R, in which x is relative longitude by miles, y is relative latitude by miles, and z is population density at the neighborhood level. The purpose is to identify some population centers in the region. I'm wondering if there is a way to determine the coordinates (x,y) of each center, so I can know exactly where they are. Let me use the

Is there any R package that can help me with digging out the maxima of a 1-D trajectory ? I have 975 1-D curves. They are only known as time series. That is a set of points ordered with respect to time. Some curves exhibit one only peak. Others have two peaks of different height. We wish to find the number of peaks and their position along the time axis. Apparently it's a trivial problem

Please keep the list in cc. Sorry, it didn't work as expected. Maybe someone else have an appropriate solution. Best, Ulrik On Sa., 26. Aug. 2017, 12:57 niharika singhal <niharikasinghal1990 at gmail.com> wrote: > Hi > > Thanks for you mail, > I really appreciate your time on my problem > > I have posted this problem on > > >

> On 26 Aug 2017, at 16:39, niharika singhal <niharikasinghal1990 at gmail.com> wrote: > > Hi, > > Thanks for your mail, and time > > It is not working for some arguments, when mean value is like >6. > > > case > > mc0 <- c(0.08844446,0.1744455,0.1379778,0.1209769,0.1573065,0. > 1134463,0.2074027) > > rv

Hi. Suppose I have a vector that I partition into disjoint, contiguous subvectors. For example, let v = c(1,4,2,6,7,5), partition it into three subvectors, v1 = v[1:3], v2 = v[4], v3 = v[5:6]. I want to find the maximum element of each subvector. In this example, max(v1) is 4, max(v2) is 6, max(v3) is 7. If I knew that the successive subvector maxima would never decrease, as in the example,

I''m looking to write a javascript heavy clientside program with a something serverside backend that connects to the free maxima math program. I have extensive knowledge of ruby on rails, so I would prefer to call Maxima with ruby, but I don''t know if this is even possible. Its fairly easy to call Maxima (with a lisp implementation) using ANSI C, it is a little less easy to

Dear Niharika, As I said before, the problem is basically an optimization issue. You should isolate the problematic part from the rest of your study. Sometimes, more information does not help to solution. All the answers from us (Ulrik, David, me) are more or less are correct to find a maximum point. Newton?s method is also correct. But after answers, you only say, it didn?t find the right