spline

问题 is there a way to calculate the curvature in a specific point having a smooth.spline curve (or similar)in R? The curve is calculate from a set of x,y points. Thank you in advance. 回答1: This one is actually very easy if you know that there is a predict() method for objects created by smooth.spline() and that this method has an argument deriv which allows you to predict a given derivative (in your case the second derivative is required) instead of points on the spline. cars.spl <- with(cars,

问题 I feel like this is an easy question... How do you identify coordinates in a figure? I plotted some data, used unireg (the uniReg package) to make a spline curve, and want to pull out the data from a point. library(uniReg) P0mM <- read.table(text=" Time FeuM 0.04 138.8181818 7 1258.636364 14 1320.545455 21 2110.37037 28 13730.37037 35 1550.909091",header=TRUE) z=seq(min(P0mM$Time),max(P0mM$Time),length=201) uf=with(P0mM,unireg(Time,FeuM,g=5,sigma=1)) plot(FeuM~Time,P0mM,ylim=c(0,16000),ylab=

问题 I have a serial data formatted as follows: time milk Animal_ID 30 25.6 1 31 27.2 1 32 24.4 1 33 17.4 1 34 33.6 1 35 25.4 1 33 29.4 2 34 25.4 2 35 24.7 2 36 27.4 2 37 22.4 2 80 24.6 3 81 24.5 3 82 23.5 3 83 25.5 3 84 24.4 3 85 23.4 3 . . . Generally, 300 animals have records of milk in different time points of short period. However, if we join their data together and do not care about different animal_ID, we would have a curve between milk~time like this, the line in figure below: Also, in the

问题 I am trying to add text (the nonlinearity p-value) to a plot of a restricted cubic spline regression model. When I try this in R studio it works fine, however the moment I try to add code to save it as a .tiff file, I get the following: Error in strwidth(legend, units = "user", cex = cex, font = text.font) : plot.new has not been called yet This is my code (for a restricted cubic spline regression model for the association between determinant labtsh and endpoint ecard with 3 knots): spline <-

问题 I am having problems with the derivativeAt() method when using the BSpline path because it is not returning the correct values, however the derivativeAt() method works find for the CatmullRomSpline path so this is something specific to SPline. The wiki and API do not mention that the SPline needs to be treated differently from other paths...is there something that I’m missing with SPline, or is this a bug with LibGDX? I made a simple program to show the problem. It draws the control points

问题 I'm using LibGDX for my Android app. I need to move and orient 3D object(ModelInstance) along a spline.In my case it's CatmullRomSpline. I got the movement working but having problem with orienting the ModelInstance along the spline. My Code: public void update() { float t = SPEED * Gdx.graphics.getDeltaTime(); elapsedTime = elapsedTime + SPEED * Gdx.graphics.getDeltaTime(); //Movement catmull.valueAt(value, elapsedTime); myObject3d.transform.setTranslation(value); //Rotation derivative =

问题 I have some discrete coordinates with their heights and I need to create a smooth surface which I will continue to use. I need to have heights for all the coordinates in that surface. I was considering using a 3D spline but I am having trouble applying the methods suggested in comparable kind of questions. I am not an experienced programmer so I would probably find any suggestions helpful. Please forgive me if I may asked something very similar to what was already discussed before. I am using

问题 I have a measurment of which should fit an hysteresis. For visualisation purpose I would like to plot a line approximating the hysteresis to help explain this pattern. I created an example in the following image using the code below. I would like to have an output similar to the green curve - however I don't have this data directly available, and I don't care whether it is pointy. However most smoothing functions such as smooth.spline which I plotted in blue - allow no loops. The closest I

问题 I have some data points which I like to approximate with a cubic b-spline fit. In an other program, I like to interpolate some points using only the fitted knots and coefficients. This means that I need to write the code to evaluate a point given the knots and coefficients myself. Using this wiki page, I was already able to evaluate various points correctly with the result of knots,coeff,n=scipy.interpolate.splrep(x,y) Strangely, I needed to remove the first and last 3 entries in the arrays

问题 I am creating an areaspline highcharts. As I am not setting any color it should default to the default blue. For me its automatically filling with rgba(247, 163, 92, 0.75); . Why is that happening. How can I get the default darker blue on the top border and the default blue inside the areaspline. Here is my code: let series_vals = []; let data_array = []; let val_array = []; for (let i = 0; i <= 15 i++) { series_trend.push("series_trend" + i); data_array.push([]); val_array.push(val); } let