interpolation

问题 in numerical analysis we students are obligated to implement code in R that given a function f(x) finds its Fourier interpolation tN(x) and computes the interpolation error $||f(x)-t_{N}(x)||=\int_{0}^{2\pi}$ $|f(x)-t_{N}(x)|^2$ or a variety of different $N$ I first tried to compute the d-coefficients according to this formular: $d = \frac 1N M y$ with M denoting the DFT matrix and y denoting a series of equidistant function values with $y_j = f(x_j)$ and $x_j = e^{\frac{2*pi*i}N*j}$ for $j =

问题 So I have some irregularly spaced data that I want to interpolate onto a regular grid. (I want to do exactly this but in Java) Here's a picture: Basically I have the x and y coordinates of each point and a z value associated with each point and I want to interpolate between them and fill in the center of my image. What is the best way to do this using Java? Is there a built in 2D interpolation library I can use or should I try a "roll my own" approach? This post and this one also seem to be

问题 I have a tcsh script that generates a text file. One of the lines in the text file is: bla bla bla 'foo foo foo "bar bar bar"': etc etc; Note the nested ' and " and also the : and ; that must be there. The : and ; require the whole string to be surrounded by quotation marks. However, if I do that, I have trouble escaping the quotation marks. The command is: echo "bla bla bla 'foo foo foo "bar bar bar"': etc etc;" >> outfile How can I escape the quotation marks around bar bar bar so that they

问题 I would like to do some piecewise cubic hermite interpolation and get the roots of the polynomials. (I used to do this in matlab but would now like to implement this in python 3.4). I tried to use the scipy PchipInterpolator. Interpolation is OK but when I tried to retrieve the roots I got this error... I now am stuck here and could'nt find any workaround. Here is a simple code reproducing what I do and the exact error message... import matplotlib.pyplot as plt from scipy import interpolate,

问题 Given a set of points in (X, Y, Z) coordinates that are points on a surface, I would like to be able to interpolate Z-values at arbitrary (X, Y) coordinates. I've found some success using mlab.griddata for interpolating values on a grid, but I want to be able to call a general use function for any (X, Y) coordinate. The set of points form a roughly hemispherical surface. To simplify the problem, I am trying to write a method that interpolates values between known points of the hemisphere

问题 A recent immigrant to Python and scientific computing with Python. This is a question to avoid any duplication of code that might already exist. I have a field that is sampled as a function of x and y in a regular grid. I would want to interpolate the data to obtain not only the value of the field at any point on the grid, but also the first and second derivatives. If I interpolate it with bicubic interpolation using interp2d, I can obtain the value of the field. Does anyone have a suggestion

问题 Angular 2 rc3 I am trying to dynamically add calc() to an element in a template. I have something like this. template : `<div attr.style.width="{{width}}></div>"` export myClass { @Input() myInputObject:any; private width:string; ngOnInit() { this.setWidth()} private setWidth() { let percent = myInputObject.percent; this.width = 'calc(' + percent + '% - 20px)'; } } If I use the parenthesis the ouput looks like this in the DOM. <div style="unsafe"></div> If I take out the parenthesis it works

问题 I have an array[160,160] with 27 measured datapoints and want to interpolate the whole array. I have found the following code, but don't get it which parameters I have to hand over so that this method works: public static double BilinearInterpolation(double[] x, double[] y, double[,] z, double xval, double yval) { //calculates single point bilinear interpolation double zval = 0.0; for (int i = 0; i < x.Length - 1; i++) { for (int j = 0; j < y.Length - 1; j++) { if(xval>=x[i] && xval<x[i+1] &&

问题 Right now, I have more than 25 vertices that form a model. I want to interpolate color linearly between the first and last vertex. The Problem is when I write the following code glColor3f(1.0,0.0,0.0); vertex3f(1.0,1.0,1.0); vertex3f(0.9,1.0,1.0); . .`<more vertices>; glColor3f(0.0,0.0,1.0); vertex3f(0.0,0.0,0.0); All the vertices except that last one are red. Now I am wondering if there is a way to interpolate color across these vertices without me having to manually interpolate color

问题 Making a Blackberry app, want a Gradient class. What's the most effective way (as in, speed and battery life) to interpolate two colors? Please be specific. // Java, of course int c1 = 0xFFAA0055 // color 1, ARGB int c2 = 0xFF00CCFF // color 2, ARGB float st = 0 // the current step in the interpolation, between 0 and 1 Help from here on. Should I separate each channel of each color, convert them to decimal and interpolate? Is there a simpler way? interpolatedChannel = red1+((red2-red1)*st)