interpolation

问题 I want to interpolate from x onto z . But there's a caveat: Depending on a state y , I have a different xGrid - which i need to interpolate. I have a grid for y , yGrid . Say yGrid=[0,1] . And xGrid is given by 1 10 2 20 3 30 The corresponding zGrid , is 100 1000 200 2000 300 3000 This means that for y=0 , [1,2,3] is the proper grid for x, and for y=1, [10,20,30] is the proper grid. And similar for z. Everything is linear and even-spaced for demonstration of the problem, but it is not in the

问题 I have a data set that has a list of IDs, year, and income. I am trying to interpolate the yearly values to quarterly values. id = c(2, 2, 2, 3, 3, 3,4,4,4,5,5) year = c(2000, 2001, 2002, 2000,2001,2002, 2000,2001,2002,2000,2002) income = c(20, 24, 26, 30,34,36, 40,46,48,53,56) df = data.frame(id, year, income) For e.g., I am looking to get the values of (interpolated) income for year-quarter 2000Q1, 2000Q2, 2000Q3, 2000Q4, 2001Q1, ... , 2001Q4. So the dataframe would be id,year-quarter,

问题 I want to shift a vector by non-integer shift, linear interpolation seems to be not very accurate so I'm trying to use sinc interpolation by the following code which uses Fourier transform. function y = fshift(x,s) % FSHIFT Fractional circular shift % Syntax: % % >> y = fshift(x,s) % % FSHIFT circularly shifts the elements of vector x by a (possibly % non-integer) number of elements s. FSHIFT works by applying a linear % phase in the spectrum domain and is equivalent to CIRCSHIFT for integer

问题 i'm trying to implement bicubic interpolation; this is a follow-up question to my question:MATLAB vs C++ vs OpenCV - imresize about imresize, so i know openCV doesn't do cubic interpolation like matlab. and i need to get to the same results like matlab. for imresize. so for an example I want to get just the first pixel of my image int* Utilities::MatlabImresize(int* channel,int width, int height, double scale) { double test[4][4] = {{channel[0],channel[1], channel[2], channel[3]}, {channel

问题 im trying to deal with the bicubic image interpolation in c . Therefore i've built this small script. 1. the "resize_image"-function: void resize_image(PPMImage *source_image, PPMImage *destination_image, float scale) { uint8_t sample[3]; int y, x; destination_image->x = (long)((float)(source_image->x)*scale); destination_image->y = (long)((float)(source_image->y)*scale); for (y = 0; y < destination_image->y; y++) { float v = (float)y / (float)(destination_image->y - 1); for (x = 0; x <

问题 I have two arrays x = [0 9.8312 77.1256 117.9810 99.9979]; y = [0 2.7545 4.0433 5.3763 5.0504]; figure; plot(x, y) I want to make more samples of x and y then I interpolated both arrays. I tried this code xi =min(x):.1:max(x); yi = interp1(x,y,xi); figure; plot(xi, yi) but the trajectory is not same as previous plot. Its because the xi is not fluctuating same as x . How should I interpolate both arrays with same trajectory as original one? 回答1: This is an issue because when interpolating,

问题 I would like to extend the functionality provided by Modelica Standard Library's types ExternalCombiTable1D and ExternalCombiTable2D , to implement an N-dimensional (linear) interpolation (with "N" up to at least 4, possibly getting up to 8) on external data tables (saved on txt data files). What would be the best way to do that? 回答1: You might wanna have a look at the current list of ideas for future extensions: https://github.com/modelica/Modelica/issues/1153 回答2: Dassault Systems has

问题 I am trying to create an animated line graph where the line draws out its path from left to right, as in the first scene of this example. I have been closely following the code for mbostock's example, but still am having a couple issues. When I try to run my code, I get an error saying "'d' is undefined", in the attr method inside the draw function shown below: var line = d3.svg.line() .interpolate('linear') .x(function(d,i) {return x(i);}) .y(function(d,i) {return y(d['measures'][i]);});

问题 I'm using a custom ImageView to display a rather large bitmap. The bitmap display is being handled by a matrix that transforms it to what the user sees. I'm trying to implement a "double-tap-to-zoom" but I can't quite get it right. I'm trying to have the image zoom on the point where the user touched with this point ending up in the center of the screen at the end. I worked through a lot of the matrix math and transformations and basically the following transformation is what I need to do

问题 I am writing functions that will calculate 1d interpolations in python using scipy.interpolate function. using help from documentation I wrote 2 different functions for cubic and cubic spline interpolation # calculate cubic interpolation def linear_interpolation(x): linear = interpolate.interp1d(support_x, support_y, 'cubic') return linear(x) # calculate cubic spline interpolation def cubic_spline_interpolation(x): tck = interpolate.splrep(support_x, support_y) return interpolate.splev(x, tck