interpolation

问题 I am performance testing my iPhone app: // using CATransaction like this goes from 14fps to 19fps [CATransaction begin]; [CATransaction setDisableActions: YES]; // NEG, as coord system is flipped/messed up self.transform = CGAffineTransformMakeRotation(-thetaWheel); [CATransaction commit]; Question: why does disabling core animation's default behavior of interpolating between the old and the new transform matrix give such a performance boost? What could they possibly be doing that could be so

问题 I have written a code that uses griddata interpolation to interpolate points on an irregular grid onto a regular grid. I also creating contour plots for two dependent variables after the interpolation. I am able to generate the line contour and filled contour plots and they also match the images qualitatively that were directly generated from my simulation. But the images are shown in a horizontal orientation and also the quality is not as per my expectation. I want the images to be shown as

问题 This is a interpolation problem: I have a function z=z(x,y) and I know the relationship between x and y like x=f(y,x_0). Here x_0's are starting points of curves on time y=0. Let's assume x_0=[0 1 2] has three values. For each value of x_0, I get a curve in R^2.x1=f1(y),x2=f2(y) and x3=f3(y) and I draw z1,z2,z3 curves in R^3 using (x1,f1), (x2,f2) and (x3,f3). How can I interpolate z1,z2,23 for getting a surface? I will be grateful for any help, mgm 回答1: Using your notation, and some

问题 I'm trying to interpolate the value of a function at a single point from it's nearest neighbors. I have f specified on a meshgrid, [x_grid,y_grid,z_grid] = np.meshgrid(x_range,y_range,z_range) , for which I'd like to find an approximate value of a random point p_rand = (x_rand, y_rand, z_rand) . What is an efficient way to find the indices of that nearest grid points and interpolate it's value? It's in 3D - nearest cube or tetrahedron of points would be fine. 回答1: To expand on the comments of

问题 I have a data set like the following: x= [1, 4, 10] y= [10, 20, 30] ( x and y are value pairs, i.e. (1,10), (4,20), (10,30) ) I would like to fill the x values gaps and get linear interpolated values for y . The linear interpolation should be done between each value pair, i.e. between (1,10) and (4,20) and then again between (4,20) and (10,30) . x= [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] y= [10,?, ?, 20, ?, ?, ?, ?, ?, 30] How can I solve this with MATLAB? Regards, Dennis P.S. My original data set

问题 I'm trying to interpolate two 2-dimensional arrays. The original array is shown in blue in the image below. The second one shown, in red, is the same array in blue but moved up and slightly to the right, and with a handful of points removed from the top right end. I use the same process (see end of question) for interpolating extra points in between the existing ones and I get this result: The second array (in red), now interpolated, is clearly wrong in its lower part. Why is this happening

问题 I'm rewriting a Matlab's code in Python Language. In Matlab code I have this function: gt= interp2(I(:,:,i)',xi,yi,'cubic')'; , where I is a RGB image, xi and yi are 2D matrixes with same shape defining the x and y coordinates. After I set gt(isnan(gt))=0; for the values outside the boundaries. This function runs perfectly on Matlab. In Python I wrote the following code: gt=interpolate.interp2d(x,y,img.T,kind='cubic',fill_value=0) , where x and y are the same as the xi and yi in Matlab, and

问题 I am working on a project of interpolating sample data {(x_i,y_i)} where the input domain for x_i locates in 4D space and output y_i locates in 3D space. I need generate two look up tables for both directions. I managed to generate the 4D -> 3D table. But the 3D -> 4D one is tricky. The sample data are not on regular grid points, and it is not one to one mapping. Is there any known method to treat this situation? I did some search online, but what I found is only for 3D -> 3D mapping, which

问题 hi i have two sets of data taken from two seperate import files which are both being imported into python and have been placed in two seperate lists as follows: list 1 is of the form: (node, x coordinate, y coordinate, z coordinate) example list 1: [[1,0,0,0],[2,1,0,0],[3,0,1,0],[4,1,1,0],[5,0,0,1],[6,1,0,1],[7,0,1,1],[8,1,1,1]] list 2 is in the form: (x coordinate, y coordinate, z coordinate, temperature) example list 2: [[0,0,0,100],[1,0,0,90],[0,1,0,85],[1,1,0,110],[0,0,1,115],[1,0,1,118],

问题 I'm trying to use Boost c++ library for Hermite interpolation, but it's not well documented and I'm not well understand. My case is to calculate y values at some x position from data points such as: X: 0.9, 1.7, 2.55, 3.39... Y: 0.9, 0.8, 0.85, 0.84... And get result with equal x spaces (x space 0.5): X: 0.5, 1.00, 1.5, 2.00, 2.5, 3.0,... Y: 0.8, 0.95, 0.8, 0.85, 0.9, 0.9,... Can boost be helpful for me? I had found more implementations of Hermite in web, but examples and it's result output