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Questions tagged [4d]

4D involves calculations in four dimensions and typically relates to graphics programming. Use the [4d-database] tag for questions about the 4th Dimension database.

From Wikipedia, as of 5 March 2017‎:

In mathematics, four-dimensional ("4D") is a geometric space with four dimensions. It is typically meant to mean four-dimensional Euclidean space, generalizing the rules of three-dimensional Euclidean space. It has been studied by mathematicians and philosophers or over two centuries, both for its own interest and for the insights it offered mathematicians and related fields.

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How to get an hypersphere center point out of 5 surface points?

I'm trying to implement a voronoi sampler in 4-dimensional space, which should be a quite simple task, but picking a good starting points distribution, which can sometimes generate some quite skewed voronoi cells due to the lack of uniformity in…
Fernando D'Andrea
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Split 4-dimensional np.array into 3-dimensional np.arrays by 4th dimension

My apologies if this has been answered elsewhere. I have searched for two days without luck. It seems like a pretty straightforward problem, though I cannot solve it. I have a 4-dimensional numpy array of shape (40, 320, 320, 8). This array is the…
Ben
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Checking for the intersection of a 4D line segment and a 4D convex polytope

I have two 4D shapes: a polytope composed of two triangles with each side connected to the corresponding side on the other triangle (think triangular prism, but not necessarily straight) and a line segment. I don't need to know where they intersect,…
paper man
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How to plot the fourth variable based on a given x, y and z coordinate framework

I have a numpy array with four columns and several rows. First column is my variable and three others are x, y and z coordinates, respectivly: arr= np.array([[2., 0., 0., 0.], [1., 0., 0., 1.], [2., 0., 1., 0.], …
Ali_d
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Reshape a 3D matrix to 4D matrix in MATLAB

I'm trying to reshape a 3D matrix into 4D. I have a 3D matrix e.g. X with dimensions mxnxf. I want a 4D matrix A, with dimensions mxnx8xk, where k=f/8. I've tried the following using mat2cell but it gives me the error that arguments must be…
ΚΩΝΣΤΑΝΤΙΝΑ ΒΑΤΑΒΑΛΗ
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How do I render a 4D object in openGL utilizing homogenous transforms?

I want to try and make a game that utilises movement through 4D cross sections. I have looked repeatedly, but cannot find any answers that present complete and clear code - the closest i found was [how should i handle (morphing) 4D objects in…
candela
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4D plot with gnuplot

I have large data set arranged in four column in a file like this # X Y Z f 0 0 0 0 1 0 0 0 2 0 0 0 3 0 0 0 4 0 0 0 5 0 0 0 6 0 0 0 7 0 0 0 ... where (x,y,z) is coordinate of each point in 3D mesh (between [0,1] in each direction and each direction…
mehdi_bm
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Pass 4D array to lstm in keras

I have data(X) with a shape of (451, 4, 2, 9) where sample number = 451, series number in time = 4, height (two series) = 2, width (each series has features) = 9. So I have table 2*9 which is distributed over time. The shape of y is (451, 2, 1). my…
Asma Damani
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Concatenate list of numpy 3d tensors into one 4d tensor?

I have list of 3d numpy arrays of different shapes, e.g. (128, 128, 3). Now I want to combine all those arrays into one single 4d tensor which looks like (N, ?, ?, ?), where N is the number of 3d arrays. How do I achieve this with numpy?
Marie M.
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How to represent and read 4D array in Opl Cplex from Excel

How can I represent and read a 4D array from Excel to Opl Cplex? The 3D IBM array link is not helpful, trying to adapt to 4D does not work.
Aline Kl
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3D Spherical Polar Plot, with a 4th Dimension Mapped to Another Variable

First, I have found a few threads on this sort of theme, but none of them seem to quite do what I want, or at least I am having a real brain fart in trying to work it out, so I appreciate others input. I have 4 variables that make up a polar plot,…
Gareth Ward
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How can I add an 2d matrix (aXb) into a 4d tensor (e,a,b,2) from a 3d tensor (e,a,b) with tensorflow?

I have a 3d matrix/tensor, which has the format (1000,250,50) and is an input to my TensorFlow model. The first number/dimension is the sum of my examples (1000). The second is the length (250), and the width is (50). Now I want to add an…
user3352632
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Plotting function with 3 parameters (4d) in R

I want to see how three variables x, y, and z respond to a function f using R. I've searched for R solutions (e.g. rgl using 4d plots) but none seem to allow the input of a function as the fourth variable while allowing manipulation of x, y, and z…
carnecol88
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Match 3D vector within 4D array by interpolation?

I've been trying something new for the sake of learning. I'm trying to get a wavelength from a sRGB. I have all the sRGB to XYZ conversion and a conversion table from XYZ to wavelength - 4dimensional. My problem remains in the last line - which…
Moltenhead
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Two 4D mat mul numpy and should expect output 5D

I want to apply attention weights (5 label) to my convolution with 3 filters, could any help me to do how to apply matmul. Appreciated if you give tensorflow version as well. import numpy as np conv = np.random.randint(10,size=[1,3,2,2], dtype=int)…
user1531248
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