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21 views

VectorPlot3D in cylindrical coordinates

I am using VectorPlot3D to plot fluid flows (in the form of a velocity field), however, I go through quite an involved process to convert flows in Cylindrical ...
26 views

Let's suppose I have an expression in cartesian coordinates, involving gradients, such as: F[x,y]:=D[f[x,y],x]/D[f[x,y],y]+D[f[x,y],y,y] f[x,y] Now, I would like ...
50 views

Inverse substitution polar-cartesian

When I have an expression in polar coordinates and I substitute the definition of $r$ and $\phi$, I get the corresponding expression in polar coordinates. I would like to go back and obtain the same ...
114 views

How to extract coordinates {x,y,z} from Raster3D

I want to extract coordinates out of a Raster3D. It is possible to extract coordinates out of an Image3D by using ...
388 views

Integrate to calculate enclosed area

I am trying to 'use an integral in polar coordinates to calculate the area enclosed by this curve': The curve is: r=sin2θ, θ ∈ [0, π] which I believe is already in ...
141 views

How to guarantee the point's position is fixed in the Graphics and Image

SeedRandom[8] plot = ParametricPlot[ Evaluate@BezierFunction[temPoint = RandomReal[{-50, 50}, {5, 2}]][ t], {t, 0, 1}, AxesOrigin -> {0, 0}] We can ...
189 views

Why PolarPlot can have negative $r$?

Suppose a simple equation in Cartesian coordinate: $$(x^2+ y^2)^{3/2} = x y$$ In polar coordinate the equation becomes $r = \cos(\theta) \sin(\theta)$. When I plot both, the one in polar coordinate ...
69 views

A little confused about coordinate conversion

I'm not entirely sure how to convert from spherical coordinates to Cartesian coordinates, I believe the way to do it is by using the following code: ...
99 views

Why is the range from $-\pi$ to $\pi$ in polar coordinates?

When I run this code FromPolarCoordinates /@ {{3/2, \[Pi]/3}, {3/2, (5 \[Pi])/3}} Then I search the documentation of ...
41 views

Changing from Cartesian to polar coordinates in partial differential equation [duplicate]

I have a partial differential equation: $$\left(x^2+y^2\right)\frac{{{\partial ^2}u(x,y)}}{{\partial {x^2}}} + x^2\frac{{{\partial ^2}u(x,y)}}{{\partial {y^2}}}=0$$ How to change from Cartesian to ...
98 views

Angle between two vectors in spherical coordinates [closed]

I have two vectors: H = {1, 0, π/4}; EA = {1, 0, 0}; Which I want to be in {r, Phi, Theta} - which would should give an angle between the two vectors as ...
136 views

Draw Vectors in Spherical Shell and then Animate

I want to draw three vectors inside a spherical shell. One of the vectors will be moving, the others will be stationary. However, the animation is the next step. For now, I would like to get the ...
66 views

ImageForwardTransformation produces strange artifacts

I am trying to manipulate an image in equirectangular projection with ImageForwardTransformation. I want to change the projection's inclination to the ecliptic. For ...
349 views

Map points on a square onto a Torus

I would like to create a 3D torus plot from a 2D graphic. This 2D original plot is a bit complex, and I haven't a clue how could transform it to a torus. The below code, from this article posted on ...
68 views

I have: ...
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Non-rectilinear integration of InterpolatingFunction

Bug introduced in 7 or earlier and persisting through 10.3.1 [CASE:3487737] I have a 2-d array that I would like to resample into a different coordinate system and integrate along one of the new ...
301 views

Coordinate system transformation problem (about Euler angle)

This question comes from the work that constructing the general cylinder by the NURBS. I have implemented the point-set $P_1,P_2,\cdots,P_n$ that in the $O-xyz$ plane, now I want to implement the ...
71 views

Cylindrical Coordinates with NDSolveValue [closed]

Can anyone help me figure out how to set up a solution for NDSolveValue that incorporates the use of Cylindrical Coordinates. I tried using SetCoordinates[Cylindrical] but it is not working (as in it ...
151 views

ListDensityPlot in Polar coordinates with a higher efficiency

I have data like this f[r,theta] and cells number are about 600*600 (uniform mesh) The original data has the property of uniform mesh for ...
368 views

Using Grad, Div, etc in polar coordinates

I'm trying to use the newish functions Grad and Div to work with a PDE with circular or spherical symmetry and getting what looks to me like a wrong result. However, I'm not sure of this--perhaps I ...
108 views

Integration of angular distribution along cartesian axis

I am plotting an anisotropy distribution function as color coding on the surface of a unit sphere with this code: ...
187 views

PDB Graphics Options: Opacity and Scale to superimpose on 3D point plot

I am trying to superimpose a pdb file into a 3D plot of points extracted from the pdb model, while making the pdb somewhat transparent for easy viewing of plotted points. My problems are as follows. ...
98 views

Why does a transform from polar coordinates using TransformedField not agree with by-hand calculation?

I have the following (simple) system of ODE's that I wish to express in Cartesian coordinates: \begin{align*} r' &= r(1-r)\\ \theta' &= 1 \end{align*} Working it out by hand, by ...
1k views

Analogue for Maple's dchange - change of variables in differential expressions

Maple owns an interesting function called dchange which can change the variables of differential equations, but there seems to be no such function in Mathematica. ...
227 views

Translating Histogram

SeedRandom[1]; RandomVariate[NormalDistribution[], 100]; Histogram[%, Automatic, "Probability"] The above code produces a histogram like I want to translate ...
251 views

Plot a parametric equation in cylindrical coordinates

I'm looking for a way to plot this parametric equation on cylindrical coordinates. r = e^t theta = t+1 z = e^2t Any help would be appreciated
96 views

Change of variables—Galilean transformation

I have a function of two variables, f[x, y], and I wish to do a Galilean transformation, i.e., y = z - v t, where ...
269 views

Is there an easy way to transform unit vectors from spherical to Cartesian coordinates? [duplicate]

Is there a built-in function on Mathematica that will transform unit vectors from one coordinate system to another? I have a vector expressed in spherical coordinates, and I would like to find the ...
475 views

How can I define or use a new coordinate system in Mathematica?

I want to use the dipole coordinate system as defined in this paper: http://arxiv.org/abs/physics/0606044 I see that Mathematica can do all kinds of vector analysis using different kinds of ...
165 views

Von Neumann's method to generate points uniformly distributed on a region of a n-sphere surface

I am trying to generate points uniformly distributed on a region of a single n-sphere surface (all angles in hyperspheric coordinates are between 0 and Pi/2). I decided to use von Neumann's method ...