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0 votes
0 answers
44 views

Why do the solutions from the FindMinimum produce a lot of unphysical oscillatory points?

The parameters. Here I mention all the parameters I use in my code including some of the functions that I define for convenience Parameter set-I ...
0 votes
0 answers
23 views

Using a discrete ColorFunction [closed]

I'm finding strange behavior with ColorFunction. Say I want to color a plot to indicate the sign of abscissa (this is a simplification of a more complex plot I'd like to do): ...
  • 1,706
2 votes
1 answer
48 views

Plotting image a set under perspective transformation

I want to plot the following set in Mathematica: $$\{ (x_1, x_2)/x_3 \mid (x_1-3)^2 + (x_2-3)^2 + (x_3 - 3)^2 \leq 1\}.$$ In other words, this set is the output of applying the perspective function $f(...
  • 419
0 votes
1 answer
63 views

Poorly behaved ContourPlot

I am interested in finding the interested in finding the intersections of the curves f1==0,f2==0 and g==0 (defined below). My ...
  • 305
2 votes
0 answers
77 views

How to write 2D finite volume solver in a functional approach?

I'm solving 2D poisson problem of a finite volume problem using TDMA. The solution of the problem is given: \[Phi][x_, y_] := x^2 y + x y^2 + 1 The definitions are ...
  • 41
3 votes
0 answers
85 views

Fast approximations of Lyapunov exponents in Mathematica

I have $x_i$ sampled IID from $\mathcal{D}$=Gaussian in $\mathbb{R}^d$ with 0 mean and diagonal covariance $H=\operatorname{diag}h$ and need to find the largest value of $\alpha$, such that the ...
6 votes
3 answers
230 views

Apply pattern using a Slot (#) to each list element using a second slot

I am trying to find a neat way of applying an operation to each list element, but do not know how to properly use multiple slots or whether it is actually possible to solve this with multiple slots. I ...
3 votes
1 answer
115 views

Troubling using the arnoldi method

I have the following code: The first part is just defining the matrices, the error is at the end of the code. ...
0 votes
0 answers
50 views

How to find output response of filter circuit if transfer function is too complex?

I want to find unit step response of this transfer function. But I think, there is a problem, mathematica is not given any solution. Can anybody give me suggestion how to get the output response? <...
2 votes
0 answers
102 views

Simplify or FullSimplify doesn't work on Gamma function [migrated]

I have this expression: Gamma[n - 0.691 + 2.35 I] Gamma[n - 0.691 - 2.35 I] which returns real values for all $n$. However, neither Simplify nor FullSimplify can ...
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3 votes
1 answer
81 views

Steady state fluid flow for downward flow past an obstacle

I was attempting to simulate fluid flow past a circular obstacle. The following is the code which I used ...
1 vote
0 answers
69 views

Unable to solve Delay PDEs Error in Boussinesq Approximation

I'm trying to solve the set of equations below describing the flow of a pot of water being heated slightly. The equations are 2D axisymmetric in nature. ...
  • 103
0 votes
0 answers
45 views

How can I let each input show its number?

The problem I'm facing is that I want to know number of one input. For example, In[1]:= (...) then I know this is first input, but I found only the first input in a ...
0 votes
0 answers
23 views

Set TeXForm for user-defined functions [duplicate]

I defined a function gamma in short for a long function. Now I have an expression (just an example here) ...
0 votes
0 answers
98 views

Problem with Hypergeometric Function

I am working on the following code, ...
0 votes
1 answer
60 views

How to generate the set of lines orthogonal to the mid points of a non-intersectional polygon

Given a set of N = 10 points that in a known order form a non-intersecting polygon take the line orthogonal to a mid point of a line segment, using the first segment for example, and extract the ...
  • 403
0 votes
0 answers
40 views

How can we calculate an integral when Integrate does not converge? [closed]

I tried to calculate the probability density of a wavefunction, but got not result. Does anyone have an idea of an alternative approach to get the probability density of it? Here are the details: <...
  • 989
3 votes
1 answer
47 views

AceGen/ AceFEM: Wrong number of nodes?

I am trying to create an element T1 (linear triangle) to solve the steady, incompressible Navier-Stokes equations. Therefore, my SMSTemplate command reads as follows ...
0 votes
0 answers
26 views

Does Readlist give maximum its speed?

Trying to understand if ReadList can be seed-up. I have a text file with columns of strings and numbers, some of numbers are in Fortan form. To import that in ...
1 vote
0 answers
36 views

How to keep data/tables stored in Mathematica notebooks for use when reopening the notebook? [duplicate]

When we create a table in Mathematica, can we keep it stored in the Noteboook for use when we reopen the notebook? I know I can export to a CSV or other filetypes and import whenever I need and I know ...
  • 5,061
2 votes
1 answer
163 views

Solving analytical integral

I am trying to solve the following integral \begin{equation} \left[\int_{0}^{t/2}d\tau-\int_{t/2}^{t}d\tau\right]\left[\int_{0}^{t/2}d\tau'e^{-\left|\tau-\tau'\right|/\tau_{c}}-\int_{t/2}^{t}d\tau'e^{-...
  • 573
0 votes
0 answers
43 views

How can I upload a package which is saved locally as a ZIP file to Mathemtica Cloud and Load the package?

I am using the online Mathematica Cloud. I have one complete package(in this case, a group theory-related mathematics package), which is saved locally as a ZIPed folder. The ZIPed folder contains ...
  • 1
1 vote
1 answer
87 views

Periodic boundary condition conflicts with DirichletCondition?

I want to solve a simple diffuse equation in a cylinder. $\nabla\cdot(\hat{c}\nabla\rho_P)=0$ $\rho_P(x,y,\theta)==0,\sqrt{x^2+y^2}=R$ $\rho_P(0,0,\theta)==1,\sqrt{x^2+y^2}=0$ $\rho_P(x,y,2\pi)=\rho_P(...
0 votes
0 answers
28 views

How to plot the input to a state-space closed loop model?

I have a mathematica notebook to build the state-space model of a system from its differential equations, calculate LQR gains and simulate the system response. ...
4 votes
3 answers
295 views

Is there a better way to control "Filling"?

I wrote the following code and it works well; however, along the horizontal axis observe the "reddish" line along the interval [0.25,0.75]. It is coming from the CC = line in the code. Is ...
  • 1,393
0 votes
0 answers
31 views

Can I define relations without explicit transformation rules?

Is there an alternative way to use Mathematica for symbolic algebra, where instead of defining explicit transformation rules into 'canonical form', I can instead 'gently inform' Mathematica about ...
  • 1,079
3 votes
2 answers
82 views

Issue with unit conversion

I am getting an error converting energy unit Pa*m^3 (Pascal * Meters^3) to J (Joules). ...
  • 109
2 votes
4 answers
264 views

Evaluate using Mathematica or otherwise the value of $f'(0)$

If we have$$f(a)=_3F_2\left(\frac{1}{2},\frac{a+1}{2},\frac{a+2}{2}; \frac{a+3}{2},\frac{a+3}{2};1\right)$$ where $a\geq 0$ and $_3F_2$ is the Hypergeometric function with unit argument. Evaluate ...
  • 97
0 votes
0 answers
32 views

Solving 2D Poisson Eq with Dirichlet BC's in Python [closed]

Question: I am trying to solve the following PDE: ...
  • 141
1 vote
1 answer
63 views

How to speedup integration of interpolated function with logarithmized data?

Consider some dataset corresponding to the grid x1, x2, function[x1,x2]: ...
  • 5,112
2 votes
0 answers
54 views

Argument value loss using Listable C-Compiled Function

In my recent studies, I have come across a very strange anomaly with C compiled functions. When I call a function that has the 'Listable' attribute while global variables are accessed through ...
2 votes
2 answers
112 views

Series expansion using binomial theorem in Mathematica

The series expansion of $\displaystyle\left(1-\frac{a}{x}\right)^{1/3}$ using the Binomial theorem is given by $$\displaystyle\left(1-\frac{a}{x}\right)^{1/3}=1-\frac{a}{3x}-\frac{a^{2}}{9x^{2}}-\...
  • 159
3 votes
2 answers
112 views

How to make appear different labels to different point in the same graphic? [closed]

I am having some trouble to make a graph where there are three data points with x-error bars and I wanted to label each point. I managed to make the first label (the purple one) to appear but I didn't ...
0 votes
0 answers
27 views

How to use the OutputResponse function with multiple inputs?

I have a state-space model with 2 inputs and 2 outputs. The documentations of mathematica to obtain the output response define the usage as ...
0 votes
0 answers
37 views

How to set reference value a State-Space Model with simulating the reponse?

I have a mathematica notebook to build the state-space model of a system from its differential equations, calculate LQR gains and simulate the system response. ...
0 votes
0 answers
26 views

NDSolve coupled ODEs with data

If I have a system of coupled ODEs, say { x'[t]=expr1[x,y,z] , y[t]=expr2[x,y,z],with proper initial conditions } , along with a set of data of (y,z) in the whole relevant region we want to study. ...
8 votes
2 answers
1k views

Why does Mathematica take so long to produce this sound?

Mathematica is behaving very slow, but it is not like I could compare, as the speed has always been like this. The following ran in 58.64 seconds. Is this normal? How can I speed it up? ...
2 votes
0 answers
54 views

Mathematica unable to realize simple distributional relationship

I was trying to find the CDF for the following problem: ...
0 votes
0 answers
49 views

Who can share me the Signals and Systems Package? [closed]

Dear friend in this community, Recently, I'm studying Pro. Lutovac's "Filter design for signal processing". Direct running his MMA codes in the book needs an obsolete third-party package SSP(...
4 votes
2 answers
276 views

Solving PDE with Dirichlet, Neumann and Boundary conditions

I am trying to solve the following PDE: $$ u_{xx} + u_{yy} = \begin{cases} - \cos(x) \quad -\pi/2 \leq x \leq \pi/2, \\ 0 \quad \text{otherwise} \end{cases} $$ The domain is $\Omega = [-\pi,\pi] \...
  • 141
2 votes
1 answer
106 views

Another solution to a simple DE given by DSolve: not the one I expected

Consider a simple 2nd-order differential equation with a parameter $a$, which can be solved with DSolve: ...
  • 1,217
0 votes
0 answers
38 views

Efficient evaluation of vector inner products [closed]

I have a situation where I'm trying to quickly evaluate elements of some matrix products. Let $A, B$ be two Hermitian random matrices, and suppose that we have solved the eigenvalue problem for $A$. I ...
  • 647
0 votes
0 answers
34 views

How to set the term transfer rule of the equation? [closed]

In the following cases, the root sign, polynomial and constant terms need to be automatically identified, not manually entered. Ensure the universality of the code.That is to say, change the equation. ...
  • 793
0 votes
0 answers
26 views

is there anyway to solve the IDE? [closed]

I am completely new to matlab or any math softwares.I came up with this equation when trying to model a man walking through a door with a damper and constant resistive torque (not really sure if it is ...
1 vote
0 answers
20 views

How to make the Levi-Civita express the value from the package xAct?

I try to use the package xAct to compute the 1-form field from 3-form field as shown in the picture below. However, the value of Levi-Civita or epsilong does not express. How could I solve this? ...
0 votes
1 answer
38 views

Solving series solution of differential equation

AsymptoticDSolveValue[2x*y''[x] -(3+2x)*y[x] +1 == 0, y[x], {x, 0, 5}], this differential equation command, is not outputting the correct solution. The solution should be like y=C1(1+(1/3)x-(1/6)x^2-(...
5 votes
3 answers
217 views

Plot diagonal lattice path

I'd like to plot lattice paths like RUURUD where R is a step to the right, U is a step above ...
2 votes
1 answer
28 views

Using NMinimize for a real-valued function of complex variables

I am trying to use NMinimize to minimize a real-valued function of complex arguments, with a supplied initial point. This doesn't seem to work well. For example, the following gives errors like "...
0 votes
0 answers
42 views

How to simplify the formula under the quadratic root sign? [duplicate]

The following formula is given: ...
  • 793
0 votes
0 answers
19 views

Smoothening noisy distributions to learn eigenvalue statistics

I have a problem involving random matrices, in which I'm trying to learn properties of their spectral statistics. The problem I'm having can be boiled down to a list management issue, but I will begin ...
  • 647

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