0
votes
1answer
25 views

Multivariate integration of a compicated expression

I have an expression in multiple variables that is something like ...
0
votes
0answers
33 views

Table giving error Part::pkspec1: [on hold]

I am evaluating the following expression: ...
5
votes
2answers
95 views

Inflection point and curvature

Through a coordinates list and then interpolating them I got a $f[x]$. ...
12
votes
1answer
373 views

Gillespie Stochastic Simulation Algorithm

The Gillespie SSA is a Monte Carlo stochastic simulation algorithm to find the trajectory a dynamic system described by a reaction (or interaction) network, e.g. chemical reactions or ecological ...
-1
votes
0answers
60 views

About changing the values of global parameters within a function [on hold]

For the code below: a = 1; b = 2; f[c_, d_] =: Module[{e, f, g, h, ...}, ...]; I have references to a and ...
1
vote
1answer
107 views

How to remove parts of an expression [on hold]

I have an expression where terms Transpose[R].R appear. R is a matrix with the property Transpose[R].R=IdentityMatrix[3]. How ...
1
vote
2answers
44 views

Chains of approximate numeric equalities

Mathematica considers two numbers equal if "at most their last seven binary digits" differ. For example: ...
0
votes
0answers
25 views

Using the `TwoAxisListPlot` Package and `Show` Together

I am using the TwoAxisListPlot package to generate a plot with two y-axes (obviously!). I have made a NonlinearModelFit to one ...
-4
votes
0answers
27 views

How to open and use the blackbody radiation program in Mathematica [on hold]

I am trying to open and plot the blackbody profiles for four different temperatures which are (2000,1000,400,100)K. The y coord runs from 10^-4 to 10^6 and the x coordinate runs from 10^-10 to 10^-4. ...
0
votes
0answers
11 views

plotting quaternary [duplicate]

For more information to draw tetrahedron like figure for my data i again insert my data. I have 4 sets of data in 4 axis (x1,x2,x3,y) x1=0.0557 0.0575 0.0613 0.0656 0.0615 0.0448 0.0488 0.0595 0.0654 ...
0
votes
0answers
33 views

Multivariable non-linear fitting

I have a function called "C" that I know it depends on 6 variable. I have a set of data points, 6 rows by 9 columns, in which in each row only one variable is changing and the rest of the variables ...
2
votes
0answers
83 views

Bug in the “PrincipalValue” method of NIntegrate?

Update As pointed by Emilio Pisanty, one should pay attention to EvaluationMonitor to monitor principal value integration. I update the codes, and find some more ...
1
vote
1answer
46 views

How to set UnitSystem permanently

I would like to set the system of units ($UnitSystem) permanently to "Metric". I know that I can do ...
11
votes
1answer
1k views

1D Euler equations (fluid dynamics) with NDSolve

Is it possible to accurately solve the 1D Euler equations in Mathematica using NDSolve? For example, let us consider the problem given here: http://www.csun.edu/~...
5
votes
1answer
88 views

TreeForm outputs different results for the same inputs but why?

First of all, please look at the below inputs and outputs: ...
5
votes
1answer
69 views

Query or MapAt ragged associations or ignoring Missing values

Related to this question, can functions be mapped to named Keys in ragged lists of Associations? ...
9
votes
2answers
292 views

Remove versus ClearAll

What is the difference between Remove and ClearAll? I thought that "not being recognized by Mathematica", which is the effect ...
0
votes
0answers
33 views

how to find the implicit Cartesian equation from calabi yau threefold?

how to find the implicit Cartesian equation from this parametric form? ...
2
votes
1answer
89 views

difference between FullSimplify and Simplify

I have a problem to dinstinguish the following two mathematica codes, the only difference is the first use FullSimplify and the second is Simplify. but the results are totally different. what is wrong,...
0
votes
0answers
34 views

how to confirm calabi yau threefold is invariant?

i have found a list of eigenspace which are complex number if i used calabi yau below and find 3d equations, it may have 3 variables need to input, does it mean that i input any 3 consecutive of ...
1
vote
2answers
117 views

How to force a replacement in an order that I want?

This is a follow-up to this question. I have a big sum, with lots of terms of the form ...
0
votes
0answers
50 views

Making a histogram with a log scale [on hold]

I am really new in Mathematica. I have a data set and plot it in histogram, Now I prefer to plot it in log scale so it would be shown as a line with a specific slope. My code as related to my ...
2
votes
1answer
40 views
0
votes
1answer
44 views

DSolve with coefficients and assumptions

The command below: DSolve[{s'[t] == l t, s[0] == 0}, {s[t]}, {t, 0, a}] gives the error DSolve::alliv: The function <...
1
vote
1answer
107 views

What is the source of error in the following fitting procedure in Mathematica 8.0?

I am trying to fit the following data with a user-defined model. A priori, we know that this model is supposed to be the best fit for the given data. But, I do not know why I am receiving many error ...
0
votes
2answers
51 views

Quartic function from data [on hold]

I am studying something about interpolation. I have a function that is a power x function (f[x_]:=17000 x^-1.85). From this function I got a list with coordinates ...
0
votes
0answers
231 views

How to find Multiple Maxima/Minima [duplicate]

I am trying to solve a problem that requires finding multiple maxima of a numerical function. So the function generates some numbers that are coming out of an experiment. I tried using NMaximize or ...
1
vote
1answer
140 views
1
vote
2answers
204 views

Incorporating the minimum and maximum of the function in a Dynamic plot

I'm working on my project for class and it's supposed to be a graph that can take functions from the user and display it along with finding the max and min of the graph. But I just don't know how to ...
1
vote
1answer
112 views

Maximising solutions of NDSolve [duplicate]

I have the following system of differential equations ...
4
votes
1answer
136 views

How can I find the greatest of this expression?

I want to find the greatest of the expression $$P=a \sqrt{12-b}+\sqrt{b\left(12+a^2\right)}+66\sqrt{a^2+b+3}-\left(a^2+b\right)^2$$ with $a >0$, $0<b\leq 12$. I tried ...
-1
votes
1answer
197 views

Finding the maximum of a gradient vector

Im trying to find the maximum of my gradient vector G[x,y], I've tried several options including FindMaximumValue, FindMaximum etc. but i couldn't find it. The full function is shown below, any help ...
1
vote
1answer
97 views

Moving the start of a graph to the right, finding maxima in an oscillator

I have the following code written to simulate a driven damped oscillator ...
4
votes
1answer
108 views

Calculate area of apple from image

I want to find area of following apple I want to do something like this: define boundary region of apple apple=... then find area using only ...
1
vote
0answers
29 views

Import[] .obj data with per-vertex colors?

There's a somewhat standard way of including per-vetex color with obj files: Geometric Vertex[edit] A vertex can be specified in a line starting with the letter "v". That is followed by (x,y,z[,...
3
votes
1answer
77 views

Progressive animation of a sequence of points

I have two pieces of code that work. The first produces a list plot: ...
1
vote
1answer
43 views

Simplifying x Conjugate[x]

I am trying to simplify a big expression containing many times terms of the form x Conjugate[x]. While this works for a single term: ...
1
vote
0answers
43 views

Line-crossing Algorithm Implementation (pt. 2)

This is a continuation of the problem I posted earlier with the line-crossing algorithm that I tried to implement in Mathematica. I took Kuba's suggestion, removing the underscore on everything ...
-2
votes
0answers
25 views

What is the differences between parametric plotting with regular plotting? [on hold]

I tried to plot using Plot[x] but sometimes people use ParametricPlot[x] to plot their graph. I just wonder, what is the differences between those two and is there any benefit of any?
3
votes
3answers
244 views

I have a 2D space and I want to make it into a torus to replicate a paper

Suppose we have a 2D grid, divided by cells, and that we assign people to each cell. Each person has 4 neighbors, one in the cell above, another in the cell below, and neighbors in the cells to the ...
0
votes
2answers
66 views

Selecting the maximum value from the results returned by NSolve

I'm trying to select the maximum value from the answers Mathematica 7.0 is getting from a simple basic NSolve algebric equation : ...
0
votes
1answer
45 views
0
votes
1answer
145 views

Trouble solving a system of 2 ODE's with NDSolve

I'm trying to solve a system of two coupled second-order ordinary differential equations using Mathematica's NDSolve. The functions of r that appear in the equations are ...
3
votes
3answers
121 views

Rewriting symbol context?

I have some code that uses a list of replacement rules to inject values (physical constants for different materials) into a more complicated expression. This is convenient since I can tweak the values ...
3
votes
2answers
82 views

Henon Map Fixed Points Plot versus Iterations and Plot of the Map

For the Henon Map: $$ x_{n+1}=y_n+1-αx_n^2, \quad y_{n+1}=β x_n$$ I would like to discover period doubling bifurcations by varying the parameter $α$ and plotting $x_n,y_n$ versus the iterations $n$ of ...
1
vote
1answer
38 views

Do double vertical bars in ConditionalExpression mean 'or'? [on hold]

I have a very simple interpretation question. I think that double vertical bars in a ConditionalExpression given by Mathematica as the result of an integration must mean 'or', but I am hoping to ...
7
votes
3answers
117 views

How can I draw ternary plot by these data?

I have these data and want to draw similar fifures in mathematica. any one can help me? ...
20
votes
1answer
625 views
+50

How to numerically solve a 1-d time-independent Schrödinger equation?

The point is to solve the eigensystem of the given Hamiltonian. I tried ParametricNDSolve combined with FindRoot to search for ...

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