0
votes
1answer
105 views
What is wrong with this Cobweb plot [closed]
Something is wrong with my cobweb plot code but I couldn't figure out where do the mistakes come from.
So basically we have the iterative map $x_n == x_{n-1}^{2} - 3 \mu$. I would like to draw a ...
2
votes
1answer
127 views
Range of stability for iterative map
Using linear stability analysis, I would like to compute the range of stability of the fixed points and the 2-cycles of the following iterative map: $x_n = x_{n-1}^{2} - 3\mu$.
Setting $x = x^{2} - ...
3
votes
2answers
110 views
Why don't these styling rules work when viewed in TableForm?
m = RandomInteger[{-5, 5}, {10, 10}];
m /. {x__, y_ /; y > 0} -> Style[{x, y}, Red]
% // TableForm
When m without style ...
1
vote
2answers
178 views
Doing vector manipulations on Mathematica
This is hopefully a simpler version of this previous unanswered question of mine.
Let me just focus on the two expressions $F_2^{(s)}$ and $F_3^{(s)}$ given in A.3 and A.4 of page 19 of this paper. ...
10
votes
2answers
350 views
Is it possible to use the LevenbergMarquardt algorithm for fitting a black-box residual function?
I have a black-box multiargument multiparametric function of the type SRD[dataPoint_List,params_List] which accepts experimental data along with the parameters of ...
7
votes
0answers
61 views
How to create internally optimized expression for computing with high WorkingPrecision?
I have large dataset and need to fit rather complicated function on it with different values of one of its parameters (this parameter must be fixed in every fit). I use the ...
1
vote
1answer
68 views
Using Manipulate Feature for Two ODE's
So I have not been able to find any examples of the Manipulate feature for two ODE's. I would like to plot a graph of x[t] vs. y[t] and manipulate the initial conditions, v and theta. Thank you very ...
2
votes
1answer
79 views
How to combine SparseArray and If
Because I am dealing with huge matrixes, my computer can not handle it, because of the memory. But, in my matrix, a very small percentage of the elements are non-zero. So I should use SparseArray as ...
0
votes
0answers
54 views
How can I connect to a SQLServer database without login details? [closed]
I create a New Database in MS SQLServer 2012, specifically I didn't mention any Login details. I created tables in that DB.
Now I want to connect with Mathematica. For that purpose I wrote the ...
-1
votes
0answers
61 views
Where can I find description of errors and warnings? [closed]
I am trying to solve numerically quite simple equation using NSolve[]. NSolve writes a warning:
...
0
votes
1answer
339 views
How can I understand the result Mathematica returns from DSolve?
I have solved an ODE using DSolve, but I have a problem with understanding the solution.
In general the solution is in the form:
...
10
votes
2answers
421 views
How do I compute sidereal time and JD?
There was once a package that provided a wide range of functions for computing astronomical information. This package now appears to be out of date; but as near as I can tell, many of the useful ...
4
votes
1answer
146 views
1
vote
0answers
73 views
Nontrivial solutions of equation
Here, I have one problem in finding nontrivial solutions of a system of equations. I want to choose one variable, for example X1 and to get solutions of X2(X1) and X3(X1). It is not difficult when I ...
2
votes
1answer
50 views
Scaling of ChartElements
In attempting to answer this question from @Cam on BubbleCharts with elliptical bubbles, I suggested using separate ...
4
votes
2answers
79 views
3
votes
1answer
78 views
Cannot solve system of linear equation sums?
I cannot get mathematica to solve:
The problematic code:
...
0
votes
0answers
11 views
How to assign values to a function at discrete points? [duplicate]
Suppose we are interested in a function f[x] that is defined only at discrete points:
x = {1.1, 2.1, 3.1, 4.1, 5.1}
We want to ...
34
votes
7answers
916 views
Can one identify the design patterns of Mathematica?
... or are they unnecessary in such a high-level language?
I've been thinking about programming style, coding standards and the like quite a bit lately, the result of my current work on a mixed ...
1
vote
0answers
41 views
12
votes
2answers
156 views
Sharp background image in plot
How do I get rid of blurry transitions between pixels of the background image below. It's the fault of Texture[], previously discussed in this answer.
I haven't ...
5
votes
4answers
178 views
How do I obtain the correct double limit?
The command
Limit[(Sin[x^2] + Sin[y^2])/ (x - y) /. x -> 0, y -> 0]
(*
0
*)
I think that Mathematica finds the iterated limit instead of the double ...
5
votes
0answers
43 views
At what point should MLSetMessageHandler() be called?
I have an Installable MathLink program written in C. I would like to use a custom message handler. At which point in the C source code should I call ...
2
votes
1answer
70 views
Recursion depth exceeded
Below is my code for numerical solving of PDE with Crank Nicolson scheme.
...
1
vote
1answer
64 views
How to get a solution set of a nonlinear system of equations?
I'm trying to find the solution set of {x, y} variables for the following system of equations:
...
6
votes
4answers
2k views
Factoring polynomials to factors involving complex coefficients
I've run into some problems using Factor on polynomials with complex coefficient factors. Reading the documentation it looks like it only factors over the ...
0
votes
1answer
84 views
NDSolve complains about missing derivatives of dependent variables in Mathematica 9
In Mathematica 8
NDSolve[{x[t] == 1, x[0] == 1}, x[t], {t, 0, 10}]
solves fine and returns
...
3
votes
1answer
114 views
Using single replacement rule to convert algebraic expression
I have been trying this problems for hours and cannot find any helpful clues.
How can I convert $Sinh[3\theta]+Sinh[\theta]$ to a rational function of x given $2Sinh[\theta] = x-x^{-1}$ by using only ...
1
vote
2answers
151 views
Translating a “Point-to-Triangle” distance script from MATLAB to Mathematica
Update - Thanks everyone for your responses! After fixing a problem with vector normalization, the code below now works.
I'm a new user, and I was attempting to port some Mathematica code from ...
3
votes
1answer
68 views
Resampling when using image as Texture
How to get sharp pixel boundaries with Texture? I'd like to have only black/white in the example below, no gray.
...
5
votes
0answers
173 views
15
votes
1answer
280 views
The Orbit and Perigee of the Flamsteed comet
Historical context
This year we have the 330-th anniversary of the Battle of Vienna - one of the great formative events of European history, it took place on September 12, 1683.
Kara Mustafa, Grand ...
6
votes
2answers
103 views
Variable scoping problem when mapping over delayed replacement
This is something that got me curious while I was playing around with Mathematica.
Consider the following (contrived) example:
...
2
votes
1answer
78 views
Generating a list of all factorizations
What is the best way to generate a list of all factorizations of some number $n$? I'm quite new to Mathematica so this might be obvious. I have been trying some basic stuff with ...
0
votes
0answers
29 views
Import/Export Cluster Object [duplicate]
I want to export and then import back in a cluster object from Agglomerate. After the import, the imported object does not behave as a cluster - for example, ClusterSplit does not recognize it as a ...
5
votes
3answers
98 views
Applying a function with the HoldAll attribute inside NestList
I'm trying to write an update function, which can be applied to a list and then to NestList it.
As the function has to manipulate the given variable I figured I ...
7
votes
2answers
99 views
1
vote
1answer
135 views
Solve this equation symbolically
I am trying to solve the equation for the quantity r = y/x symbolically:
3/y^4 == 3/x^4 + a/(x + 2 y)^4
with the requirement that we need to perform the ...
11
votes
2answers
248 views
How can I compile this function
I want to simplify my function f1 to f2, but f2 can't be compiled. How can I make it ...
0
votes
0answers
33 views
How could I find the correct values for every array that would lead me to unique summation number for every unique chain? [migrated]
I have 9 arrays, each array has 9 values, I need to get the proper values in every value's position for every array, and that would give my a completely unique summations for every value's chain from ...
3
votes
0answers
45 views
Eureqa Client to connect to Mathematica under Windows
Does there exist a way to use Eureqa software with Mathematica under Windows?
That is, is there a working client to connect to a Eureqa server?
1
vote
2answers
83 views
How to create a 3D curved surface, given some discrete points in space?
I have some 3D point data and I want to create a curved surface with these points, and export the curved surface data (point coordinates) according to points density on the curved surface. How can I ...
2
votes
4answers
148 views
How can I create a list of functions?
Can anyone tell me, how to create a list of functions? I've tried the following code, but it doesn't work.
...
10
votes
1answer
153 views
Modules that initialize themselves on first call
I use a lot of functions that extract a specific data item from a file with many data items. I want these functions to load data (slow) and return the item (fast) on first call, but just return the ...
11
votes
2answers
221 views
Notebook formatting - easier descriptions for equations and results?
When I do computations in mathematica, I generally try to make it readable for myself-in-the-future. This can be a cumbersome task in mathematica, where it often requires me to switch betwee a text ...
-5
votes
0answers
86 views
Extracting points data from a 3D curve surface?
I have a 3D data sets, and I have used it to create a 3D plot, but some of the data points are errors and need to be removed. How I can I remove the bad points from the plot?
...
0
votes
1answer
79 views
How to tell Mathematica to make assumptions? [duplicate]
Say I want to integrate 1/(x^2+a^2) and I want Mathematica to know that $a>0$. What would be the command? Something like:
...
2
votes
1answer
72 views
3rd derivative keyboard shortcut
For a long time i've evaluated D[f[t],{t,3}] to get this power-like derivative thing:
$$f^{(3)}(x)$$
Is it possible to obtain same through an easier keyboard ...
8
votes
2answers
141 views
Adding custom GridLines to the “automatic” ones
I need to add custom (vertical) grid lines to a plot (to a DateListPlot, to be precise). I know there is the option of ...
3
votes
1answer
67 views
Dt acting on symbolic notational forms
This one must be simple, but I can't figure out a decent solution.
Suppose, I have a symbol with a notational form applied to it, say OverHat[A].
Now, if I didn't ...
