1
vote
1answer
37 views

How to assign a list of subsript?

I want to assign Subscript[C,i] by mapping a specific list. For example, the list is {1,2,3,4}, and I want to assign 1 to C1, 2 to C2, 3 to C3 and 4 to C4. How should I do? Many thanks:)
26
votes
1answer
461 views

Are greek symbols causing different evaluation?

I've updated today to Mathematica 9.0.1.0 from version 8 and found something that absolutely confuses me. Let us define a piecewise function: ...
1
vote
1answer
91 views

Getting error FullSimplify::infd: … simplified to ComplexInfinity

I tried to run the following code: ...
1
vote
1answer
121 views

Equation Simplification in Mathematica

I wonder if the following equation could be further simplified by Mathematica. There are $22$ Integrals involved and many of them are in the range $y_l$ and $y_u$. I would guess that at least those ...
13
votes
4answers
344 views

Replacing parts of a held expression with held parts of another expression

I'm applying the Trott-Strzebonski technique in order to replace inside a held expression. ...
2
votes
1answer
281 views

Finding the optimal teams ranking based on the table of match results

My original question was this: So my task is to score all the possible rankings of the 14 SEC football teams and find the best one, using who won in head-to-head games as the sole criterion ...
13
votes
4answers
609 views

How to make a function with its own options as well as passing options to other functions [duplicate]

I have a function with many of its own options, but I would also like to pass options to subfunctions using the FilterRules function. Here's a simple example: ...
3
votes
1answer
302 views

Mathematica 9, Mavericks, Java

I've been trying to get a clear story regarding the interaction of these three components before upgrading my system from Lion to Mavericks --- I can't afford a Mathematica disaster. What I think is ...
1
vote
1answer
92 views

Using imported data in further calculations

I have quite a lot of data in an Excel file, which I have to use in further calculations. The transformation should map a data point with thre coordinates into a two coordinate result. Example: ...
3
votes
1answer
413 views

Draw grid with points

How would I draw a grid with dots on specified intersections? The image below shows the basic idea: If I wanted to label the grid lines with index numbers or letters, how would I do that?
0
votes
0answers
56 views

Block, With, Module, can anyone help me understand the distinction? [duplicate]

I've been working heavily with Block[] for months in my research so I've read the documentation for the seemingly similar commands With[], Block[], and Module[]. Personally, I've had by far the ...
1
vote
3answers
710 views

How to expand the size of the matrix automatically?

I have a matrix in 2x2 a ={{x, y}, {z, u}} I want to expand this matrix 3x3 b ={{x, y, y}, {z, u, x}, {z, x, u}} 4x4 ...
1
vote
1answer
44 views

Cell seems to be evaluating in exponential time even though it shouldn't

I am trying to implement Newton's method for a given function f[x] and a starting x-value xval. The code should print out each new x-value as it approaches one of the zeroes of the functions. g[x] is ...
2
votes
4answers
711 views

How to calculate the position of a figure in an image?

My question is about recognising soccer players in the pitch. Thanks to Bill S who wrote an excellent script to recognise parts of the players. I found this issue after testing his solution. I will ...
4
votes
2answers
78 views

With command does not behave as expected according to its Attributes

The attributes of the With command are HoldAll which means it should not evaluate its arguments before its starts its business. ...
3
votes
1answer
211 views

Clustering of 2D map, based on similarity in spectra

I have experimental 2D-spectroscopy data, in a format similar to this: ...
5
votes
3answers
466 views

Series coefficients for an infinite sum?

I'm working through Carl Bender's Mathematical Physics lectures on YouTube (which are great fun), and I'd like Mathematica's help solving terms in the perturbation series. It would be convenient if ...
0
votes
1answer
136 views

2 Equations continuous at a point

I want to get continuous point between two equations. My equations are: ...
0
votes
1answer
75 views

How to find all subsets which the total of elements is the same?

I want to find all subsets which the total of elements is the same. For example, Subsets[Range[30], {5}] means all 5-element subsets and the range of each element ...
6
votes
1answer
471 views

Parallel optimization of Markov Chain Monte Carlo

I'm trying to reduce the computation time of a MCMC simulation. Essentially I have a set of particles performing a random walk in a periodic random potential. The particles are independent and every ...
1
vote
2answers
160 views

Problems with importing a .txt file

I have some problems with importing a .txt file as a table. This is the file. I tried importing it with data = Import["data.txt", "Data"] I want to access ...
2
votes
1answer
285 views

Internal Shooting Method of NDSolve in combination with NDSolve`Reinitialize?

To explain my problem, I am trying to extend the BVP problem example from the help that illustrates how to use the shooting method of NDSolve: ...
2
votes
1answer
104 views

Define shifted pdf

I defined a PDF called dist, for example like this one: ...
2
votes
2answers
87 views

How do I get the heading elements from the TableForm option TableHeadings?

The following, table = TableForm[ConstantArray[0, {3, 3}], TableAlignments -> Right, TableHeadings -> {None, {"One", "Two", "Three"}}] generates ...
0
votes
1answer
192 views

Calculate expected value of custom pdf

I've a custom pdf in the sense that it's the convolution of several other PDFs p[t_] := Convolve[p1[x],p2[x],x,t]; Now I want to calculate the expected value of ...
3
votes
1answer
128 views

How do I get the length of held list without evaluating the list?

I used Extract with Hold to retrieve a sublist containing expressions I didn't want evaluating, e.g. ...
5
votes
0answers
132 views

Is there a package or canonical way for writing test harnesses in Mathematica?

I've written a complicated function foo.1 I'd now like to simplify this function's code, and later enhance it with more features. With each change, however, I'd ...
1
vote
4answers
532 views

Finding a number which has the same remainder when dividing certain other numbers

I am having some trouble with formulating my problem in Mathematica for this question: Is there a number greater than 1 which leaves the same remainder when it divides into 1716, 2154, and 4271? ...
2
votes
1answer
130 views

Visualizing how the zeros for this function change as its input parameter changes?

I'm trying to explore how the zeros of a certain parameterized function change as its parameter changes. ...
13
votes
3answers
1k views

Plot Matlab icon

I started to explore this on a whim and hasn't succeeded yet… Some introduction for the icon is found here but I can't understand it very well. (I admit that, though playing with ...
1
vote
2answers
108 views

Cannot Plot Function

I cannot plot this function as I am getting errors. I am not sure what I am doing wrong. Seems to work when $$n \rightarrow 1,$$ but when $$n \rightarrow 2,$$ I get a whole bunch of errors and ...
0
votes
0answers
76 views

Log of a Quaternion

My mathematica Input[In] code: ***q = Quaternion[0.1, 0.2, 0.3, 0.4] t=Log[q] QuaternionQ[t]*** Resepective results[Out] from Mathematica 9.0: ...
1
vote
1answer
156 views

CoordinateTransformData that works for any dimension

The function CoordinateTransformData in Mathematica only works for three dimension. For example, ...
6
votes
2answers
287 views

Numerical Optimization Methods

I am curious if any one has comments on "specific characteristics" of a problem that will deem it to be best solved by a specific optimization method such as ...
7
votes
1answer
225 views

NMinimize go out of bounds on some linear constraints

I'm trying to minimize a non-linear function of four variables with some linear constraints. NMinimize on Mathematica 8 seems to go out of bounds on some constraints giving complex values of the ...
1
vote
1answer
127 views

Poor performance when evaluating double integral of hat functions

I am trying to evaluate a double integral but am having performance issues. First a bit of math I am using a Galerkin like scheme to discretize operators in an equation I am working with. The ...
3
votes
1answer
100 views

Bug with LinearProgramming on Integers?

With Mathematica 7: LinearProgramming[{1, 1}, {{0, 0}, {1, 1}}, {1, 1}, Automatic, Integers] gives wrong result {0,1}. But ...
2
votes
1answer
137 views

Represent more nested dataset with the same color in the PieChart

I have multiple dataset that I want to plot in PieChart, as in PieChart[{{2, 2}, {1, 2, 4}}, ChartLayout -> "Stacked"] Now here is the catch: I want the color ...
2
votes
1answer
189 views

Extra brackets of Position command

Command Position always comes with two extra curly brackets {{}} when it's just one index for the location. I use [[1,1]] in front of my position commands. Is there ...
1
vote
2answers
456 views

How to resolve the duplicate error during interpolation

I have few hundred data points corresponding to an irregular shape closed curve. As the result I have data points that have the same value of y but different values of x. I want to create an ...
0
votes
1answer
536 views

NMinimize to optimize function Module

I am using Nminimize for simulation based optimization. I define the objective function (simulation with a variable "a") as a module to be used in the minimization. ...
10
votes
3answers
391 views

Errors when plotting Exp[-x]/x for large values of x [duplicate]

I am trying to plot a very simple function f[x_]:=Exp[-x]/x on a log-log scale like this LogLogPlot[f[x], {x, 10^(-5), 10^7}] ...
6
votes
2answers
289 views

choosing the fastest way of finding position

I have this list {1,7,8,10} for instance. and a second list which is always smaller or equal to the first one say {10,7}. How ...
0
votes
1answer
140 views

Setting plot size within vector; dynamic slider (two part question)

I have a question about the size of a plot in mathematica. I'm working on some differential equations (a simplified model of heat transfer in a building). I've programmed it so that you can set ...
1
vote
1answer
145 views

A list containing zero elements

I have a list containing zero and nonzero elements. How can I throw away zero elements and just keep non zero ones.
2
votes
2answers
77 views

Finding series expansion in parametric setting

Suppose $y=f(x;p_1,p_2,...)$ and $t=g(x;p_1,p_2,...)$ are given where $p_1,p_2,...$ are some parameters. We want to find a series expansion of $y$ in terms of $t$. Is there a direct command or ...
1
vote
2answers
132 views

Minimizing the maximal residual in mathematica

With this: d1 = 10; d2 = 4; mat = RandomReal[{-1, 1}, {d1, d2}]; vec = RandomReal[{-1, 1}, d1]; LeastSquares[mat, vec] ...
1
vote
0answers
44 views

SQLDateTime from a time column is missing the milliseconds component

Can anyone confirm this? I am using M9.0.1 on win7 64bit connecting to a SQL Server db. When I fetch a datetime column the SQLDateTime objects contain 6 entries, 5 integers and a fractional second ...
5
votes
1answer
2k views

Contracting with Levi-Civita (totally antisymmetric) tensor

I have an array $v_{ijk}$ which is effectively a rank-$3$ tensor with dimensions $3\times3\times3$, and I need to contract it with $e^{ijk}$, i.e. evaluate $v_{ijk} e^{ijk}$ (see Einstein ...
8
votes
5answers
2k views

Something faster than Do loops with AppendTo

I am an "old" programmer used to Fortran and Pascal. I can't get rid of For, Do and While ...

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