Questions about the use of built-in Mathematica functions, including pure functions.

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1answer
172 views

Perform FindRoots on Function Evaluation Containing RootSearch

I am using Ted Ersek's RootSearch function in Mathematica 9.0 (http://library.wolfram.com/infocenter/Demos/4482/) to create a function that I am using for graphing. ...
1
vote
1answer
108 views

Transform list of inequalities into matrix form $A\ x \leq b$

I have a list of linear inequalities, and I want to get it into the form $A\ x \leq b$; i.e., find the matrix $A$ and the vector $b$. Is there any function in Mathematica that can that can do this?
0
votes
0answers
43 views

Limits of PrimeNu [duplicate]

Is there any way to find distinct prime factors for very large numbers using Prime and/or PrimePi that exceeds the ...
3
votes
0answers
139 views

Do a gauge transformation for a Chern-Simons theory?

Suppose we have the following Lagrangian density: $$ L=\epsilon^{\mu\nu\rho}\big(\sum_a A^a_{\mu}(x) \partial_\nu A^a_{\rho}(x)-\sum_{a,b,c}\frac{1}{3} f^{bca} A^a_{\mu}(x) A^b_{\nu}(x) ...
2
votes
2answers
84 views

`PrimeNu` counting function

Building on this question, what is the most efficient counting function for distinct prime factors? It would obviously be more efficient if Prime and ...
1
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1answer
74 views

Defining functions that reference other values

How could I define a function that references other values? eg a = 2 x; b = 4 k; f[k_, x_] := a^b
0
votes
1answer
190 views

Is it possible to convert expressions containing Root objects to Excel formulas?

I am still a beginner and do not fully understand pure functions and root objects. When I tried to calculate the inverse of a function, Mathematica gave me: ...
8
votes
4answers
355 views

Numerical instability in cosh and sinh - integral functions [duplicate]

I'm trying to calculate the function: CoshIntegral[x] Sinh[x] - Cosh[x] SinhIntegral[x] Unfortunately Mathematica seems to hit a point (x~20) and things become ...
8
votes
2answers
255 views

Automatically compute r[1] = r1; r[2] = r2; …

I have three variables like this, r1 = 4; r2 = 3; r3 = 1; and I want to insert them into a function use them in a function definition like so: ...
4
votes
2answers
235 views

Cleaning up InverseLaplaceTransforms in Mathematica

I am attempting to use Mathematica to model an electrical circuit in the s domain. The circuit contains capacitances and and inductances. I've written a series of equations using Kirchoff's laws to ...
1
vote
2answers
159 views

Add a column to a matrix as a function of the other columns

I was wondering if its possible to add a column to a matrix by a formula that uses all other columns, like this: ...
1
vote
1answer
109 views

Linearity of a function in Mathematica

I have a function which has something like myFunc[q,a state[c,d]] a could be anything, and I want to tell Mathematica that ...
1
vote
1answer
141 views

Function derivatives in arbitrary dimension

I have a higher dimensional function: $$f(x,t)=-\ln(t)-\ln(1-\left\|x\right\|^2-t^2)$$ where $x\in\mathbb{R}^n,~t\in\mathbb{R}$. I want to compute the derivatives with the commands ...
3
votes
3answers
268 views

Prime factor counting function

Is there any way I can speed up this prime factor counting function? (I am looking for all numbers in a range with 3 prime factors (counted with multiplicity).) ...
0
votes
2answers
144 views

How to calculate expected return, row by row in matrix? [closed]

Please help me, I'm writing my project and dont know how to solve this big matrix: I have to compute return row by row: 1st row: (18.32-17.14)/17.14 ; (19.17-18.32)/18.32 .... ...
1
vote
3answers
200 views

Pure function inside another pure function

I have the following working expression: In[15]:= Length[Select[IntegerPartitions[10],First[#1]==5&]] Out[15]= 7 But, instead of using the constant 5 I want ...
6
votes
1answer
476 views

How to type binomial coefficient $\binom{n}{k}$

I know how to type a fraction as you would write a fraction in Mathematica (9). How do you type Binomial[n,k] as $\binom{n}{k}$ in Mathematica? Is there a single ...
6
votes
2answers
132 views

Partial result of aborted evaluation of FullSimplify

When FullSimplify invoked on a large expression, it can run for hours. If I do not have time to wait, and abort the evaluation, I get no result, although, ...
5
votes
3answers
1k views

Make a differentiable smooth sawtooth waveform

So, I am trying to understand the effect of sawtooth waveform on a mechanical system model. For example, a system of a plate and a box on it. And then we try to oscillate the plate. In order to do ...
9
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3answers
234 views
6
votes
2answers
197 views

how recover lost data of coordinates from contourplot of mention data?

I have made Contour Plot for a lot of data, like this ...
1
vote
1answer
197 views

Interpolation of a table with 4 parameters

I have a huge data file which I need to do some analysis on it. The file is built in this way that for each 4 variables, there is a value of the function: ...
16
votes
2answers
3k views

Is there an equivalent to MATLAB's linspace? [duplicate]

Does Mathematica have an equivalent to Matlab's linspace? I want to make a list with "start", "stop" and "number of points". What is the neatest way of doing this?
0
votes
2answers
245 views

Using a table to format a grid

Ok, I can't wrap my head around this because I don't know Mathematica well enough yet, so I'm asking for help, at least a direction to explore in. I have a Grid: ...
-1
votes
2answers
231 views

How can I extract when a select condition is met in a do loop the value of the iterator?

I use the following code to find out the number of consecutive prime numbers using a formula $n^2+n+i$ found out by Euler (starting from n=0): ...
3
votes
3answers
352 views

How would I plot the volume element in cylindrical coordinates?

I have this graph: But it doesn't have a function so I can't just plugin in a function into wolfram or mathematica to plot it. I have these coordinates to make it however: ...
4
votes
1answer
156 views

Volume within parameter space

Imagine a parameter space with variable 0<p<1, 0<e1<1/2 and 0<e2<1/2. ...
4
votes
3answers
504 views

Multiple output cells

Is it possible to have multiple outputs from a single function? For example: In[1]:= x+1 x+2 Out[1]= 1+x Out[2]= 2+x has multiple outputs, how can I ...
4
votes
1answer
189 views

Orthogonalizing without normalizing

Is there a way to make Orthogonalize do the normal Gram-Schmidt procedure without normalizing the result? As far as I've understood this was possible with ...
3
votes
2answers
303 views

How can I iterate my code a 1000 times?

this is my solution to Exercise 5 of http://work.caltech.edu/homework/hw2.pdf Please help me make this more elegant. The exercise is about classifying random Points by a (randomly generated) target ...
5
votes
1answer
70 views

How to bail out from a non-applicable transformation function?

I provide a custom function in TransformationFunctions options of FullSimplify that can do a transformation only for some values ...
6
votes
1answer
229 views

Shortest polygonal path

I'd like to find the shortest distance between some points (every point must be visited), such as between these 3 points: ...
5
votes
0answers
177 views

Strange Integrate behavior (a bug!)

The following two calculations should give the same result. After all, integration is a linear operation. I have pasted the code below in case you want to play with it. ...
0
votes
0answers
54 views

mathematica function autocomplete issue [duplicate]

This is the default function structure prompt from Mathematica 9 This is my own function module ...
3
votes
1answer
620 views

Integral of Lorentzian yields different results depending on when parameter assigments are made

I'm evaluating the integral of a Lorentzian, which I know equals one. First I define the function and evaluate the integral in two slightly different ways. Surprisingly, I do not get the right answer ...
1
vote
0answers
74 views

Decapitating “explicit” and “implicit” heads

This is a follow up to this question. So far, I named "explicit" heads to those that appear explicitly in the expression. For example, f[x] has an explicit head. I ...
9
votes
3answers
726 views

Difference between @ and @@

I am confused by the commands @ and @@. From the documentation, I learnt that @@ is the ...
14
votes
5answers
371 views

Partitioning a list of numbers the Mathematica way

I have two sorted lists, one list will be called the "fences" and the other the "values" Fences could be: $\{1, 5, 9, 14\}$ Values could be $\{-1, 1, 3, 4, 6, 9, 10, 13, 14, 15\}$ I want to ...
2
votes
1answer
93 views

What is the need for function parameters? Many possible inputs

If I have many possible variables related to one another, why do I need to define my function with parameters for plotting? For example, if I have an equation like: ...
1
vote
1answer
205 views

using a Mathematica function to define a new function

I'd like to define a function of three variables which produces a new, named function of a single variable, where this final variable is not a member of the first three. So I'd like something where I ...
4
votes
1answer
334 views

Strange result for the analytic integration leads to Hypergeometric2F1

The integration result for Integrate[1/(r^2 Sqrt[x/r^(4 - 2 \[Gamma]) + 1]), r] is: ...
2
votes
1answer
83 views

Behavior of ValueQ inside a function

The following code Cases[Function[{x}, x + 1], a_?ValueQ :> Hold[a], ∞, Heads -> True] unexpectedly returns {Hold[x + 1]} According to the manual, ...
1
vote
1answer
147 views

How to apply a tensor to a list of arguments

The problem I have is the following: Let C be a list of coordinates, say, C = {x1, x2, ..., xn} and ...
3
votes
1answer
176 views

The UnitStep function and Intervals

For the input UnitStep[Interval[{-4, 5}]] I get Interval[{0, 1}] Why is this not ...
-5
votes
1answer
87 views

Converting function into differential version

I am looking through a journal and I came across a function that I wanted to convert to its differential version using Mathematica. Would anyone be able to get the differential version by using ...
5
votes
1answer
167 views

Reverse engineer a sample value from a CDF

The image below shows the cumulative distribution of a normal distribution with mean = 4 and standard deviation = 1. Notice that if you have a value with a rank of 0.8 (meaning it would be 80th item ...
2
votes
2answers
315 views

Are there Min and Max functions that work properly on Intervals?

Mathematica overloads the Min and Max functions to retrieve the lower and upper bounds of an interval. I need functions that ...
7
votes
1answer
176 views

Understanding FullForm in front end

I want to understand the following effect better (In Mathematica 9) .. Or, maybe, is it a bug? Running the following line FullForm[Subscript[α,β_]] gives as ...
13
votes
1answer
422 views

Two ways of map a function on the list: Which one is faster?

There are 2 ways to make a function listable on the list: Use Map or use SetAttributes. My question is, which one is faster, ...
1
vote
1answer
110 views