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

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1
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1answer
171 views

How to define a summation with function calling itself?

I am new to Mathematica. I want to do this f(x)=summation f(t), summation is over t, where 1<=t<=x-1 and mod(x+1,t+1)=1, i.e. when x+1 is divided by t+1, remainder is 1 and f(1)=1. Should i use ...
0
votes
1answer
128 views

Integration of DiracDelta

I just came across the following curiosity and I'm not sure whether it's a bug or just me missing something. Here's a minimal example: I defined the following "function" ...
2
votes
3answers
138 views

Creating a function as a table of derivations

Suppose I have function, which is in fact a list of $n$ functions with $n$ parameters f = {#1 + #2^2 + #3^3, #1^2 + #2^3 + #3^4, #1^3 + #2^4 + #3^5}& I want ...
0
votes
2answers
135 views

How to display output as symbols?

I have this piece of code which populates a matrix following different rules depending on row and column number: ...
3
votes
3answers
513 views

For-loop not working as I expect

I want to do this: When 10 <= t < 130, give t -> 1; When 130 <= t<300, give ...
5
votes
3answers
1k views

cross-correlation with time lag

I have two lists with some data. a={1,2,3,4,5} b={5,4,3,2,1} Now I want to compute the cross correlation of the two lists with a time lag of 1, like it is ...
0
votes
2answers
134 views

Handling output that was returned unevaluated from a function

When evaluating functions, including those described in this post, how do Mathematica users handle values returned from a function that are unevaluated? For example (based on 1): ...
0
votes
2answers
170 views

Define a function on a parameter argument set to zero

Say I have an expression (matrix) that depends on several variables. f= {{a, b+c},{2a-b^2,c^5+a b}} I want to define new matrices with the single parameter ...
0
votes
4answers
261 views

Evaluate function from a table

I want to define list of functions and also use them for evaluation. But this just doesn't work. For example ...
0
votes
1answer
896 views

How to properly substitute values into variables?

I have an array of functions in terms of a[0] through a[n] and I wish to replace the a[]'s with previously calculated values p[0] through p[n], as in below: ...
2
votes
3answers
309 views

find connectivity

Imagine a chain of 20 rings, labeled by 1-20 sequentially. We want to make random size sets of numbers randomly chosen from these 1-20 rings. No duplicate numbers are allowed. Example of a set: ...
12
votes
0answers
286 views

How is the mysterious Raw function used?

I have never seen an example use for the mysterious Raw function: Raw[h, "hexstring"] constructs a raw data object with head h, and with contents ...
1
vote
1answer
261 views

Detecting a nonlinear edge in a 2D point pattern

Following an earlier post here, I have generated a point pattern on the unit square $[0,1]\otimes[0,1]$, which is described by a piecewise constant intensity function constructed so that (in ...
1
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0answers
72 views

Distinction between 2 NETTypeInfo answers

In a NETLink application I checked all the types offered by LoadedNETTypes[] according to the following: ...
0
votes
1answer
192 views

Extract information from function definition returned by DefineDLLFunction

I have an application using DefineDLLFunction whose output is: Function[Null, If[NETLinkDLLPrivatecheckArgCount["DRV_AOVoltageOut", {##1},2], ...
0
votes
2answers
251 views

How to find intervals in the domain corresponding to intervals in the range?

I want to find the intervals for the argument m1 of this function corresponding to the value for the function lying in given intervals of the range: ...
0
votes
1answer
181 views

Please explain this code (contains Append, Do, Coefficient)

I am a graduate student using a past student's Mathematica program. Will someone please explain to me exactly what this piece of code is doing? Specifically the ...
2
votes
2answers
203 views

how to get a linearized curve in some intervals

in below picture I draw a graph base on weight of a controller system against cost function. I want to linearise and divide this curve to for example 5 five intervals. is there any function in ...
3
votes
1answer
127 views

Count the number of sqrt and 4th powers in a function

This is a simple and short question. I have a function which contains a certain number of square roots and 4th powers, lets take this one: ...
2
votes
2answers
186 views

ImageDifference. Is there an ImageSame, or how would one do that?

Is there an inverse to ImageDifference? What in two images are the same?
4
votes
4answers
714 views

Generate random points in a region with higher probability in a sub-region

I am trying to generate random samples of points in the unit square in such a way that points inside a given circle are twice as likely to be selected as points outside of that circle. I tried to ...
1
vote
2answers
157 views
19
votes
5answers
2k views

Moving maximum function?

How can I construct a moving maximum function? For example, if I have a list of 12 values: { 5, 6, 9, 3, 2, 6, 7, 8, 1, 1, 4, 7 } and I want to maximize over 3 ...
-1
votes
1answer
85 views

How to specify a specific range for a loop?

I'm having trouble with setting up a particular range in a loop for my programming. Now I have a defined range of data (not continuous numbers) that needs to be applied in a loop. Since the aim for my ...
0
votes
1answer
146 views

Loop function question [duplicate]

I'm new to Mathematica. Below is the code I have trouble with. ...
1
vote
1answer
90 views

Circumventing the default scoping: Assign a variable inside a function [duplicate]

I'm currently trying very hard to assign a variable inside a function. Therefore I'm using a function like this, which should reassign a predefined variable. ...
0
votes
0answers
59 views

Display functions without dependence?

I'm solving systems of equations with a few different functions of time, t, and so I'm getting output with lots of [t] running around. Is there a way to display these functions without the ...
0
votes
2answers
936 views

Defining a function in terms of matrix elements

Currently trying to use elements from a matrix in defining a function however having some trouble. This is a somewhat simplified version of the problem. Say I have the matrix ...
0
votes
1answer
44 views

Showing result of derivative and other functions [closed]

I have a problem with my Mathematica 7.0 When I write: Derivative[x^2, x] Mathematica returns as result : ...
15
votes
2answers
969 views

Why do certain values in ArcSin not fully evaluate?

This is a continuation of: Why do certain fractional values in TriangleWave not evaluate? The analysis by R.M and rasher revealed that problem to reduce to the behavior of: ...
0
votes
0answers
21 views

Incorporating Built-In Function Options/Parameters into Shorthand [duplicate]

Shorthand syntax provides an alternate way to apply functions and, in many cases, improves readability. A simple example would be ...
1
vote
1answer
205 views

Is linear interpolation applicable here

From my understanding about Linear Interpolation especially of that of Newton's Divided Difference Polynomial, we could get the value of F(x) from the given set of ...
0
votes
1answer
66 views

Extend a function defined for integers to a differentiable function of a real variable

Here is a function that calculates the probability of randomly landing on a Fibonacci number not greater than $n$: ...
9
votes
2answers
783 views

Can you apply the Cellular Automata function to a grid containing numbers?

Im attempting to simulate a simple evacuation model using cellular automata theory.My study aims to determine whether Cellular Automata can effectively represent how people would behave in a fire ...
5
votes
2answers
689 views

How to plot several functions without jumping? (multiple eigenvalues of a system as functions of 2 parameters)

I've been working on this research problem for months with some success by no global/proper solution to the problem. So I have square, Hermitian matrices of various sizes ($8,20,38$ dimensions) with ...
4
votes
0answers
53 views

Precedence of defined functions [duplicate]

When I define functions in Mathematica like: f[x_] := 3 f[x_Integer] := 6 How is the value of f[6] determined? It seems to ...
9
votes
2answers
456 views

Nest , Fold … is there an extension for more than 2 arguments?

Fold is an extension of Nest for 2 arguments. How does one extend this concept to multiple arguments. Here is a trivial example: ...
2
votes
1answer
127 views

Declaration of variables in large Linear Programming model with NMaximize

I want to solve a large LP problem using NMaximize. This is a small instance of my bigger problem: $$max \sum^{4}_{t=1}(\sum^{4}_{c=1} V_{c}*f_{c,t})\\ s.t\quad ...
3
votes
4answers
268 views

Redefine ArcCot to be inverse of range [0, Pi]

Mathematica implements ArcCot function as an inverse to Cot on range [-Pi/2, Pi/2]. I ...
2
votes
1answer
171 views

Piecewise function with user-input interval

I would like define a function g[data,bins,x] which is a piecewise constant function taking value data[[i]] in the range ...
1
vote
2answers
222 views

How to sort Table/Matrix including legend(Labellings)

I want to sort table including its legend for graph I have table similar to M1 M2 M3 1 5 2 3 1 4 4 2 -10 5 7 11 6 -2 1 ...
6
votes
2answers
263 views

Why does PolynomialQ[x^n, x] return False?

From what I can see PolynomialQ will return False whenever some exponent is another variable such as here: ...
1
vote
3answers
215 views

professionalize/optimize my code that calls a function

I have the following construction, which defines a function that I subsequently call in a loop multiple times. I use this very often, but I have never looked into if there is a more professional way ...
6
votes
3answers
394 views

Understanding Function and Variable in Mathematica for beginner [closed]

I'm reading the book of Leonid Shifrin, and I love the way the book explains the core in Mathematica. As everything is an expression, now I understand that, there ...
10
votes
4answers
922 views

Refering to global variables inside modules

How do I refer to global variables inside modules if the same name is used for a local one? In code, I want that ...
1
vote
1answer
213 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
129 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
156 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
89 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 ...