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

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2
votes
1answer
94 views

How to explain the behavior of Rule inside these functions [duplicate]

I'm trying to define a function that takes an expression and spits out a pure function involving a replacement rule of that function's variable. An example would be a function ...
0
votes
0answers
24 views

Use FindRoot solution as number in function [duplicate]

I would like to save a number that I gain with FindRoot so that I can use it in another function. I tried: ...
1
vote
1answer
56 views

Remove curly brackets _completely_ to map a function to the elements of a list [duplicate]

Most list manipulations can be done with Flatten, Partition and Take. I didn't managed to ...
4
votes
1answer
100 views

Measuring time complexity of a method

I use ...
-1
votes
1answer
77 views

Find minimum function value in data and give coordinates of minimum

I create with Table an array containing the function value of some function and the n1and ...
1
vote
1answer
120 views

Finding the minimum of a function

I asked this question Mark Minimum Value in DensityPlot. Another question has come up, or better said, a task: Find the minimum of a function. I haven't been able to write the needed code for that, ...
2
votes
1answer
58 views

How to create a numerically “equal” function?

A simple example about what I need to do. For example, I have three functions: t1[x,t] t2[x,t] t3[x,t] and, ...
2
votes
0answers
51 views

Maximizing Large Multivariable Function over Region with Parameter Constraints

Brand new Mathematica user here. I have a complicated function to maximize, and thought I would try software like Mathematica instead of taking derivatives by hand. I found some Mathematica ...
0
votes
2answers
225 views

$RecursionLimit::reclim: Recursion problem

Please, find bellow my original question. Here is all my code: ...
7
votes
3answers
296 views

Does Mathematica have Month Range and Day range?

It is known that CharacterRange["a", "z"] gives list of characters from a to z. Does Mathematica have something similar for weekdays and months of the year? ...
0
votes
1answer
64 views

Problem with Maximize

As $\{p1,p2,p3,p4,p5\}$ represents a probability distribution and $l1,l2$ are the eigenvalues of a stochastic matrix, the function $f$, as defined below, has to be maximized over a certain region. ...
2
votes
3answers
82 views

Problem with InverseFunction of Sqrt

I want to build a table of InverseFunctions, f.e.: ...
4
votes
3answers
196 views

Is it possible to specify which range that slot takes from?

consider this example: ...
3
votes
1answer
192 views

Circular membrane vibration simulation

I'm new in Mathematica and I'm trying to simulate the vibration of a circular membrane for math project but I don't even know how to start. The wave equation describes the displacement of the ...
4
votes
4answers
256 views

How can I get the number of slots in Function?

Suppose that I define f = Function[#1 + #2]; And I want to define a new function, argsNum, so that it returns a number of ...
0
votes
1answer
29 views

Why would this function work only when I make a copy of the variable? [duplicate]

Why would this function work with a copy of the function variable: ...
21
votes
2answers
439 views

Why is Query so much slower than Part?

Time for another of these(1),(2) as yet another new-in-10 function appears to have poor performance compared to older alternatives. This time: Query appears to be ...
2
votes
1answer
88 views

How to generate specific function using BSpline command/

I want to generate an approximation function that fits a curve to points. My goal is to obtain an actual formula. Is this possible with the BSpline function? Using the following code: ...
1
vote
1answer
106 views

Solving a trigonometric equation with one parameter

I have the following equation: 2 a^2 k^2 Sin[b k] - 6 a (k Cos[b k] - Sin[b k]/b) == 0 I set the value of b to 1, and I want ...
10
votes
5answers
291 views

How to prevent function from passing values to slot

For the following example: {#, #} & /@ {1, 2} I am trying to find a method to hold one of the slots (or both ) so that the function do not pass the values to ...
4
votes
1answer
201 views

Use of Strassen's algorithm

Strassen's algorithm is an algorithm for matrix multiplication that is asymptotically faster than the naive one. In practice, the matrices involved have to be quite large before Strassen's algorithm ...
2
votes
1answer
90 views

How to determine Fixed Point of a function? [closed]

A function is defined as f[x_]=Sqrt[1-x^2]. How can I determine the fixed point of f? I've tried this: ...
-2
votes
4answers
171 views

Compare elements in a list

Assume that there are three different points in x-y coordinate like: p1={4, -1}; p2={5, -2}; p3={1, 5}; In order to compare these points to each other in a ...
0
votes
0answers
31 views

How can Mathematica solve 7 equations and want to find 7 variables [duplicate]

I have 7 equations as below * e1 := (1 - a) p Subscript[A, 0] Subscript[s, K ] ! *SubsuperscriptBox[(s), (L), (-a)] = (1 - b) Subscript[B, 0] (1 - Subscript[s, K]) (1 - Subscript[s, ...
0
votes
2answers
79 views

prime-palindromic number selected from a list

I want to find all prime-palindromic numbers up to 5000. Prime-palindromic numbers are numbers that themselves and their reverse digits are both primes. For example, 31 is a prime-palindromic number ...
1
vote
2answers
98 views

An argument pattern that my function can treat as Times[constant, variable]

I want to define a function of two variables, func[f_, g_], such that when it sees a general constant multiplying one of the variables, say ...
7
votes
2answers
129 views

Probable Bug in HighlightMesh with 2D Convex Hulls created via ConvexHullMesh

One nice way to view the new and exciting Mesh objects introduced in Version 10 is by utilizing the function HighlightMesh, so ...
1
vote
0answers
133 views

Speeding Up Image Processing Functions

I am working with stacks of 1024x1024 timelapse microscopy images that I am performing a series of image processing functions on to help segment each image. These functions include ...
4
votes
1answer
70 views

How do I constrain variables to a user-defined domain in ArgMax?

I am trying to ArgMax a function over x, but x is only defined between ...
3
votes
2answers
341 views

Is there a function for nearest power of 2 in Mathematica like nextpow2 in MATLAB?

I am looking for something like nextpow2 in MATLAB like this: P = nextpow2(A) returns the exponents for the smallest powers of two that satisfy $2^P \geq\left|A\right|$.
3
votes
1answer
145 views

why Level does not sort output according to their levels

Consider this example: Level[a + f[x, y^n], {0, Infinity}] (*{a, x, y, n, y^n, f[x, y^n], a + f[x, y^n]}*) Why the output is sorted in this way. why not ...
2
votes
1answer
64 views

About Compile Function

I have a function that take p as a parameter, p is a 2X3X3 list, ( a 2X3X3 list can like { {{2,3},{1,2.},{1,1.}}, {{2,3.},{1,2},{1,1}}, {{2,3},{1,2},{1,1}} } ) the function just as: ...
1
vote
1answer
124 views

Computational complexity of symbolic determinant

I'm using the Det function in Mathematica to compute the determinant of an $n\times n$ matrix $A$ with entries of the form $a+bt$ with $a,b$ integers and $t$ a variable, and I would like to know what ...
0
votes
0answers
68 views

Problems with NMinimize

I have written some functions that take a matrix and find its minimum inner product with a specific set of vectors ...
3
votes
1answer
78 views
7
votes
1answer
244 views

Is there a list of Octave functions mapped to the related Mathematica one? [closed]

I am just wondering if there is a list of the related Mathematica functions that correspond to Octave functions. For example. ones(n) maps to ...
0
votes
0answers
60 views

Trouble outputting Plot

I am trying to solve a system of ODEs and plot them with Manipulate but I keep getting blank outputs. Below is my code: ...
4
votes
0answers
84 views

Make Mathematica show function template's arguments in different lines (i.e. in column) by default?

I feel a bit uncomfortable with Mathematica 10's layout. I mean, I'm impressed how powerful functional programming can be and so on, but it's me or those programs are often just a bunch of nested ...
1
vote
1answer
82 views

Convolving data set with gaussian profile

I have a spectrum looking like List, and I want to convole it with a gaussian of the form PDF[NormalDistribution[μ, σ], x] (where σ also depends on x). The raw ...
6
votes
1answer
155 views

Why is AllTrue much slower than VectorQ?

This seems to be a theme with V10, a new function dedicated to a specific task doesn't live up to expectation performance-wise. Mr. Wizard has already uncovered 2 such functions here and here. So how ...
2
votes
3answers
110 views

Speeding Up Replacing of Labels in Large Matrix?

I am Mathematica novice and am trying to find a fast way to replace labels in some rather large matrices (512x512 or 1024x1024) that have resulted from segmenting images with WatershedComponents or ...
0
votes
2answers
88 views

Collapsing summation

I am trying to write a command to collapse the sum of terms into an expression with summation. Something like ...
19
votes
3answers
612 views

DeleteDuplicatesBy is not performing as I'd hoped. Am I missing something?

Déjà vu: a new-in-v10 function should provide a better solution to an old problem, but my enthusiasm is curbed when I run timings. This time the function is ...
0
votes
1answer
125 views

Plot3D unable to understand input function

I'm attempting to plot the Wigner Function of the Morse Oscillator defined as ...
0
votes
0answers
53 views

deleteduplicates Delete elements of a list [duplicate]

I have a math problem about Mathematica, I am looking help from you. I hope that you could help me. The Math Problem: list= { {0,0,1},{1,0,0},{0,1,0} ,{1,2,3}}; ...
1
vote
1answer
87 views

Using Map in a function definition

I want to calculate the hessian of a matrix. So each element gets replaced by a 2 by 2 matrix. ...
0
votes
0answers
51 views

Is it possible to calculate with declarations only?

simple Example: maximize $u(x), x$ solution would show constraints: $\frac{\partial u(x)}{\partial x} = 0$ $\frac{\partial^2 u(x)}{\partial x} < 0$ etc... or do I always have to explicitly ...
-1
votes
2answers
72 views

How to fix the “Module” function, for implicit funcitons? [closed]

I wanted to make a function which gives the frequencies of a number in a specific list, when I came accros this problem. This is what I tried: ...
33
votes
2answers
702 views

Why is the new PositionIndex horribly slow?

This issue has largely been mitigated in 10.0.1. New timings for the final test below are: ...
11
votes
2answers
211 views

Why doesn't a Composition[] hold its arguments and what can be done about it?

Now that Composition (also RightComposition) has shorthand syntax I am more inclined to use it, however what I feel should be ...