For questions on writing functions (pure or using Set/SetDelayed) for any purpose, including the features that may be incorporated in those functions, such as options, patterns and conditions.

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72 views

Code check: Force simplified inequalities to be of form `expr > 0`

Simplify is a nice fast function that cleans up simple inequalities. For example: ...
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1answer
69 views

PDF for Normal-Gamma Mixture

The normal-gamma mixture is: ...
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1answer
117 views

Passing function as argument

I've been mucking around with passing functions as arguments to other functions and via trial and error seem to have something that works. I was wondering if someone could have a quick look at some ...
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46 views
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1answer
88 views

How can I write a function which takes another function of a variable and the variable itself as arguments and gives a list of critical points?

This is an exercise from Power Programming with Mathematica by Wagner. I need a function which takes a function and a variable as arguments, like this: critpts[f_,x_]:= and then on the rhs I've got ...
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1answer
56 views

Overloading ClearAll[] to take no arguments

I use the command ClearAll["Global`*"] so much that I thought it would be nice to have a function that called it. Since by default ClearAll requires an ...
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1answer
137 views

Requiring NumericQ in Pure Function

Potential duplicate, but doesn't seem to solve my problem: Using patterns in pure functions I have a function that returns an InterpolatingFunction, and it works ...
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2answers
119 views

function of derivative of a function

I know a similar question is answered somewhere, but it doesn't work for my case for some reason. I have the following problem in Mathematica. I want to compute f[h[x]]= x^2 + D[h[x],x]. Here, h[x] ...
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1answer
288 views

Plot of a periodic triangular wave

I'm trying to graph the zig-zag function at the top of this page: http://www.math.ubc.ca/~feldman/m321/nondiffble.pdf I have a little bit of experience with Mathematica but not a ton. Any ...
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1answer
184 views

Defining commutation relations with Flat functions

Here is a minimal example of the problem I am having. ...
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2answers
156 views

How can define a set of nested parameters

I would like to know how I to define a function with a nested set of parameters (or whatever you would like to call it). For example, how would I get the following function ...
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1answer
233 views

Calling part of a variable in a user defined function

I have defined a function ...
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1answer
58 views

Min function for functions f1, f2, [closed]

There are several "min" functions in Mathematica. In the "Numerical" category, there is a "Min" function that works on a numerical list. Then there's MinValue for finding the minimum of a whole ...
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1answer
44 views

Why this isn't a valid argument? [duplicate]

I am having truble understanding why F1 produces an error, since both time and velocity are the same kind of object: ...
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2answers
59 views

How to generate commands which are very similar?

I have several data sets that I wish to interpolate and integrate like this: ...
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1answer
66 views

Retrieve XML Tree with only specific XMLElements

I would like to retrieve the XML Tree of a XMLObject with only specific XMLElements. In the help of Mathematica ...
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1answer
58 views

Function taking arbitrary number of arguments

I have a very similar function to that which a solution was provided by kguler, but am unsure as to how to adapt the solution that was given there. That post can be seen here. The adaptation is only ...
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1answer
49 views

Mathematica defines a function as list

This might be a very silly question but i'm defining a function as: \[Chi][AR_] := ((AR^(2) - 1)/(AR^(2) + 1)); which is clearly a scalar function of AR; however ...
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2answers
46 views

Retrieve Options from function other than graphics objects

We can retrieve information about used Options for Graphics via: Options[Plot[Sin[x], {x, 0, 1}], "AspectRatio"] (* {AspectRatio -> 1/GoldenRatio} *) even if ...
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1answer
91 views

The problem (time) caused by ?NumericQ

In here, I asked a related (similar) question. Using ?NumericQ seems have slowed down the entire calculation. But I now have a more serious problem: ...
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1answer
106 views

Why doesn't Thread work in this case?

The following function is supposed to pick the element of the list with highest weight, i.e., with Thread [f[{{a,1},{b,2}}]] it should make the variables ...
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1answer
94 views

Composition of Multivariable function

I am trying to compose functions of xleft, maybe like xleft[xleft[f]] or even higher order. And here is my function: ...
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1answer
225 views

How can I call the R-programming packages in my Mathematica?

I am trying to call the R-programming package called highfrequency in my Mathematica so that I can use its function rCov. I ...
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1answer
87 views

How to form a variable from matrix elements

I have matrix with n rows and 2 columns, say m = {{x11, y12}, {x21, y22}, ..., {xn1, yn2}. Now, I want to form three new variables for example: ...
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1answer
108 views

Changing default behavior of Series to give slightly different SeriesData

I am working with complicated expressions expr that contains the symbolic function f[x] which I know to have a pole at ...
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1answer
404 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 ...
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1answer
53 views

Interpolation function evaluation and timing

Lets define two identical functions $f$ and $g$ in a slightly different way ...
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1answer
152 views

Speeding up a function

This is un updated version of a previous (now deleted) post of mine. I need to marginalize a distribution. I was suggested to use the code in this thread. This works just fine, but the problem is ...
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1answer
96 views

Defining a function with global parameters

What I would like to do in Mathematica is something like f[x_] := a x g[a_] := NIntegrate[f[x], {x, 0, 1}] But then of course I get ...
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1answer
48 views

How to substitue local variables into expression with free variables?

I'm wondering how to do the following: expr = L + R; foo[L_, R_] := expr; foo[1, 2] (* L + R *) and have it substitute the function variables ...
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4answers
105 views

Question about sum and list in a function

I have a list of this form: $ lst =\left\{\left\{q_1,x_1,y_1,z_1\right\},\left\{q_2,x_2,y_2,z_2\right\},\text{...},\left\{q_n,x_n,y_n,z_n\right\}\right\} $ I want to use this list in the function: ...
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1answer
133 views

Module that finds the sum of digits of any given positive integer

How can I make a module that finds the sum of digits of any given positive integer? I use this command F[x_]:= Apply[ Plus, IntegerDigits[x] ] Is there another ...
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1answer
270 views

Part::pspec error returned when using a ListLinePlot ColorFunction variable as list index

In ListLinePlot, I'm attempting to construct my own ColorFunction for coloring points differently based on a third dimension of data not plotted to a specific axis. However, ColorFunction only uses ...
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1answer
116 views

Cannot Plot Output of Solve

I'm trying to plot the output of the following function t2[x_] in ...
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0answers
52 views

function of a function [closed]

I have the following two functions, 'f' and 's': ...
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0answers
60 views

creation a table from a default module [closed]

I have used of bisection method for finding the root of a function: ...
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0answers
42 views

Defining a function with a subscripted head

How can I define a function with subscript? Forexample: f_alpha[x] = 2*x
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0answers
69 views

How to Implement a “Function Object” suitable for NDSolve and Finite Element Method?

I have a bunch of methods that shoud return an expression that behave like a function, i.e. an expression that, when supplied with suitable arguments, evaluate to something. A simple ...
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0answers
74 views

Find algorithm or generator formula with automated procedure and pattern recognition

I am trying to find a generator formula for the discriminant of a polynomial and believe it would be an interesting problem for the Mathematica community to know how to automate evaluation of certain ...
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1answer
52 views

How to modify the output result of an evaluation

For ease of notation, I have defined a function, $f$, that defines the permutation of Bosonic particles such that it has the following properties (the form of $f$ is irrelavent for this question): ...
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0answers
71 views

How to input a dynamically changing parameter in NDSolve? [closed]

I am trying to solve a system of DEs with additional conditions, and one condition depends on a parameter. Let us consider the following example: ...
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0answers
75 views

What are the differences between these functions when used for NMaximize?

In short, the question is how to construct the function you want to optimize? ...
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1answer
80 views

Help creating a simple function

Can someone help me to create a function. The truth I'm new in Mathematica and I don't understand well the way functions work in I. I need a function that animate some rectangles according to a curve ...
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0answers
31 views

How to make Expand work right in a function definition?

This works just fine: Derivative[n_, 1][g][x_, v_] := D[g[x, v], {x, n + 2}]/2 + D[D[g[x, v], x]^2/2, {x, n}]; h = Expand[D[g[x, v], {v, 3}]] I would like to ...
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0answers
108 views

How to create a complex variable from dated list values

Can anyone help me to construct a variable "PI" from values of variable x. Variable x represents a group of two time series rj and ri on equal dates(joined two dated lists with states).Variable x have ...
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1answer
67 views

How to Solve a Sequence in Mathematica [duplicate]

Given the input and the output, how do you interpolate a function in Mathematica? For example if you know that $f(1)=\frac{1}{2}$, $f(2)=\frac{1}{3}$, $f(3)=\frac{1}{4}$,... how would you solve for ...
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1answer
115 views

Why is Return not forcing an exit from my function? [duplicate]

Here is simplified version of my code that exhibits the behavior troubling me: ...
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0answers
52 views

A more efficient way of fitting a non-linear model that returns an entire list?

I have a function that takes two parameters, del and nu, and returns a list npoints long ...
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0answers
26 views

Minimizing roots of a transcendental equations [duplicate]

I'm trying to use the solution of FindRoot with parameters for further calculations. Annoyingly enough it always gives me trouble with replacing the parameters. As an example I'm attaching a simple ...