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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1answer
126 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
249 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
111 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
69 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
48 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
55 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
71 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
79 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
29 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
107 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
99 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
64 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
98 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
49 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
76 views

How can I add options to functions [closed]

One wish take easy advantage of the packages/codes buildt through our engagement with mathematica. Through building packages I see that I have made several functions which are simple and closely ...
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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 ...
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0answers
68 views

Function behavior based on Head

I'm figuring how to implement a function behavior based on the Head of its argument. I mean ...
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1answer
270 views

Gram Schmidt inner and outer products

I know the Gram-Schmidt orthogonalization generates an orthonormal basis from an arbitrary basis. I need help with: Write a program that inputs a list $\{b_1,\dotsc,b_n\}$ of linearly independent ...
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0answers
40 views

Get pattern from rising numbers [duplicate]

I am no mathematician or math star, yet wondering if there is a formula or a way to calculate what follows: I have series of numbers: ...
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0answers
165 views

Issue with Coefficient command

I'm trying to used the Coefficient command to extract the numerical values in front of a Chebyshev polynomial. I know that there is a numerical way to do this, presented in numerical recipes, which I ...
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0answers
212 views

Positive integrand giving negative answer

I'm integrating a positive function f(t) times sin(t) from 0 to pi/5 and get -38. Actually f is slightly negative for a short time (smallest value ~ -0.0005), but far from enough to explain this. ...
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2answers
404 views

Collatz Tool Box — any speed ups possible?

I have created a tool box for experimenting with the Collatz conjecture. Info here: Wolfram MathWorld and here: Wikipedia The patterns I have found allow us to make the conjecture jump through some ...
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0answers
111 views

How to insert a function into OptionsPattern?

I’ve written a function TableauForm to draw a standard Young Tableau. This problem is related to this one, however, the difficulty is that, a function has to be applied to the list in my case. This ...
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0answers
80 views

How can I compile function with Apply?

For example, I tried to compile this function but Mathematica gives "The only function arguments supported are Times, Plus, or List", I have no a way to compile this. ...
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0answers
45 views

Using anonymous functions instead of module or block. Bad idea? [duplicate]

Here is an example function which returns True if a point p is on an (open) line segment (A, B) assuming that Orientation[A, p, B] returns 0 if the three points are collinear: ...
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0answers
265 views

Return Functions from parallel execution of module

I wrote a module which numerically solves an ODE using NDSolve. The result from this is e.g. either ...
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0answers
88 views

Non Commutative Multiply [duplicate]

Possible Duplicate: Non-commutative symbolic linear algebra I want to multiply two matrices, for example, A = {{e, f}, {g, h}} B = {{a, b}, {c, d}} ...
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2answers
1k views

Why function cannot be defined inside For loop? [closed]

I have a following code (which is simplified version of what I am doing): For[i = 1, i <= 5, i++, f[x_] := Sin[x]^2 Print[{i, f[i]}] ] And the question ...
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1answer
177 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 ...
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3answers
101 views

Using “With” outside a function on its parameters [duplicate]

I am making complex 3d graphics, and to clear up functions, I want to use With to remove a repeated action. This action occurs many times through many functions, so ...
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2answers
146 views

Defining a function as a sum of several Gaussians

I have a function that is a summation of several Gaussians. Working with a 1D Gaussian here, there are 3 variables for each Gaussian: A, ...
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2answers
63 views

Define functions from two lists

I have two lists {G[x_,y_],F[x_,y_],C[x_,y_]} and {x*y-x, 3x+y, x^y} Now I need to define 3 functions ...
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3answers
163 views

How to combine multiple functions into a single function, indexed bya new argument

I have a system of expressions (matrices) which correspond to increasing orders of precision in a theory. These expressions are quite complex (require about 40+ lines of code to produce) and are not ...
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1answer
178 views

A function generating particle-in-a-box eigenfunctions

The function sequence is defined over $[-\frac{L}{2},\frac{L}{2}]$ (all elements are valued 0 outside this interval): $$\psi_n(x)=\begin{cases}\sqrt{2/L}\sin{(\frac{n\pi x}{L})} & n \space even ...
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1answer
125 views

Logic behind Flatten and Append to in Module

I have a list(kicks), and a function(fix). I am aware of the problem using Loop and Append or AppendTo. My question is why does the Flatten produce the desired output. List: ...
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2answers
208 views

Constraining two points, a specified distance apart, to a line

Suppose that I have two points in the xy plane: pt1 and pt2init. pt1 is fixed in space, ...
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2answers
47 views

Defining a function from a list [closed]

I have a list of 49 numbers, and I would like to define a function f such that f(n) is simply the nth number in the list. How can I do this?
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1answer
79 views

Determining whether or not an expression is an integer

I'd like to define a function that controls if a certain number is an integer, rational, algebraic and so far. First, I tried generating a list of those numbers: ...
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3answers
156 views

Clean-up Code / Reduce variables

I'm writing a playing card simulator of sorts, and everything works fine, but some Modules use a disgusting amount of variables. For Example: ...
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2answers
93 views

Elegant way to transform formula with sum into code

I have this formula, and many other which contains sum, I am perfectly able to do the computation over a list, however to do this I need to do it in several manual steps. Therefore, I wonder if there ...
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1answer
102 views

Function giving negative value when it should be positive [closed]

I am trying to evaluate $$\displaystyle J=A\sum_{k=0}^{n-2}(-1)^k{n-2 \choose k}B^{n-2-k}\left(\frac{C_1}{k+n}-\frac{C_2}{k+n+1}+\frac{C_3}{k+n+2}-\frac{2}{k+n+3}\right)$$ in Mathematica as a function ...
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1answer
158 views

Optimizing Chi-square distance between two distribution

I want to program the chi-square between two distribution Xu and Vu with length N. This function is defined as below: Xu and Vu are real and positive. ...
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1answer
86 views

Defining the function of list of parameters

I'm defining the functions in the following way ...
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1answer
118 views

Normalize equation in NDSolve?

I have numerically solved and plotted the solution to the Mathieu equation using NDSolve successfully, as below: ...
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1answer
145 views

Patterns of function-arguments in expressions

I want a function that compares an expression with a specific pattern. The expression has always the following form: ...
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1answer
252 views

How to define a function with different types of arguments by setting conditions on function's domain?

I need help in order to properly define a function of $4$ variables. Given that: ...
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1answer
332 views

Function to marginalize a table over given parameters

Let us say I have generated a table tab with entries {p1,..,pd,chi2[p1,..,pd]} of dimension ...
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1answer
67 views

Have the kernel load a user-defined function by default [duplicate]

I wrote a very simple function that I would like to act as if it were one of the default functions that came with Mathematica, so that you don't have to load or import any package before you make use ...
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1answer
84 views

Given a sequence of expressions, how can I convert them all into functions?

I have a sequence of expressions 1, x, x^2, ..., x^5 I want to define a sequence of functions out of it, what should I do? Namely I want to define a vector of ...