# Tagged Questions

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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### Evaluating a list of randomly sampled triplets with a function of three variables

I'm new to Mathematica. I need to generate a list of 1000 triplets of random numbers {r, p, t}, so that 0 < r < 1, ...
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### Apply If function to FoldList [on hold]

I have defined the following function: cpdz[c0_, m_,s_, r_, t_, n_] := If[c0 > 0, c0*(m*c0\s - (m - 1)*Exp[r*t/n]), c0*Exp[r*t/n]] for s I have a set of ...
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### How to plot a function containing $\pm$ and unlimited solutions $n$? [duplicate]

I have $$y=n\pi\pm\arcsin(\sin(x)), n\in\mathbb{Z}$$ How can one define and plot such a function in Mathematica for multuple $n$ at the same time?
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### Using set of lists in if function? [closed]

I have the following function: a3[m_, C_, St_, Stt_] := If[C > 0, (m*C)/St*Stt, 0] now my input for C, St and Stt are different set of lists. So I tried to ...
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### Nest function with an incremental parameter? [closed]

Usually, if we use the Nest[] command, it nests the function directly as in Nest[f,x,3] ...
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### Pass list title as argument? [duplicate]

I have a function that works with a list and outputs it. Is it possible to also get the name of the list as an argument? Right now my code is ...
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### Defining the Hirota operator

The Hirota $D$-operator (derivative) is mathematically defined as follows: $$D_x^n f\cdot g=\left.\frac{\partial^n}{\partial s ^n} f(x+s)g(x-s)\right|_{s=0}$$ An example of this operator acting on ...
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### Recursion: How can i program this expression?

i have the following expression: Vt[EA_, V0_, Cm_, B_] := EA + (V0 - Cm)*B For EA and Cm ...
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### Create a polynomial of a given degree

In Mathematica, how can I create a polynomial function in given variables of a given degree with unknown coefficents? That is, I am looking for a function ...
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### Can you define “| |” to be the same as “Abs[ ]”? [duplicate]

When calculating the modulus of a complex number in Mathematica, the standard (and probably least-ugly) way of doing it is by using the Abs[ ] function. When doing ...
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### Local modification of built-in command via UpValue

I have a computationally intense function f that returns a matrix. Sometimes only the diagonal is needed, which is faster to compute, thus there's a syntax for f to ...
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### How to make a custom function as inbuilt

I have a custom function like following: ...
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### Defining a function when the variables do not appear explicitly in the definition of the function

I am trying to take the curl of a vector field which is the a product of a scalar field (Psi) and a coordinate vector, {r,Theta,Phi}. After taking the curl I want to calculate the magnitude of the ...
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### Using Solve[ ] inside a Module

I want to use Solve[] inside a Module. If I make the variables solved for local to the module, they are treated differently than ...
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### Grouping/precedence for “/@” operator

This returns errors: {#[[1]],#[[3]]} & /@ {#[[1]],#[[2]],#[[3]]} & /@ {{"A","B","C"},{1,2,3}} Part::partd: Part specification A[[1]] is longer than ...
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### Function with declaration of variables [closed]

Is it possible to create a function with declaration of variables inside. For instance ...
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### How to split text without spaces into list of words? [duplicate]

What is the best approach to a problem like this in Mathematica? I can only manage this: ...
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### Define a function as an evaluated integral [duplicate]

I have the following integral which I evaluate analitically ...
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### Set a minimum threshold value for a function

I have defined the following function in Mathematica al[z_] := (a/((1 + a*(b/(2 Pi))*Log[z/Mz]))) (a and ...
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### Line-crossing Algorithm Implementation (pt. 2) [closed]

This is a continuation of the problem I posted earlier with the line-crossing algorithm that I tried to implement in Mathematica. I took Kuba's suggestion, removing the underscore on everything ...
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### Defined a function but it doesn't seem to work

I'm trying to implement the line-crossing algorithm on Mathematica and I seem to be having trouble getting it to work. More specifically, I would like to know what is causing the function to not ...
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### Defining a function that depends on the length of a number and the $n$-th digit

I have defined the functions F[i][x] for i={1, 2, 3}.. I want to write a number that has only the characters 1, 2, 3, and I want ...
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### How to turn a function's input argument into a new function

I want to write a function via a module that takes a user's input and creates a function from the input within the module. That is something like Input: ...
301 views

### How to check the validity of an option value

I have a user-defined function, func, which takes the following form: func[arg1, arg2, options] Here is the actual code ...
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### Implementing the Cimmino method [closed]

What am I doing wrong? I am trying to implement the Cimmino method, an iterative method for the solution of linear algebraic systems. The final output should be a vector. Here is a description of the ...
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### How to save the caching produced in processing

As my this previous post.I get a custom function which can help me got some function contain a certain option.And I have put it in my "init.m" file. ...
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### Calculate column number from alphabetic column reference in Excel [duplicate]

Here's a fun brain teaser. Can you give me a mathematical equation to calculate the column number of a Microsoft Excel column, given the alphabetic column reference? Let X, Y, & Z represent the ...
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### Lyapunov Exponent as a function of parameter

I am working at Rossler system and I would like to ask you for some help. This system is described by equations: \begin{array}{ll} \dot{x} = -y - z \\ \dot{y} = x + 0.2y \\ \label{eq:UkladRosSP} \dot{...
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### Catch parameter order and error using functional form

Question: Why does this fail? In:= (Catch[#] &)[Throw[17]] ...
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### How to use the built-in function GraphElementData

Very surprise to me.I found this is a built-in function but it is undocumented.Such as this answer's "CurvedArc" and "Curvature",...
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### Multiple output cells, suppressed by semicolon

I'd like to write a function that outputs multiple cells, as in Multiple output cells, but not when the function is called with a semicolon at the end. Any idea how?
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### Filters on image vs data

I was using GaussianFilter and realized that applying it to an array yields a different result from applying it to an image. For instance: ...