Linked Questions

2
votes
3answers
64 views

Performing iterated integrals

I would like to define a function $f_n(x)$ and plot it with Manipulate. The function is defined by $$ f_{n+1}(x)=\frac{1}{\int_0^1(f_n(x'))^2dx'}\left(\int_0^xf_n(x'...
3
votes
2answers
180 views

What is the point of tagset /:? [duplicate]

I'm teaching myself Mathematica and came across tagset. So I followed the example in the link, but seem to be missing the point. All of the below give me the same answer after assignment: that ...
0
votes
0answers
80 views

How does Wolfram Language implement for enabling symbols to receive various forms of parameters? [duplicate]

How does the official implement a list/tuple of parameters that can be different in type and quantity as a whole? After re-read @Szabolcs's and @MichaelE2's comments. Finally, I accepted the ...
1
vote
0answers
83 views

Understanding TagSetDelayed

I was reading What is the distinction between DownValues, UpValues, SubValues, and OwnValues? and I started to be confused with the part "Upvalues" of the first answer. Some of my confusion comes ...
1
vote
0answers
63 views

What is exactly an element a[i] in mathematica? [duplicate]

I'm confused about the logic behind mathematica programming. We can have function that will be called doing $f[x]$, thus the element $f[x]$ can be seen as the return value of a function taking an ...
1
vote
1answer
230 views

Scope of dummy variables used in defining a function

I define a function and then define another function, using the same name for the dummy variables as I used for the first function. Will Mathematica use the first definition in the second definition? ...
6
votes
2answers
220 views

What makes a pattern more general?

This is a rewording of the question. The original post is below. How come that a pattern for an expression with a specific head is not more specific than a pattern for an expression with a generic ...
0
votes
1answer
238 views

Get imaginary part of symbolic expression [duplicate]

I define ψ1 = Sqrt[Subscript[ρ, 1][t]] E^(I Subscript[θ, 1][t]); ψ2 = Sqrt[Subscript[ρ, 2][t]] E^(I Subscript[θ, 2][t]); and ...
1
vote
0answers
46 views

Multiple Square Bracketed Function definition

I am familiar with the typical way of defining a function--such as f[x_,y_]:=x+y but I have not found a discussion of definitions such as ...
1
vote
1answer
63 views

How do we input powers of indexed variables?

I have tried (a[i])^2 and alternatively (a^2)[i] Apparently both seem to work, but I was wondering what was the right way ...
4
votes
1answer
281 views

How do I get Mathematica to recognize this simplification? (ReplaceAll pattern rule)

I want Mathematica to understand this $$(\sum_{k=0}^n a_k)(\sum_{j=0}^n b_j) = (\sum_{k=0}^n \sum_{j=0}^n a_k b_j)$$ I have tried this ...
0
votes
1answer
1k views

Compute the half width and full width at half maximum (HWHM / FWHM) of a mathematical expression

I have managed to compute the half width at half maximum (HWHM) and full width at half maximum (FWHM) of a sinc function through the code below. ...
1
vote
1answer
367 views

VectorPlot3D of the Electric Field E as Determined from the Potential V

I am new to Mathematica and I am trying to create the electric field $F$ from the electric potential $V$ (using arbitrary distances) and then plot the subsequent vector graph to show that the electric ...
2
votes
1answer
71 views

How to recall set variables in simple Product[] and Sum[] functions?

I'm new to Mathematica but have been trying to write a code that will define new variables based off of variables preset by a user. I'm allowing them to define a variable ...
0
votes
0answers
154 views

table parametric plot ode

I have a series of ODEs I'd like to plot (a double pendulum specifically) Where I'm comparing my own "handwritten" ODE to that of System modelers solutions. This is mostly an exercise to ensure the ...
6
votes
2answers
222 views

WL terminology: evaluate, call, invoke, use, etc

A WL (Mma) program is a sequence of expressions to be evaluated, which generally involves applying commands and functions to actual arguments. What is the accepted terminology for what I think of as ...
1
vote
1answer
442 views

Plot 3D doesn't show anything

Good Evening, I defined a function which is composed of other several functions. Mathematica compiles well but I can't get a plot and I do not understand way. Can anyone help me with the code and ...
4
votes
1answer
264 views

Define scalar quantity that squares to 1?

My equations contain different cases which differ only by some signs. So in order to work with all cases simultaneously, I introduce a placeholder for a sign: s[x] ...
2
votes
1answer
136 views

Why doesn't CloudDeploy work in my desktop

I have difficulty in making CloudDeploy in my desktop. Does anyone know why ? Thanks Here is what I see: Here is the code if someone would like to test ...
0
votes
1answer
236 views

How to map a function over a dimension in a matrix? [closed]

I have a function g[x,r] yielding a 3x1 vector, where x is a ...
5
votes
2answers
122 views

Custom opaque operator with custom axioms?

Is there any way to define a custom opaque operator/function in Mathematica that satisfies custom axioms, so that the Mathematica engine can perform simplifications using those axioms? For example, ...
1
vote
2answers
143 views

How to define a function whose argument is in the replace list?

As a simplified example: In[780]:= f[x_] := a /. {a -> x}; f[1] Out[781]= 1 This yields the correct result. But ...
7
votes
2answers
297 views

Apply ToString to a list of variables [duplicate]

I have data1 = {1, 1}; data2 = {2, 2}; datalist = {data1, data2}; I want to create a string list based on the variable names inside ...
8
votes
1answer
1k views

Difference between variables and functions

Forgive me if this question is very basic; I've learned Mathematica mostly by example. In most programming languages, there is a clear distinction between variables and functions: variables hold ...
0
votes
0answers
39 views

Can I add options for my function? [duplicate]

...
2
votes
0answers
92 views

Does Mathematica have a method for achieving the same goals that Aspect Oriented Programming does?

I imagine that this question has been asked before, yet I'm not able to find an answer using the form of the question I believe might be asked. Is there a mechanism for duplicating the ...
2
votes
1answer
271 views

Syntax f[x_][y_]

Need to understand the principle of the distinction between f[x_,y_] and f[x_][y_] It seems also that z[x_, y_][a_, b_, c_][α_, β_] := a (x + y)^b + c/(α-β) ...
2
votes
1answer
147 views

Clearing Problem with DSolve [duplicate]

Consider: This is a classic mistake (using a single equal sign) that has been discussed on Mathematica Stack Exchange before. I know that Clear[Derivative] will cure the problem. However, consider ...
5
votes
0answers
66 views

How to use the symbols in System`Private`? [duplicate]

Looking at Names["SystemPrivate*"] gives: I'd really like to use and look at the code for some of these symbols, e.g. ...
1
vote
0answers
86 views

How can PowerExpand be made to evaluate the ArcTan form that takes two arguments?

Consider c = Cos[phi]; s = Sin[phi]; ArcTan[c, s] // PowerExpand ArcTan[s/c] // PowerExpand which yields ...
0
votes
1answer
58 views

How to erase definition introduced by using Set instead of Equal in Solve [duplicate]

When trying to solve a set of equations, I made a mistake by using = instead of ==. Now when I fixed the mistake, the equation ...
1
vote
0answers
51 views

Creating an indexed set of functions with the indices in the function names [duplicate]

As the titles describes, I want to create a list of functions like the following, where the indices are not in the argument slots: ...
3
votes
0answers
243 views

Measuring Temp on a cubical using heat equation with Neumann and Dirichlet boundary conditions

I'm trying to solve 3D heat equation to understand how the temperature varies with time on cubical. i have mixed boundary conditions: Dirichlet on the bottom surface (constant Temp) Neumann on all the ...
1
vote
0answers
113 views

Pattern for a function of say 2 variables [closed]

How can I specify a pattern for an expression f for which say f[x,y] returns a value, ie is defined as a function taking two ...
2
votes
0answers
149 views

NDeigensystem returns error due to mesh discretization when calculating vibrations of a cantilever

There was an transcription error in the code I provided in a previous post: https://mathematica.stackexchange.com/questions/105713/ndeigensystem-returns-complex-non-hermitian-error-for-the-...
2
votes
1answer
235 views

I want to compute the derivative of Black and Scholes option

Good evening to everybody, my question is about computing the derivative of a Black and Scholes option and to draw it. My code is ...
1
vote
2answers
132 views

I want to plot a list of points with specified t and x[t] coordinates [closed]

I have this code: ...
1
vote
1answer
511 views

NDSolve memory usage [closed]

I am trying to solve numerically a system of linear ODEs with some quickly varying driving functions. The basic command is: ...
11
votes
2answers
2k views

Solve a nonlinear PDE equation with a Neumann boundary condition

I am trying to use Mathematica 10 to solve a PDE $$u_t=u_{xx}+u_{yy}+u(1-u),$$ in the unit disk $(x,y) \in D=\{(x,y):x^2+y^2<1\}$, with the Neumann boundary condtion $$\frac{\partial u}{\partial n}...
19
votes
3answers
883 views

Generating assignments and transforming code inside held forms when generating code

I have been playing with slightly above trivial code manipulations in Mathematica. I thought Mathematica would be great for this kind of work because of rule replacement and expression manipulation, ...
1
vote
0answers
136 views

Solving a set of trigonometric equations [closed]

I've been trying to solve the following equations in order to plot Subscript[θ, 41] with respect to Subscript[θ, 2] from 0 to ...
2
votes
1answer
125 views

Sum of operations involving an arbitrary number of 2D vectors

I need to define an equation stating that the sum of n operations involving n 2D vectors and ...
7
votes
4answers
283 views

Iteration of functions

I'm trying to define a function f, such that f[a_]:=a; f[f[a__]]:=f[a]; Then, I tried to evaluate f[x,y]. Since ...
16
votes
3answers
351 views

Why is the first argument of the SetDelayed evaluated?

In[1]: f=g; In[2]: SetDelayed[f[x_],x^2]; In[3]: ?f Global`f f=g In[4]: ?g Global`g g[x_]:=x^2 However, SetDelayed has the ...
0
votes
0answers
60 views

What makes items with head `Function` different?

I apologize beforehand for the muddleheadedness of this question. It reflects the fact that I'm trying to interpret outward "behaviors" of Mathematica expressions without having any understanding of ...
1
vote
1answer
398 views

Create a function with Dt[x] as a variable

I have a function (for example F[x_]:=Cos[x]). I want to define a function like Fdot[x_,xdot_]:=Dt[F[x]] where xdot represents Dt[x]. For example, to define Fdot one might naivley try Fdot[x_,Dt[...
7
votes
2answers
681 views

Assignments in ParallelDo when using indexed variables

For convenience I use an indexed variables syntax to hold results of long computations for different integer parameters: ...
2
votes
1answer
909 views

Partial derivative of defined function with vector input

Background: Have written a formula for the refractive index for a glass slab (n) that depends on the variables t,a and d. Now I want to calculate for example some sort of error and I'll be needing to ...
0
votes
1answer
96 views

Can we say that “all functions in Mathematica are some kind of pattern-matching-and-replacement procedures”? [duplicate]

Currently I am studying Mathematica programming, and when I study pattern matching and replacement, I find it is quite similar to functions. So can we say "all functions in Mathematica are some kind ...
2
votes
1answer
2k views

What is the meaning of two square brackets in function definition? [duplicate]

I came along the following function definition f[a_, b_, c_][r_] = ... with some function on the right hand side. Is this equivalent to ...

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