Questions on correct (or improved) formulation of Mathematica code to achieve particular results. Use this tag (not "symbol") for questions about all those odd @@ /@ # & and ~ characters.

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4
votes
2answers
75 views

Why can't I pass in a product of matrices in my modified matrixform? [duplicate]

In attempt to build a function that would work like MatrixForm but would wrap a matrix with brackets, I tried the following function: ...
4
votes
1answer
115 views

Highlight the same symbol throughout notebook

Once I saw people using Matlab use a keystroke shortcut that made all the same symbols as a selected symbol become blue. I am wondering is there is a function in Mathematica that is similar. If so, ...
4
votes
1answer
291 views

Upon opening my notebook, I must evaluate cell for code to work properly

I am new to Mathematica. Once I evaluate the cell containing the code, my Manipulate works as desired; however, if I open the file and do not evaluate the cell, the Manipulate goes haywire. Can ...
4
votes
1answer
329 views

Path queries for tree-structured data

Can anyone suggest documentation or tutorials for developing path queries and indices for (XML-like) tree-structured data? Suppose data is organized hierarchically in key->value pairs, eg: ...
4
votes
1answer
67 views

How to define an expression which is differently evaluated in calculations and printed

Let's say, we have a list: values = {1.2, 0.04, 0.9}; Is it possible to replace 0.04 by some expression, which displays as ...
4
votes
2answers
270 views

Limit won't compute

Does anyone know why the limit: ...
4
votes
1answer
81 views

Constructing an Array from typed expression

I want to produce an array from expressions given by test[one][1] = 3; . . test[one][5] = 7; etc. Normally would use ...
4
votes
1answer
1k views

What do the hashtags represent in the result of Solve, and how should I use them? [duplicate]

There is a function that I'm trying to get the inverse of. My function is a simple polynomial: Tn[T_] := 4/9 T^3/Tc^2 + 5/9 T Now I tried to find ...
4
votes
1answer
101 views

Products of Differential Operators

I have a differential equation defined as the product of operators which I want to expand out into a polynomial in powers of $z\frac{d}{dz}$ $\qquad \prod_{n=1}^p(z\frac{d}{dz}+a_n)$ However when I ...
4
votes
1answer
181 views

DeleteCases vs. DeleteDuplicates for removing points within a critical Euclidean distance

I'm attempting to remove all points in an array which are within a Euclidean distance "ThresDist" of one-another. Using the command: ...
4
votes
1answer
115 views

How do you set an Optional parameter with a global variable on a Function defined in a Package

In a Package I am writing, I'm trying to define a function with an Optional parameter in it that is set to a global variable. ...
4
votes
2answers
163 views

Replacing a function in defined expressions

I'm having a little trouble with substituting functions into an expression. A minimal example is as follows: ...
4
votes
0answers
79 views

Why does FromDigits transpose its argument (sometimes)?

FromDigits /@ Transpose@{{1, 2}, {3, 4}, {5, 6}} == FromDigits @ {{1, 2}, {3, 4}, {5, 6}} (* True *) The only "strange" syntax I've found in the docs is ...
4
votes
0answers
78 views

“\:”; flagged as syntax error

While answering question 94032, I noticed that Mathematica 10.2 flagged "\:" <> IntegerString[62378, 16, 4] with a red bracket, apparently indicating a ...
4
votes
0answers
96 views

Multiple Constrained Sum

I need to perform a multiple summation, that obeys some conditions. This arises in the study of a statistical physics model. q=Exp[-β]. I would like to ask if ...
4
votes
0answers
57 views

String option names for Cells

They seem to be correctly interpreted. I'm asking because of some minor reasons and a major one: NotebookWrite a Cell with WholeCellGroupOpener option I don't know any official confirmation so let ...
4
votes
0answers
243 views

Syntax error for optional pattern, but only in debugger

This expression (explained here by Leonid) evaluates fine unless Evaluation->Debugger is enabled: h[x : (_Integer) : 1] := x Syntax::sntxf: "x:" cannot be ...
4
votes
0answers
110 views

Is there a way to check whether two notebooks share the same variables?

When I code in Mathematica, I often re-use code from old notebooks which fulfilled a specific purpose; for example, one testing for soft matches in strings, or one that identifies outliers on a graph ...
4
votes
0answers
119 views

Proper treatment of roots and powers in Series?

I have the following problem in Mathematica 9 on Linux. I let Mathematica compute the Series expansion: ...
3
votes
5answers
906 views

Using variables in function names

I want to make a list of plots and my functions are named C1, C2... Cn. The command I wish ...
3
votes
4answers
217 views

How can I make a summary of all the commands of Mathematica?

I would like to have a simple way to get summary information about all the many commands built into Mathematica. How could I do this? Is there a site I may refer to?
3
votes
3answers
1k views

Superscript prime symbol

x\[Prime] looks like $x_'$, ugly right? Is there a way to make a symbol with prime to look like $x'$? That's what I'm trying right now: ...
3
votes
3answers
178 views

Is it possible to use infix notation ~ for functions with one argument or more than 2 arguments?

According to a Mathematica textbook, we can write N[x,n] by using infix notation as x ~ N ~ n. How about other functions with ...
3
votes
2answers
186 views

Integrate using \[Esc] int \[Esc]

I like writing integrals symbolically instead of using Integrate[]. I suddenly seem to not be able to do this and am confused. I type \[Esc] int \[Esc] then ...
3
votes
1answer
107 views

Export file with semicolon at the end of line

Is there a rule that tells Mathematica to set a semicolon at the end of each line (except of the last one)? My MWE is: ...
3
votes
1answer
101 views

Is it possible to use a mathematical expression as function name?

This might seem as a silly question, but is it feasible to use a mathematical expression as the name of a function? For example, I'm studying the cross section of Compton scattering and there is a ...
3
votes
1answer
96 views

Syntax Coloring for “Possible Unwanted Assignment” Issue

Apparently Mathematica's syntax coloring engine believes that the second assignment in the following code excerpt (concocted for illustration purposes only) is a "Possible Unwanted Assignment" since ...
3
votes
1answer
186 views

Shortening the syntax {var1, var2} /. # & /@ list

I noticed that I often turn out to have a list of substitutions in the form ...
3
votes
2answers
486 views

Why does the first derivative of a piecewise continuous function have discontinuities?

I have this piecewise continuous function which is also continuously differentiable over time : ...
3
votes
2answers
136 views

Why does the iterator index in Table not work here?

I type the following command line Table[D[#1,varx[[i]]] &,{i,3}] where varx is a vector of dummy variables ...
3
votes
1answer
258 views

Using single replacement rule to convert algebraic expression

I have been trying this problems for hours and cannot find any helpful clues. How can I convert $Sinh[3\theta]+Sinh[\theta]$ to a rational function of x given $2Sinh[\theta] = x-x^{-1}$ by using only ...
3
votes
2answers
2k views

How does one specify Neumann conditions for NDSolve?

I have a series of functions defined in my notebook, and then want to use this to solve a diffusion-reaction type equation. At the moment, something like this works: ...
3
votes
1answer
66 views

Open a pop up window that runs a calculation in loop until it is closed?

How should I construct a code which opens a pop up window, displays a constantly updating image in it and is terminated once the pop up is closed? The constant updating would be an infinite loop of ...
3
votes
1answer
115 views

Dt acting on symbolic notational forms

This one must be simple, but I can't figure out a decent solution. Suppose, I have a symbol with a notational form applied to it, say OverHat[A]. Now, if I didn't ...
3
votes
1answer
111 views

Force ellipsis to print an end of an expression

For pedantic reasons I want to display an infinite sum of fractions in fractional form (i.e. as 1/x not as x^(-1)) with an ellipsis at the end of the expression. I have tried a number of ways and ...
3
votes
1answer
362 views

Explanation on why Compile statement works only if input and output sizes work

I found the following code: Compile[{{m, _Real, 2}}, Fourier[m]][Table[N[i - j], {i, 4}, {j, 4}]] which doesn't work correctly. But the following was posted as a ...
3
votes
1answer
139 views

Differentiating a Dot Product

I apologize if this type of question has been asked before, but a preliminary search turned up nothing. I would like to differentiate dot products. For example, consider taking a derivative with ...
3
votes
1answer
100 views

Binary decision diagrams (BDD) syntax error

I am new here (and to Mathematica) and would like to rebuild a simple binary decision diagram that I found here https://en.wikipedia.org/wiki/Binary_decision_diagram A code has been provided as part ...
3
votes
1answer
120 views

HSQLDB database webserver access

I need a database that runs its connection over http and not tcpip. The "HSQLDB (webserver)" jdbc driver should be able to do just that. The following code launces the webserver but the OpenSQLConnect ...
3
votes
1answer
66 views

Pathological behaviour when evaluating a sum

When I declare the function $f$ as follows: f[n_] := Sum[x/Sum[Sqrt[y], {y, 1, x}], {x, 1, n}]/n the input ...
3
votes
1answer
191 views

Levels and slots

I am struggling with levels and #, if I understand this I think I will be able to grasp the entire concept. ...
3
votes
1answer
138 views

Filtering the elements of an array to split them into two categories

So, I am new to Mathematica, and I am trying to write something that involves taking values from one array and separating them into two different arrays. My code for doing this is: ...
3
votes
1answer
84 views

Why minimization does not work with symbolic array as arguments

If I try to minimize with constraints a function of several variables, with Gamma regularized function involved in the constraints it seems to works, as shown below (this is just a dummy example ...
3
votes
2answers
129 views

Substitution in parameters to “Which”

Why in this expression ...
3
votes
1answer
40 views

Aliases for keys?

The syntactic sugar for alternatives in replacement rules is clean: {a|b|c-> 1, d->2} Are there any analogous shorthands for keys in associations. I want ...
3
votes
1answer
107 views

Local evaluation works, CloudDeploy did not work

I a playing around with my programming cloud account. What I have found, interactive functions often are not working because there are several details that are not implemented into the cloud. So I ...
3
votes
1answer
108 views

Why is ^^ff not the same as ^^ToExpression[“ff”]?

I want to convert a hexadecimal string to a decimal (base 10) number: 16^^ff 16^^ToExpression["ff"] The 1st line returns the correct answer of 255, while the 2nd ...
3
votes
1answer
116 views

How to make InverseFunction work on function defined with restriction on arguments

This example works to define InverseFunction on the first argument of a function ...
3
votes
0answers
80 views
3
votes
0answers
36 views

Java anonymous functions from JLink?

JLink is really great to act on Java objects and access Java static methods. I'm asking myself if there would be a way to have access to a more recent Java syntax that allows anonymous functions, ...