Questions on Mathematica's scoping constructs (Block, Module, With, etc.)

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15
votes
2answers
339 views

What is the purpose of Internal`LocalizedBlock?

I have come across the (internal) use of of the function: Internal`LocalizedBlock I am trying to determine its purpose. It seem to behave like ...
5
votes
4answers
286 views

Replacing parts of a matrix

I'm a beginner to Mathematica and to writing scripts in general. I'm currently trying to write a code that will take any element in a matrix higher than a certain threshold value n and set it equal to ...
2
votes
1answer
43 views

Substitution breaking the scope

A novice's problem, perhaps: it seems that /. substitution does weird things to the scope. ...
2
votes
2answers
146 views

Expressions containing globally undefined symbols inside a function where they are defined

Consider the following code. f[a_,b_]:=x; Clear[a,b]; x=a+b; f[1,2] It returns a+b. However, from a certain viewpoint, one ...
1
vote
2answers
91 views

Localised variable shows up as Global [duplicate]

Why does this local variable show up as Global? ?q Information::notfound: Symbol q not found. >> ...
-7
votes
2answers
145 views

Module function corrupts string? [closed]

I have the module who should replace some elements of a matrix with checkboxes ...
2
votes
1answer
65 views

How to protect function variables [duplicate]

I am sure this has been asked before, but I can't seem to find the right solution. I want a function to be the solution to a differential equation ...
5
votes
2answers
212 views

A better way of handling Module output?

I am sure this has been asked before in a way or another. I need to Save or DumpSave some symbols that contain the result of ...
1
vote
1answer
52 views

Global variales, Paralell computation and Limiting notebook's contex

If I limit the context of each notebook: and use parallel computation: ParallelTable[ToExpression["b" <> ToString[j]], {j, 1, 10}] then after ...
9
votes
2answers
211 views

How to assemble and disassemble a function into steps

I've watched many programmers (both novice and expert) write functions in Mathematica and have observed a common behavioral pattern. This pattern has many elements that would be automated and thus ...
0
votes
0answers
102 views

Best practices for breaking up functional blocks?

Say I have a main function that does some job, and I'm only interested in the final result of ans, i.e., the local functions are not important and produce no ...
3
votes
1answer
69 views

Should “counters” used in Do, Table, … within Module be declared as local?

I have little to no understanding of how Mathematica handles scoping, so the question may seem a little bit funny. What is the preferred way: ...
3
votes
2answers
227 views

Strange interaction between Module and ListPlot

Bug introduced in 10.0 and fixed in 10.1 Why is the variable a ending up assigned to {1,2,3} after executing Module[{a}, a=Range[3]; ListPlot[a] ]
1
vote
1answer
183 views

NDSolve inside Module with local variables

I want to use NDSolve within a Module and output the solution at some times. (Mathematica 10) All works fine with global variables (symbols) ...
3
votes
1answer
90 views

Defining a function that prints both the name and value of a variable defined locally within the calling function

To save time when debugging with Print statements, I'd like to define a function -- call it PrintVal -- that prints both the name and value of a variable defined locally within the calling function. ...
6
votes
1answer
292 views

A smarter nested With?

I often find myself writing code that looks a bit like this: ...
3
votes
1answer
113 views

Hiding body of a module or function in mathematica

Is it possible to hide the body of a module or function in MMA? For example I would like to turn this: myModule[]:=[{}, Body of module ] to: ...
2
votes
2answers
82 views

How do I localize an assignment to expression (instead of symbol) within scoping construct?

Is it possible to localize an assignment to an expression (defined via UpSet) instead of a Symbol within a scoping construct? ...
12
votes
1answer
222 views

Temporary variable not removed in Mathematica 10

Bug introduced in 10.0.1 and fixed in 10.0.2 In Mathematica 10, the documentation still states that a symbol with attribute Temporary will automatically be ...
1
vote
2answers
81 views

Assigning to the “local” version of a symbol

Compare Manipulate[c[1] = 1; c[1], {c[1], 0, 1}] with Manipulate[Do[c[i] = 1, {i, 1}]; c[1], {c[1], 0, 1}] The first case ...
4
votes
3answers
247 views

Altering values in Manipulate with dynamically generated controls

I have a Manipulate whose controls are generated based on a parameter in a containing Manipulate: ...
0
votes
2answers
82 views

Use conditional expression inside With

I want to assign a number to an internal variable, depending if a specific option has been given, but it seems to fail. Something like: ...
2
votes
1answer
120 views

Odd problem with Module

I've been having a strange problem with Module. Oddly it seems to be linked to my use of Import and then applying a function such as Flatten to my Import. I pasted images of my code and output ...
1
vote
2answers
67 views

Is there a way to logically test an optional color input inside a module? [duplicate]

Suppose I create a Module that is expected to return a graphic that I will later use in a plotting procedure (e.g., with ...
0
votes
1answer
100 views

Substitution of a function in a differential equation

Suppose we have a differential equation as follows: g[t_] := t/2 m[t_] := t/3 A[t_] := {{g[t], 1}, {1, m[t]}} p'[t] == A[t]. p[t], p[0] == {1, 0} ...
3
votes
1answer
104 views

Evaluating arguments of module (inside compile)

Note: this is a clarification of 2 earlier unanswered questions, Compile issues, scoping and order of evaluation and Optimising a simple computation with vectors . The problem I have a list of ...
2
votes
1answer
116 views

Manipulating parameters in a complex algorithm

I have a complex algorithm that depends on: A wavelet basis A number of sampling points out of a distribution A thresholding value I want to be able to play with different scenarios using ...
3
votes
0answers
102 views

Why is it not allowed to define vectors of variables in a scoping construct?

The following command assigns 1 to a, 2 to b and 3 to c: ...
2
votes
0answers
101 views

Compile issues, scoping and order of evaluation

I have a few questions about compiling functions, which I think are all related to scoping and order of evaluation. I will illustrate them by a minimal example of the problem I have. I'm sorry for ...
0
votes
1answer
68 views

Output a symbol from Module or Block

I have troubles to output an entire symbol, a function in this case, from a module or a block. For instance myf = Block[{f}, f[3] = 33; f[4] = 4; f] Then I want ...
1
vote
0answers
126 views

Building Reusable Custom Controls?

I would like to build an application using Mathematica 10. I would very much like to structure the application for maximum maintainability. To this end I would like to segregate controls and user ...
1
vote
1answer
108 views

Return a local variable from a Module containing a Manipulate

I would like to create a set of custom controls that call Manipulate[] and return the value(s) set during the Manipulate session. I can easily make a version that uses something like: ...
3
votes
1answer
300 views

Implementing local variables of a recursive function with either Module or Block

First, some quick background: I have been eagerly learning Wolfram and Mathematica for two months now, and along the way have written about 250 pages of teaching material that has ballooned into a ...
13
votes
1answer
320 views

Is garbage collection broken in version 10.0.0?

Bug introduced in 10.0.0 and fixed in 10.0.1 In version 10.0.0 under Windows I am observing the following behavior: ...
5
votes
3answers
164 views

Prevent iterator name from being confused with symbol passed into function body

I have a massive amount of code with lots of Table and Sum inside a Module. Each with their ...
2
votes
3answers
99 views

Dependency injection - use a specific implementation of one function within another

Consider... f[x_]:=Body containing h[some args]... g[x_]:=Body containing h[some args]... However I want to define something like... ...
0
votes
0answers
21 views

Trouble picking up package definitions [duplicate]

I open a new notebook and type ClearAll[test]; test[x_] := x + 42; I save it as Temp.nb and also as ...
2
votes
2answers
105 views

How can my Manipulate be aware of a local variable inside a nested Module

I have 3 sets of 5 x-y points: RandomInteger[10, {3, 5, 2}] I want to display only one set of points at a time, and use a slider to move on to show the next ...
1
vote
2answers
345 views

Error with “Newton's method” in Wellin's Mathematica book

In Wellin's Programming with Mathematica book, here's one of his implementations of the Newton method, where the iteration runs until the error tolerance is reached. ...
1
vote
2answers
104 views

why the variable scope is not local when using evaluate to plot multicurve?

I noticed a surprising problem when using evaluate to plot multicurve, "evaluate" function actually consider global variable first, not the local! I can illustrate the problem using the following ...
12
votes
2answers
610 views

Syntax highlighter shows error for Manipulate when it's inside a Block or a Module

I'm putting my new copy of Mathematica 10 through its paces and I noticed a weird change in the colouring scheme that I find very annoying, and I'd like to get some insight into why it's happening. ...
2
votes
1answer
52 views

Is the use of Block to temporarily override definitions inherently unsafe? [duplicate]

This may have been discussed before, if so, please let me know. Consider the following example: x = 5 Dynamic[{Clock[], x}] This will always display the ...
1
vote
1answer
59 views

How can I change the scoping of a pure function returned by a function in a package?

I have written a small Mathematica package that contains a module that solves some differential equation with initial conditions. Suppose that the solution to this differential equation defines some ...
1
vote
0answers
48 views

Settings to disable global scope

I am building a fairly large application in Mathematica, and globally scoped variables are causing issues. I would like globally scoped variables to be out-of-scope for my expressions, except by ...
1
vote
0answers
81 views

How to implement nested With as a single construct using functional programming (Fold)?

It is possible to define my own With construct where each local constant can depend on the previous defined local constants? I wish to replace something like this ...
5
votes
2answers
154 views

Generating EventHandler using Table

I would like to change the edge color of a graph when double clicking on it, the following code works: ...
0
votes
0answers
53 views

Scoping problem with Manipulate [duplicate]

Consider the following simple code: f = Sin[a x]; Manipulate[ Plot[f, {x, 0, 10}], {a, 0, 10}] Manipulate takes f to be ...
3
votes
1answer
96 views

How to localize symbols on the right-hand side of Rule when using ReplaceAll? [duplicate]

I am frustrated by the following: {1, 2, 3.0} /. a_Integer -> a + 1 The a on the left side of the arrow is localized and ...
5
votes
0answers
211 views

Exhaustive examples of variable replacement due to nested scoping constructs

Consider the following examples, where I have replaced dollar signs in the output by a D. ...
8
votes
1answer
113 views

Does the syntax coloring I see indicate a real problem?

I need a behaviour provided by: x = 2; Block[{x = HoldForm[x]}, x] x FrontEnd marks ...