Questions on the basic structure of the Mathematica language (Wolfram language) including atomic data types, syntax etc

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14
votes
1answer
210 views

Why won't SparseArray let me store values with the head List?

When you attempt to define a SparseArray with elements that have the head List it complains: ...
0
votes
0answers
35 views

How can I change this function for the better? [duplicate]

I have a function for an lfsr (linear feedback shift register): ...
2
votes
2answers
146 views

Can a pattern examine all partitions of a sequence?

Say I have a list: {a, b, c, d}. I'd like to check that the list has some partition, say {{a, b, c}, {d}} such that all the elements of the partition satisfy a ...
0
votes
1answer
66 views

Getting error Import::chtype when mporting 2D array of images [closed]

Suppose I have images = {{1.jpg, 2.jpg}, {3.jpg, 4.jpg}} Now I try to import all of them at level 2, ...
13
votes
1answer
332 views

Is everything in Mathematica ultimately stored as a rule?

My current understanding about Mathematica is that everything, at the lowest level, ends up as replacement rules. First question: is this true? Second question: does Mathematica "gloss over" these ...
0
votes
1answer
49 views

How to destructure local variables?

Why can't I use this Where[{iw, ih} = ImageDimensions[i], ...] instead of this ...
0
votes
1answer
57 views

Permanently fixing a variable in the function

I need to define a function let's say f[x_, y_] := x^2 + y^2 such that I need to fix one variable (let's take y = a) and to ...
0
votes
2answers
151 views

How to construct a linear feedback shift register

Are there any posts regarding the construction of a LFSR (Linear Feedback Shift Register) in Mathematica? I can't seem to find any and I am not sure how I would construct one.
0
votes
2answers
77 views

Function that creates a table from two lists

I have two lists shown below: list1 = {(0,0,0,0),(0,0,0,1),(0,0,1,0),...,(1,1,1,1)} list2 = {1,5,5,5,...,5} How can I construct a function that outputs a table similar to this: $$\begin{array}{c|c} ...
0
votes
1answer
95 views

Help with functions in Mathematica

Still learning how to do things in Mathematica. I want to make a function that has many parts. Doing this in something such as Java, which I am familiar with, would be simple. In Mathematica I have ...
0
votes
1answer
59 views

Built in function to convert list of numbers into list of binary numbers [closed]

Does Mathematica have a build in way to convert a list of numbers into a list of binary numbers? If not how can this be accomplished?
2
votes
5answers
227 views

Making loop based off what I can say in words

I have a list of values a: {1,4,11,14} I want to print out values that satisfy b(1+a) = 0 mod 15 where b are the values from 0 to 14. The output I am wanting is ...
0
votes
0answers
31 views

How can I remove some bad rules applied as a result of syntax error?

This user is pretty light-weight regarding Mathematica rules and such. I dont know how the following issue was created (some prevous bad syntax in the same session) ...
1
vote
1answer
118 views

Using FindMinimum with matrix input

I define the following function which spits out a number S when I feed it a dxd square matrix: ...
10
votes
1answer
366 views

How to visualize pattern matching process?

I want a function that does the same job like ReplaceRepeated, and can make the matching process visible. I searched the Internet but didn't find any existing code ...
0
votes
0answers
56 views

Using NestList instead of Do [duplicate]

How can I express the following code using NestList: ...
10
votes
1answer
172 views

Copy Built-in function to new name

It is know that some built-in functions are system function and changing their properties may cause trouble. Suppose for example I want to change features of Cases: ...
28
votes
2answers
849 views

Is there a name for #1@#2&?

Why does the pure function # @ #2 & have no name? I'm asking because sometimes I find inelegant to write expressions like ...
14
votes
2answers
437 views

I define a variable as local to a module BUT then the module uses its global value! Why?

I have a question about modules and local variables. Here's my example: h = 5; Module[{a, h}, a[h_]= h^2; a[4]] (*Out[2] = 25*) I expected the module to ...
4
votes
3answers
237 views

Manipulate: How to create custom reset Button automatically?

I have a complex Manipulate with more than 10 controls. Each one has its own default value. I'd like to add a custom button in the control area to reset all ...
17
votes
1answer
382 views

Confused about how Partition works

I have a problem about the padding list about Partition command. For instance, ...
4
votes
1answer
120 views

ControlType -> None Vs. Module inside Manipulate (i.e. making everything local)

I'm building a program on another one made available in the Wolfram Demonstration Project. I've noticed that in the original code (working flawlessly) many variables were made local inside the ...
21
votes
3answers
530 views

Real Numbers in the Wolfram Language

Epilog: Much of the discussion in the answers below revolves around the distinction between Real as a data type and real numbers as a domain or class of numbers (irrespective of the form in which ...
0
votes
1answer
270 views

How do I write nested for-loops?

Looking through the reference.wolfram, I couldn't see an example of how to write a multiple line "for" loop in Mathematica. I need to nest many for-loops in such a way I can do many things in the ...
5
votes
2answers
405 views

Code elegance and compactness. Help needed with Map, Apply

I need some help with code optimization and compactness. I have a set of two-dimensional points and I can use the Mathematica function FindClusters to find 4 clusters. I'd like to plot the points ...
2
votes
0answers
67 views

What was the thought behind the parallel versions of Table, Map, etc..?

There separately named versions of the parallel analogues of Map[] and friends: ...
2
votes
3answers
122 views

Computing a sequence by recurrence

I am trying to create a list where each element of the list is calculated using the sum of all previous elements of the list and also uses the $N$th element of another list. The initial value of the ...
1
vote
1answer
84 views

Computing a Sequence using Recurrence

I posted a similar question earlier today, but unfortunately I realized after several hours that I over-simplified the problem for this forum. There is a very good answer to the Computing a sequence ...
10
votes
2answers
347 views

When must I use the Return function?

In a comment to my answer to this question, QuantumDot asks, "Where can I find more information on when I must use the 'Return' function?". I found this too deep a question to be answered by leaving a ...
2
votes
2answers
103 views

DictionaryLoopkup - pattern specification

I would like to find all Italian words that have a specific pattern of letter repetitions. Actually I'm looking for 6-letters words that have 1 letter repeated 3 times, a second letter repeated two ...
3
votes
1answer
197 views

How can I trans-compile Mathematica into another language?

I'm looking for an exhaustive list of source-to-source compilers to all other languages, if any exist that is.
5
votes
1answer
103 views

Changing the definition of N: unexpected $RecursionLimit::reclim error

I have some objects represented as follows: Object[data, param] data is a list of numbers, ...
82
votes
3answers
3k views

How to make use of Associations?

I have been curious about it for long. Now that Mathematica 10 arrives, I think it's time to ask the question: How the new Association data structure would be used ...
4
votes
1answer
41 views

How to find out which definitions use Temporary symbol?

According to the Documentation, Symbols with attribute Temporary are automatically removed when they are no longer needed. For example: ...
14
votes
3answers
213 views

How do I understand ListCorrelate(contains $\{k_L,k_R\}$) when it works for 2-dimentional data?

Two months ago, I asked a question here And @nikie give me a solution: The intuitive way to understand ListCorrelate is that the kernel is "moved" to every ...
1
vote
0answers
73 views

Concise way to express Table[FactorInteger[300][[n, 2]], {n, 1, Length @ FactorInteger[300]}]

I can get the exponent part of FactorInteger[300] with Table[FactorInteger[300][[n, 2]], {n, 1, Length @ FactorInteger[300]}] ...
37
votes
4answers
629 views

What's the difference between Inactive and HoldForm?

In version 10, Mathematica not only added Inactive / Activate but also highlighted this change in the "New in 10" page (in Core ...
3
votes
2answers
103 views

MapThread problem

I would like to do the following: ...
0
votes
1answer
63 views

What does this Append expression do? [closed]

I have to understand some code. A part of it is written below. Can someone explain to me what it does: ...
9
votes
6answers
375 views

Product of elements of a list

Sum is for functions; Total is for a list. Product is for a function; what is the command ...
9
votes
2answers
124 views

DownValue assignment using Apply

Why does assigning a DownValue using Apply, e.g., ...
2
votes
0answers
31 views

How exactly does ReplaceAll work? [duplicate]

I am not sure if this question has been asked before but anyway, Consider these two examples: ...
5
votes
4answers
200 views

Signed power set of a list

Given {a, b, c, ...} with $n$ elements generate a list with $2^n$ elements. For example, if the list were {a, b, c}, then the ...
0
votes
0answers
94 views

Solution of a set of quadratic congruences (Chinese remainder)

Edit: Please remove this question. I think there are mathematics error in what I am asking. You are welcome to edit the question if you can state the problem correctly. I have a set of quadratic ...
2
votes
1answer
316 views

Dynamic graph construction and visualization (Watts' “Small Worlds” α-model)

I need some help in creating a Mathematica program for building and visualizing Watts' "Small Worlds" α-model. This is a variant of the more known (and much more simple) β-model (also known as ...
5
votes
2answers
152 views

Non sequitur in documentation of MemberQ

Mr.Wizard's question about MemberQ and FreeQ got me to re-read the documentation for those functions. I find I don't understand ...
0
votes
1answer
79 views

Association of pure functions [duplicate]

I've encountered confusing behavior of Association when I try to use it for storing pure functions. For example: as = <|"1" -> # + 1 &|> ...
10
votes
5answers
559 views

Postfix Double Slash Notation with Multiple Parameters [duplicate]

Examples A convenient shorthand that I use frequently is the "double slash" notation to string commands together. For example, I can write: ...
12
votes
2answers
247 views

How to restore function attributes to default

Adding an attribute to a function is easy and clearing attribute is easy also. But I don't know really how to restore the attributes of a function to its defaults. All I do is quit the kernel or close ...
3
votes
1answer
318 views

How to use Mathematica for traditional programming

I am new to the structure of Mathematica. I understand that in the notebooks, one enters the symbolic expressions and evaluates them. But I need to generate some simulated data and do that a few ...