Questions tagged [procedural-programming]
Questions about Mathematica's procedural programming paradigm.
360 questions
3
votes
3
answers
506
views
Using Out (%) with control flow
I make heavy use of Out in Mathematica's notebook environment. When I get a computation to work, it will often be spread across multiple cells and lines with ...
- 1,973
1
vote
3
answers
229
views
Faster way to apply a list of numbers to a list of functions
I'm trying to apply two lists random numbers to a list of lists of functions, retrieve a Boolean result for each application, and test for AND coincidence between results. I have a working method, ...
- 309
1
vote
3
answers
255
views
What is the simplest way to write a GeneralizedDo function?
A GeneralizedDo is supposed to thread over multiple iterators:
...
- 10.4k
6
votes
7
answers
557
views
Loop over array cyclically
Is there any way to make cyclic loop over array without PadLeft,PadRight, ArrayPad?
So ...
- 2,590
4
votes
1
answer
216
views
Optimizing Iterative Computations with Large Ranges in Mathematica
I have an implementation in Mathematica that involves iteratively generating large ranges of values, performing element-wise operations, and calculating a cumulative product followed by a total. While ...
- 590
0
votes
0
answers
166
views
Optimizing a While Loop for High-Precision Computation in Mathematica
Edit: Clarifying the Core Issue
i=x;
While[Abs[p1 - p2] >= p1 tol,
p2 = p1;
p1 += s *= i (mkn + i)/((k1 - i) (n1 - i));
i--;
];
The core of my ...
- 590
1
vote
1
answer
154
views
Translating Python for loops to Mathematica [closed]
I have the following snippet written in Python that I want to run in Mathematica
...
- 451
1
vote
1
answer
162
views
Efficiently collecting results from nested loops
My question involves what is often considered to be horrible Mathematica code; that is, code which is essentially procedural involving nested loops, rather than mapping, threading, and so forth. Here, ...
- 421
1
vote
0
answers
129
views
Import and assign/manipulate the content of a huge number of files efficiently
I have a folder containing eg. around 40K txt files with randomly assigned names.
I am trying to import the content of these files as List/Table and process them ...
- 1,957
3
votes
0
answers
96
views
Return and Function [duplicate]
Can somebody explain the behavior of Return inside a function? I know that Function and If ...
- 60.9k
0
votes
0
answers
73
views
Checking whether a linear homogeneous system with m equations and n>m unknowns, has m unknowns that are sums with positive coefficients of the others
I call a "pseudo-linear", homogeneous system with m equations positively representable, if it has m terms that are sums with positive coefficients of the others. A class with precisely one &...
- 2,380
1
vote
1
answer
127
views
Make a loop while graph is not empty
I'm new to Mathematica and I'm attempting to write an approximation algorithm to compute "maximum" independent sets. What I need to do is given a graph g ...
- 123
1
vote
2
answers
188
views
RecurrenceTable vs For loop : they do not give the same results. Why?
I have a second-order recurrence equation that I want to plot.
I've used two different methods.
The first uses RecurrenceTable, the second uses a traditional ...
- 33
0
votes
1
answer
134
views
How can I transpose SCILAB/MATLAB code with for loop into Mathematica? [closed]
How can I transpose the following SCILAB/MATLAB code into MATHEMATICA?
I took a look at similar questions, but none of them seemed to provide a solution.
...
- 33
4
votes
1
answer
160
views
Efficient way of creating matrices from a very large array while avoiding singular values
I need to create matrix from a large array (>>10000 elements) for further use. I have tried Outer and ParallelTable commands, among which Outer seems to be faster when the array size is not so ...
- 420
1
vote
1
answer
108
views
How do I use Check with Table to skip results that contain error messages
I want to run an iteration where at each step I check whether I obtain an error message, and if I do, I want to not store that result and move on to the next iteration instead. Here's an example of ...
- 403
1
vote
2
answers
125
views
Is this definition similar to a while loop?
Good morning.
Reading some code in a webpage, I found this expression:
X[0] = 0.5; (*edited from x to X*)
X[n_ /; 1 <= n] := X[n] = Sin[n] X[n - 1] + Cos[n]
Is ...
- 45
6
votes
3
answers
342
views
Incrementing a random element of an array repeatedly
Consider this code to simulate a simple instance of the coupon collector problem. We initialize an array to {0, 0} and then keep incrementing a random element until we've incremented every element at ...
- 746
1
vote
0
answers
164
views
Implementation of call/cc or its analog in Mathematica
BACKGROUND
call/cc is commonly used by lisp-like languages as a control flow operator. And mathematica can also be seen as a lisp-like language.
QUESTION
How to complete implement ...
- 111
0
votes
0
answers
91
views
FindMinimum with many Sums and NIntegrates is very slow
I want to calculate the global minimum of an equation which has several hundred Sums (I used 300 in this code), but the calculation is very slow.
My code is as ...
- 101
2
votes
6
answers
659
views
All solutions that satisfy $ x_{1}^{5}+x_{2}^{5}+x_{3}^{5}+x_{4}^{5}-x_{5}^{5}=0 $
I want to find a combination that satisfies all the solutions of the following formula.
$$
x_{1}^{5}+x_{2}^{5}+x_{3}^{5}+x_{4}^{5}-x_{5}^{5}=0
$$
$x_{1}$, $x_{2}$, $x_{3}$, $x_{4}$, and $x_{5}$ are ...
- 776
0
votes
1
answer
213
views
Performance improvements using Table and Compile
I'm converting a code from MatLab to Mathematica. It takes MatLab less than a second to compute it while its more than ten minutes in Mathematica. I was hoping to improve the performance.
Here's a ...
- 590
1
vote
0
answers
59
views
Parallelization with procedural functions, e.g. `AddTo`, `PreIncrement`, and so on
I have a problem that procedural functions don't work with parallelization, e.g. AddTo and PreIncrement. At first, I thought it ...
- 896
0
votes
1
answer
88
views
How make a function NestUntilList that accepts multiple arguments?
Recently the looping construct Until was added to Mathematica in 13.1, based on the ResourceFunction Until created by Jon Mcloone.
I want to make a generalization named NestUntilList.
NestUntilList is ...
- 1,885
0
votes
2
answers
209
views
Real-time function graph display
I would like to see how the graph of the function en[B, i, j, k, p] changes depending on i, j...
- 1,933
0
votes
0
answers
110
views
Do loop Implementation
I want to generalise the following algorithm to a loop overall possible subsets of the original set.
the algorithm has the following form:
ver={X41,X42,X43,X44}
and
...
- 21
2
votes
1
answer
126
views
4
votes
3
answers
446
views
A loop in which three indices are changed
How could this piece of code be written in the Table, or as simply as possible?
...
- 1,933
0
votes
1
answer
151
views
0
votes
1
answer
170
views
Can I use Table or something else instead of While in this case?
I have a very long code that take an extremely large amount of time. I have been using the While loop, but with each iteration, it gets slower and slower, so I know there has to be a better way of ...
- 403
4
votes
2
answers
168
views
How to discard the repeating elements of a list [closed]
Lets say there is a random list of expressions :
a={Sin[x], Sin[3 x], Sin[4 x], Sin[x], Sin[4 x], Sin[x], Sin [5 x], Sin[3 x], Sin[5 x]}
Plot[{a}, {x, 0, 2 Pi}]
...
- 887
2
votes
2
answers
220
views
The way of converting a string to a variable in a loop?
I have 60 txt files which I want to import them into Mathematica using a Do loop. Each file contains some numbers (more precisely, a list of numbers). I want to put ...
- 1,318
2
votes
1
answer
144
views
Jacobian General::ivar issue
I have a differential equation labelled by eq0 and I want to use finite-difference method to solve it. First, I have to set up the system of equations ...
- 787
1
vote
1
answer
419
views
My ParallelDo does not work
I have to do a lot of calculations that take lot of time, and using a Do loop is simply too long. It is the first time I am using ...
- 33
2
votes
0
answers
189
views
The fastest and most scalable way to write a nested loop
The problem is to find the weights {w1,w2,w3,w4} that satisfy the condition. Which is the fastest and most scalable way (e.g. for 10000 weights) to write this ...
- 35
1
vote
2
answers
160
views
Trying to apply numerical method with Do
I am trying the following scheme to learn to implement an iteration using Do loop. I tried to implement the same method using for loop but with same errors. I, therefore, turned to the Do loop to ...
- 19
0
votes
1
answer
93
views
Sorting a list by increasing order algorythm [closed]
Im new to loops on mathematica,was wondering how could I create a function to loop through a list which finds the index of the smallest value of that list, makes a sublist from index 1 to that ...
- 93
3
votes
2
answers
143
views
How to NIntegrate multiple ranges of data at the same time with an output that can be plotted?
I am trying to use the NIntegrate function to find the difference in the area beneath two 2 dimensional splines (how much area of the river bed was lost or gained from one year to the next) but, I ...
2
votes
2
answers
548
views
How can I make 10 variables from a for loop?
I used a for loop to make 4 variables:
For[i = 0, i < 4, i++,bi=0]
But when I write b0 or ...
- 369
-1
votes
1
answer
99
views
0
votes
1
answer
171
views
Length of a For loop [closed]
How to find the length of a For loop?
Here is a simple example:
For[i = 0, i < 4, i++, Print[i]]
0
1
2
3
How to find that there are in total 4 outputs using ...
- 631
6
votes
2
answers
418
views
Perform same operation along dimension of an array
If I want to add the $2\times 2$ matrix b along the first dimension of a that has $n\times 2\times 2$ dimensions I can do this ...
- 593
0
votes
0
answers
77
views
How to "freeze" a parallel program
I wrote a program, parallelized it (using ParallelDo[], SetSharedVariable[] etc.), and enjoyed the wonderful speedup. ...
- 203
2
votes
0
answers
120
views
How to make my own external language cell evaluator
We can type > and select python to insert python external language cell into notebook.
Then we can write python code inside it and evaluate it by pressing ...
- 32.8k
4
votes
1
answer
246
views
Why won't my random walk work in a Mathematica Do loop? [closed]
This produces a nice random walk plot:
...
- 599
3
votes
1
answer
82
views
Keep Reap / Sow results after breaking out of a loop [closed]
I am doing a long calculation where I create a list using Reap and Sow. However, sometimes this calculation gets too wild and I ...
- 51
2
votes
1
answer
294
views
How to create a loop in Mathematica?
Yup, im a newbie, you guessed it. But I have been having fun solving Project Euler problems with Mathematica. I am on problem #8:
The four adjacent digits in the 1000-digit number that have the ...
- 53
4
votes
4
answers
345
views
Quit the loop if encounter error message
First define length-component error (personal term) :
This is an error when we want to get n-th component of a list if n is bigger then the length of the list. For example, ...
- 4,435
2
votes
2
answers
409
views
While loop not working problem [closed]
I am new to Mathematica ,and I am trying to implement this while loop which adds all odd Fibonacci numbers less than or equal to 2 million but it keeps outputting 0 for sum.
Any solutions for that?
...
- 31
2
votes
1
answer
337
views
Why is this Do-Loop taking so much time?
I have this simple Do Loop that, for some reason, takes a really long time for $h<\frac{1}{15}$. Why is this so? Is there a more efficient way in programming such a recursion?
...
- 307