Questions tagged [arithmetic]
Questions on arithmetic operations in Mathematica.
93
questions
4
votes
1
answer
87
views
Simplify expressions with modulo 2 (Boolean algebra)
Suppose I have a (Boolean algebra) expression
a = p1 x^2 + p2 x (x-1) + 3 p3 + 4 p4 x
where p1, ..., ...
- 179
0
votes
1
answer
53
views
How can I redefine multiplication this way?
I want the product of matrix objects to be evaluated to the matrix object of dot products of the arguments, but only if the matrices commute. Why this does not work?
...
- 3,473
3
votes
1
answer
200
views
How can I redefine multiplication?
For instance, I want 0 Infinity = 0
I tried this: Unprotect[Times];Times[Infinity,0]=0;Times[0,Infinity]=0;Protect[Times];
But ...
- 3,473
13
votes
2
answers
235
views
Arithmetic operations on NumericArrays
Currently, NumericArrays are directly supported by the most important array-related functions, what makes them a very attractive data structure for implementing ...
- 61.3k
1
vote
2
answers
175
views
Express rational and infinite expressions in Mathematica [closed]
I have several doubts about notation. I would appreciate any clarifications.
a) I can express, for example, a periodic or semi-periodic number without writing it in its rational form. Can such ...
- 480
3
votes
0
answers
73
views
Problem with Mathematica Relationship Building
When I enter the following to get Mathematica to open my pod door I get
Could someone try and replicate this? Also, my name is not Dave and I throw my own error...
...
- 7,113
-3
votes
1
answer
106
views
long division acurate answer on dividing long numbers [closed]
ok but first of all if i have the huge number to be divided what will i have to use for the division to be accurate long division or some other formula square root or 2 this is to calculate music ...
1
vote
1
answer
269
views
The square of Abs of a complex number
We all know that
4^2 + 22^2 = 500
Is there a natural way to generates 500 from the complex number ...
- 4,037
0
votes
0
answers
53
views
Ordinal arithmetic
How can I compute with ordinals in mathematica? For instance, I'd like to query $2+\omega > 1 + 2 \omega$.
- 205
5
votes
1
answer
246
views
Does Mathematica simplify calculation when encounter zero?
e.g.
when Mathematica Calculating f[x0]=A[x0] B[x0],
where A[x] & B[x] could be some complicated high dimensional function.
Will Mathematica outcome 0 directly ...
1
vote
0
answers
24
views
Mathematica 12.1: Evaluation result does not show decimals [duplicate]
It surprises me that Mathematica does not show decimals after evaluating the following calculations:
500000+5.05
Result: 500005.
Expecting: 500005.05
...
- 563
2
votes
1
answer
128
views
How does Leafcount work? [closed]
I am curious about how LeafCount works because when I count the number of leaves in my solution to a Wolfram Challenge, I get a much smaller result than those listed on the leaderboard for Multiples ...
- 1,653
2
votes
2
answers
212
views
How to calculate percentage change using Dataset[]
With the following code, I can calculate percentage changes in selected indicators over time. The code is not efficient nor practical to integrate it into Manipulate...
- 5,305
2
votes
3
answers
594
views
Rounding Real number
I have real numbers in array, I want to round (or truncate) these numbers to 2-digit after decimal point, then I want to write values to Excel File
For example if I have
...
- 73
0
votes
2
answers
282
views
How to generate multiplication tables up to nxn?
I'm doing a simple multiplication table and I have this that I'm having a hard time with.
I imagine that there must be a shorter way to do it, what I can't get is that it paints black the first column ...
- 480
7
votes
1
answer
177
views
Running Mathematica in 'SpouseMode'
In this previous question I looked into a deprecated capability of Mathematica from Version 2.
Mathematica command that allows it to read my intentions
Thanks to all for your answers. I note that ...
- 7,113
2
votes
1
answer
81
views
Can we change Mathematica's original number system for arithmetic mod p or other arithmetic systems?
It seems Mathematica has a standard arithmetic system that resembles real numbers. Can we change Mathematica's original number system for arithmetic mod p so that whenever we write expressions, it sum ...
- 5,121
16
votes
3
answers
1k
views
How to enter a repeating decimal in Mathematica
I don't understand how to manipulate numbers with repeating decimal in Wolfram Mathematica language.
For example 0.3... does not work as input and I don't see how ...
- 3,003
3
votes
1
answer
161
views
Solving calculation puzzle [closed]
I recently got asked how to achieve a result of 100 only using the numbers {1,7,7,7,7} (the number 1 can be used only once and ...
- 1,134
1
vote
0
answers
66
views
Explanation on why this gives overflow?
If you have a phrase like $10^{0.00057 \cdot 10^{42}}$ that gives "overflow", what is the reason? Is it because, well, something about the size of this whole thing?
- 115
2
votes
0
answers
67
views
Should I redefine 0^0 [duplicate]
I've found some times, while playing with combinatorics, that Mathematica can't calculate some functions because $0^0$ is not defined as $1$.
(I know that some people think that $0^0$ should be left ...
- 412
3
votes
2
answers
117
views
Can I make RandomInstance use exact arithmetic?
When using RandomInstance on a GeometricScene the answer loses precision when root objects are encountered. Is there a way to ...
- 9,043
2
votes
2
answers
56
views
LocalTime arithmetic
In an attempt to calculate the time difference between two cities I enter:
...
- 1,147
0
votes
0
answers
81
views
Why does Log[Abs[#]] return a complex number?
For a nonzero number $x$, $\log|x|$ should be a real number. Why does the following NestList contain non-real numbers when no numbers involved are close to zero? Is it a bug?
...
- 193
3
votes
3
answers
149
views
Why does the Mathematica give different numerical results?
Why do the two inputs give different values?
in:=(-y)^a /. a -> 2.99 /. y -> -2
out:=7.94474
and
...
- 91
3
votes
2
answers
81
views
Advice for making addition and multiplication tables for my kid
I'm working with my 6 year old on understanding and mastering addition. As a result, I want to be able to make some custom addition (and eventually multiplication) tables for her to fill out.
...
- 679
3
votes
2
answers
252
views
Applying Mod on list of list with outcomes +1, -1, other
I have a list
lis = {{7, 8}, {17, 9}, {11, 10}, {12,10}}
I want to apply Mod to each pair with output +1,-1 or ...
- 2,304
8
votes
3
answers
388
views
Improving Map Function on Lists
Dealing with spectral data (2D lists) where offsets (corresponding 1D list) must be removed from each individual spectrum. Looking for feedback on improvements over my current method.
...
- 560
3
votes
1
answer
111
views
Why Divide does not give the same answer? [closed]
I saw a question on Facebook $8\div2 (2 + 2)=?$
Consider these inputs.
Divide[8, 2 (2 + 2)]
1
$8\div2 (2 + 2)$ using esc+div+esc
16
Why the results are ...
- 10.4k
0
votes
2
answers
142
views
Mathematica doesn't evaluate/simplify arithmetic expression in its output [closed]
I have two matrices, A := {{1, 2, -4}, {2, -2, -2}, {-4, -2, 1}} and ...
- 103
0
votes
1
answer
88
views
Generating columns in table and header for exported data file automatically
I have a code that goes like this:
...
- 303
4
votes
0
answers
80
views
Force computation on IEEE float/double
I'm checking two different procedures that will eventually be used with regular floating point arithmetic. I need to estimate numerical error arising from floating point arithmetic.
Is there a way to ...
- 211
3
votes
1
answer
124
views
Forcing divisions to be a machine-precision floating point divisions instead of multiplication by inverse
I want to imitate machine-precision, de facto IEEE division on Mathematica. On my quick trials I find this surprisingly hard to accomplish, since Mma rewrites a / b ...
- 18.6k
2
votes
1
answer
207
views
How to form subgraphs from a connected graph
I have a connected graph with 72 nodes and its binary adjacency matrix.
I need to find all possible connected subgraphs with exactly 6 nodes, i.e., I need to find all connected subgraphs and each ...
- 565
0
votes
3
answers
75
views
Roots of an algebraic expresion [duplicate]
If in WolframAlpha I put (-8)^(2/3) then it outputs the main root and 3 roots solution too (to the end in a polar graphic).
How can I get the 3 root solution of <...
4
votes
1
answer
401
views
multiply two vectors, component by component [closed]
Would like to take two vectors and multiply components at the same index.For example {a1, a2, a3} x {b1, b2, b3} to produce {a1 b1, a2 b2, a3 b3}.
The following works, but are there some alternatives?...
- 1,027
4
votes
2
answers
110
views
Raise a table of pre-existing data to the power of of one of the variables
NOTE: I have edited this question to give a table whose first elements don't count up from 0 to 5.
I'm using a sample table ...
- 2,121
4
votes
1
answer
148
views
Machine Epsilon is not equal to $MachineEpsilon [duplicate]
I try to wrap my head around machine precision calculations in Mathematica (11.2, Linux). I do not understand the following behavior:
...
- 43
2
votes
1
answer
108
views
How do I emulate Excel's Series AutoFill function?
I have a series of data that I would like to extrapolate out another 20 times. The data in question is:
...
- 123
-1
votes
1
answer
106
views
Could this Be a Bug in V.11.1.1.0 [duplicate]
Here is an elementary third root calculation of -8 (or any negative real number) with and without parentheses, but Mathematica seems to be given different answers!
...
- 423
4
votes
3
answers
193
views
A sudoku-like collection puzzle
I have a puzzle. I'm given a collection of $n$ lists, all of equal (but arbitrary) length $l$. These lists are made up of 0s and a few filled in numbers, like so:
{ {0, 2}, {0,0}, {6, 0}, {0,0} }
...
- 3,604
1
vote
0
answers
50
views
Buggy IntervalUnion with Quantities?
IntervalUnion can give wrong output when used with Quantity:
...
- 15k
2
votes
1
answer
175
views
Two-slot pure function [closed]
I come across this problem in many different forms when doing arithmetic in MMA and have until now just suffered along doing it the long way – having given up trying to figure it out myself – but now ...
- 1,156
1
vote
3
answers
358
views
select, group and manipulate elements in list based on date ranges
Question from a beginner. I have data containing dates and values of the format:
...
- 33
0
votes
1
answer
607
views
How to multiply a vector by a scalar?
I'm plotting a simple 2D graph derived from 4 3D vectors:
...
- 167
4
votes
2
answers
379
views
Interchanging addition and multiplication
Suppose I have an expression that employs addition and multiplication, but no subtraction or division:
$$
2 a + 5 b x^3 + c \;.
$$
I would like to change this to
$$
(2 + a) (5 +b + x +x +x) c \;,
$$
...
- 4,649
9
votes
2
answers
856
views
Why am I seeing what looks like a violation of operator precedence?
Why is it that when I evaluate
2*2.848529281693615`+3*-0.5155083247776808`
I get
(* -2.93688 *)
which is wrong.
...
- 2,517
0
votes
1
answer
204
views
How can I make Mathematica agree that 0^0 = 1? [duplicate]
Occasionally I encounter messages like
Power::indet: Indeterminate expression (0. + 0. I)^0 encountered.
(or just 0^0). I believe I can safely declare these to be 1 for all of my purposes. Is ...
- 1,770
3
votes
1
answer
183
views
Generating prime factorizations from an integer's digits by inserting * and ^ into the digit sequence
Problem
Given a positive integer, output all possible valid prime-factorization "statements" thereof created by inserting zero or more multiplication (*) symbols and zero or more power (^) symbols ...
- 199
11
votes
1
answer
173
views
Trace of -{1} expression
I'm trying to understand Trace. Usually it doesn't repeat but it adds {-1,-1} for his simple expression after having a correct ...
- 619