Questions tagged [conditional]

Questions about programming or mathematical constructs that enable verification, selection, or branching behavior when one or more criteria are determined to be True.

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3
votes
3answers
68 views

count conditional items in list

I have a list of the form: {1,1, (1 if x>y, -1 if y>=x), -1} I want to count the number of 1's in the list. The output I'm looking for is something of the ...
0
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0answers
18 views

Optimization of storages capacity

Consider a series of storages where different goods are added into daily. I would like to optimize the distribution of these goods between the storages in a way which takes into account some ...
0
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0answers
39 views

Integrals with conditional result

I am trying to get Mathematica to evaluate integrals such as the well-known Fourier orthogonality relations $\int_0^L \sin \frac{2 m \pi x}{L} \sin\frac{2 n \pi x}{L}\,\mathrm{d}x=\begin{cases}0& ...
3
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2answers
104 views

How to keep Switch default case as original function?

For example of below Switch function. In[]:= Module[{f}, f[x_] := Switch[x, 1, 2, 3, 4]; {f[1], f[3], f[x]} ] Out[]= {2, 4, Switch[x, 1, 2, 3, 4]} ...
0
votes
1answer
46 views

conditional statement in function

It seems the equality condition does not work as expected. ...
2
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2answers
43 views

Vanishing function and Manipulate

Within Manipulate, I want to vanish certain controls if other controls satisfy a specific condition. The simplest case is to consider two checkboxes, ...
0
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1answer
47 views

Is using an If[] condition faster than KronckerDelta[]?

I have a code which has a term in a summation like: KroneckerDelta[M,0]*func[M] where func[M] is a time consuming numerical ...
1
vote
1answer
44 views

Plot when multiple conditions are satified [closed]

I have a code which goes like this: ...
0
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0answers
11 views

Min of a set defined with conditions

I would like to define this parameter inside a function: $R = \min\left\lbrace i \in \left\lbrace 1,\cdots,n \right\rbrace \; : \; ((p+i)\mod n) \; \neq a_{j} \; \forall j \in \left\lbrace 1,\cdots,m ...
2
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3answers
102 views

Specifying condition with NIntegrate

I have an integral $$ P_{\frac12 + \mathrm i\mu}(\eta) = \frac{\sqrt{2}}{\pi} \cosh(\pi\mu) \int_{0}^{\infty} \frac{\cos(\mu\tau)}{\sqrt{\cosh\tau + \eta}} \mathrm d\tau, \quad \eta \geq 1, \quad \mu ...
4
votes
1answer
121 views

Why does D ignore conditions specified on a custom function?

I define a function with a condition like so. ClearAll[foo]; foo[expr_] /; FreeQ[expr, bar] := expr Such that foo[12] returns ...
5
votes
3answers
133 views

Among the first 10,000 multiples of 17

Hello I'm new with Mathematica and I can't find a way where I can do this condition. Among the first 10,000 multiples of 17 how many have the sum of their digit multiple of 17? The part for the ...
1
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0answers
29 views

Are the conditions in ConditionalExpression necessary or sufficient?

I computed a limit and obtained it in the form of a ConditionalExpression (see below). Substituting the variables with numerical values in the resulting formula ...
1
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0answers
51 views

What does a single vertical bar mean in ConditionalExpression? [closed]

I got the condition below as part of a ConditionalExpression. Those single vertical bars before and after $\frac{1}{k1}$ appear to be an absolute value but I don't ...
0
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0answers
44 views

Using If statement to evaluate lists

I have a list of x,y values and i am finding the distance between each point, So for 20 point in my file I have something like this, ...
1
vote
1answer
38 views

Defining a conditional statement for a function

I am trying to define a function that is zero when it is evaluated on real numbers and on a preset list of symbols. I am doing this by using ...
4
votes
1answer
77 views

Use Lookup on associations that contain conditional statements

I am using conditional statements in a list of rules to replace values in a vector of data. Since the same operation can be performed faster using Lookup on associations I would like to use this ...
1
vote
1answer
62 views

Multiple conditions in If function

I wrote a function which returns 1 if x^2 + y^2<=1: f[x_, y_] := If[x^2 + y^2 <= 1, 1] Now I'm trying to continue this function to take in multiple ...
5
votes
4answers
293 views

Recursive function, if and which statements

I am given this question: Let a function $ T_n(x) $ be defined by: $$ T_{n+1}(x) = \frac{1}{x} T_{n-1}(x) - \frac{2}{7} T_n(x), $$ where $ T_0(x) = 1, T_1(x) = x $. I need to construct a recursive ...
1
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1answer
43 views
1
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2answers
106 views

Automate table to display figures

With reference to the post Automate Poisson Football Scores Prediction, I succeded in defining the Poisson probability density function for home (μh=A) and away (<...
1
vote
1answer
32 views

How to use conditional clause inside NDSolve

I am trying to solve a differential equation that changes its behaviour depending on the value of the dependent variable. I've tried as shown below, but the computer does not understand my If clause ...
0
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0answers
53 views
3
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2answers
89 views

How does mathematica decide what `x_` is in `MemberQ[list,x_/;(x==#)]&/@list`

Consider the following code: list={1,2} MemberQ[list, x_ /; (x == #)] & /@ list This gives {True,True} ...
0
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0answers
22 views

Using a Which statement with Graphics3D [duplicate]

*Problem solved in the comments I am trying to write a function that outputs a different graphic depending on the user's input, with four total options. I was making a test version and am running ...
3
votes
3answers
123 views

Is there a way to speed up the following calculation Table[If[TrueQ[],k,Nothing],{k,10^5,10^7}]

I've the following code: Table[If[TrueQ[2+3^k>2^k+(-1+2^k)*Floor[(3/2)^k]],k,Nothing],{k,10^5,10^7}] Is there a way to speed the calculation up in Mathematica ...
1
vote
1answer
39 views

Aligning Conditional Controls in Manipulate

Consider the following code ...
13
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0answers
107 views

Reduce[Sin[x]==0,x] splitting odd and even multiples of Pi

as from Title, I'm wondering why Mathematica does not automatically give a single, simple solution for the problem Reduce[Sin[x] == 0, x] for which I obtain the ...
5
votes
2answers
661 views

How to optimize the following function?

Consider the following function: function[x_, y_] = If[x < Exp[y], Sqrt[1 - x/Exp[y]], 0]; functionTotal1[x_] = Sum[function[x, 0.02*j], {j, 0, 4*10^5, 1}]; ...
1
vote
1answer
59 views

Identifying transitions in an array

I have two arrays of elements. The second array is generated by the transfer of one or more element to another position. I want to know which element is transferred to which position. Following is the ...
7
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2answers
221 views

Randomly generated coordinates

I want to code that will do the following: Write a Mathematica function called randomHop that takes as its argument a list containing two coordinates x and y; ...
1
vote
2answers
50 views

How to choose model parameters using `Piecewise` function

The following code (developed by m_goldberg) works as expected. The model parameters can be selected by using Button, being ...
0
votes
1answer
43 views

Conditionally returning a constant if function returns Undefined

Often times functions might return Undefined in Mathematica, e.g. when the Volume@RegionIntersection is called for 2 objects ...
5
votes
3answers
325 views

How to kick out points that are specific to a function

I have a list of xi,yi points. I want to remove any points from the list where x^2+y^2<1. I probably have to write a for loop of some sorts, not sure how to begin. ...
3
votes
1answer
29 views

Condition in SparseArray does not check the condition for some matrix elements

Consider the following MWE: SparseArray[{{i_, j_} /; (IntegerDigits[i - 1, 2, 2][[1]] == 0) :> 1}, {4, 4}] This should give a $4\times 4$ matrix in which the ...
3
votes
1answer
40 views

Changing ContourStyle based on an inequality

I would like to create a bifurcation diagram with ContourPlot. Suppose I want to plot the contour 1-2*a*Q+3*Q^3==0 with ...
2
votes
1answer
104 views

Conditional expectation

Suppose I have a bivariate normal random vector $(Y,Z)'$ where $Y\sim N(μ1,\sigma_1^2)$, $Z\sim N(μ2,\sigma_2^2)$, and $Cov[Y,Z]=\sigma_{12}$. If I want Mathematica to compute the conditional ...
1
vote
1answer
43 views

How do I get my function to output only true case for conditions on its arguments

I am quite new to Mathematica and have an issue regarding which statement. cut[x_, y_] := which[x>y, doFunctionX[], y>x, doFunctionY[]] cut/@{X,Y}] I wish ...
0
votes
3answers
71 views

How to find the root of g[x_] using If?

How can get roots only saved in the list? Input g[x_] := x^2 + x - 6; g /@ Table[i, {i, -10, 10}] If[g[x] == 0, i, Nothing] Output {-3,2} How can I achieved ...
0
votes
0answers
35 views

Mathematica Function Taxicab Numbers [duplicate]

I have spent days trying to compile this code and I cannot generate a list of taxicab numbers for the Hardy-Ramanujan Theory. Here is the module I wrote earlier: ...
4
votes
1answer
126 views

How to include conditional statements in NIntegrate?

I have a function g which is the result of another integrated function f. This function (f) ...
0
votes
1answer
54 views

Getting unexpected results form If expressions [closed]

I'm mystified by this: g[a_, b_, c_] := Module[{d}, d = If[(b < 1), b, b + 1]; If[a < b, d = 0.]; d*c] g[a, 20, 40] ...
2
votes
0answers
100 views

Is Mathematica computing the conditional expectation correctly?

Given a simple case of say 2 independent trials each with probability of success 1/3. Consider a random variable that is gives the 3 times the total successes. We can define this random variable in ...
3
votes
1answer
54 views

Conditional formatting of `Table` with `Join` and `Transpose`

A simple example of what I'm trying to do (but I want to be able to apply the same principle to much larger data sets and with more complicated functions for low ...
1
vote
2answers
82 views
1
vote
1answer
38 views

Checking if an edge is an element of a list of edges

I have graph whose edge list is given by ...
1
vote
2answers
47 views

How do I modify my code to detect cycles in this Collatz-like recursion?

A popular variant of the Collatz recursion is the following. Given a positive integer $n_i$, If $n_i$ is even, $n_{i+1}=n/2$, If $n_i$ is odd, $n_{n+1}=3n-1$. The Mathematica code I'm using to ...
1
vote
3answers
47 views

Highlight largest value in each column of `Table // TableForm`

I am exploring colossally abundant numbers; in particular the set of specific 'critical epsilon values'. I table the function DivisorSigma[1, n]/n^(1 + \[Epsilon]) ...
5
votes
4answers
532 views

List, map function based on a condition

I have the following list: ...
3
votes
1answer
60 views

Combining `With`, `If` and SetDelayed

I just noticed that With[{x = 1}, If[x == 0, 0, 1]] returns 1 (as I expected) but ...

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