Questions tagged [piecewise]
Questions about the Piecewise function, which is represented by different expressions for different ranges of values of its independent variable.
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How to transform the regions in which a piecewise function are defined?
I have a function f[x,y,z] that has a piecewise definition, i.e., its values depends on the ranges of the arguments. Now suppose I have a coordinate transformation <...
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0
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Improving the curve of a quadratic spline interpolation
I have these data and I want to make a curve using quadratic spline interpolation. I am successful in computing the equations and plotting the curves. However, I noticed that the peaks of the curves ...
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votes
1
answer
34
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Piecewise integration doesn't evaluate
I'm trying to integrate the following function:
$$q(d, \theta) = q_x(d, \theta) + q_y(d, \theta) - 2q_x(d, \theta) q_y(d, \theta)$$
where $q_x(d, \theta) = \min\left(2 - d\cos\theta, d\cos\theta\right)...
0
votes
1
answer
58
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Finding the maximum of a symbolic piecewise function
I have the function:
coded as:
...
4
votes
1
answer
61
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Confusing cases in Piecewise
The following
FullSimplify[Integrate[Exp[I ω t] Sin[ω x]/ω, {ω, 0, ∞},
Assumptions -> t > 0 && x > 0]]
gives a piecewise output of the form
I ...
- 63
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votes
0
answers
22
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Problem with Piecewise function applying to matrix of polynomials
I have a matrix of a polynomial - function f
f[t_, i_] := wielomianSpline[t, tx[[i]], wspfi[[i]]];
and I want to evaluate the ...
2
votes
1
answer
99
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Need an equation for modeling Tytler's Cycle
In all cultures over all time there appears, in different languages for different countries, the maxim "Shirtsleeves to shirtsleeves in three generations." This is a function with three ...
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36
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Issue with piecewise functions and lists of rules
I have a list of data that I am connecting with a simple piecewise function. I then want to evaluate the piecewise function at a different list of points. I can do it the long way, but I am wondering ...
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Solving first-order ODE with piecewise component
I have an ODE I'd like to find an analytical solution to,
$$
\frac{dZ}{dt}=-\alpha Z+\frac{\beta X^n}{(1+X^n)(1+Z^n)} $$
where
$$
X(t) =
\begin{cases}
1 & 1 \leq t \leq 6 \\
...
- 11
6
votes
2
answers
510
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How can I plot this piecewise function? [closed]
How can I plot function $g(x)$ given below:
The following attempt I have tried does not work and returns errors:
...
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3
votes
1
answer
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How is this type of piecewise function represented and calculated? [closed]
How is this type of piecewise function as follows in the picture represented and calculated?
Use:
...
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2
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4
votes
1
answer
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Put a standalone wall barrier inside a 2D square well potential
Here is the code for the 2D square well potential:
v[x_, y_] := Piecewise[{{1, 58 < Abs[x]}, {1, 58 < Abs[y]}}];
Plot3D[v[x, y], {x, -70, 70}, {y, -70, 70}]
Is Piecewise the right function to ...
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0
votes
1
answer
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Using NDSolve on piecewise-defined system of ODEs
I'd like to use NDSolve to solve a system of n coupled 1st-order linear ODEs expressed in matrix-vector form, but which are definied piecewise in n-space (in particular, to represent different linear ...
2
votes
1
answer
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How to plot this two variables piecewise function?
I was wondering if there is a suitable way to plot the function
$$f(x, y) = \begin{cases} x & y < x^3 \\\\ y & y \geq x^3 \end{cases}$$
Maybe with piecewise? But it's a two variables ...
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0
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29
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Issues while using WhenEvent and HeavisideTheta inside NDSolve
What I am doing?
Integrating a piece-wise ODE using NDSolve. The piece-wise part is governed by HeavisideTheta.
Objective?
The goal is to update numerical values when an event is detected. This is ...
0
votes
0
answers
50
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Piecewise Boundary Condition for axisymmetric heat equation [duplicate]
I'm trying to solve the 2D axisymmetric heat equation, where only one section of the tube is being heated up. I have written the following code below:
...
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1
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How can one build this kind of graphics? What kind of plot is it?
i want to know how can i build this kind of plot?
its a graphic of Moment -150 to 150(H.m)in fuction of time from 0 to 6 seconds.
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votes
1
answer
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RuleDelayed (:>) involving Piecewise leads to Piecewise::pairs warning in ReplaceAll (/.)
When I write a replacement rule like this:
Piecewise[{{x^2, x < 0}}] /. Piecewise[a_, b___] :> Piecewise[a, b]
It works fine, but I get the unexpected ...
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1
vote
1
answer
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How to synatx a piecewise where x=0 is undefined?
How to write the synatx for a piecewise where x=0 is undefined in the domain of the function, and according to the below conditions ?
y := Piecewise[{{1, 0 < x < Pi}, {-1, -Pi < x < 0}}]
2
votes
2
answers
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Combining two interpolating functions via Piecewise or If is very slow
For a given set of parameters $(i,l,m)$ I have a function which has been evaluated on a grid $x \in (-2,2)$. Since this function is not smooth (only continuous) at the "interface" $x=0$, I ...
- 1,359
4
votes
1
answer
79
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Piecewise Recursive function with 2 arguments
The following code is not working for argument nn>1. Hold statement Hold[0.62+v0[1,0]] come as output for v0[2,0].
...
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0
answers
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NDSolve not handling discontinuity in initial condition [duplicate]
I am trying to solve a PDE in two variables z and t. This PDE is from "Universality of Capillary Rise" by Zhou and Doi (2020). There is additonally a parameter n that can take positive ...
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Define regular function as difference of two piecewise functions
Consider a piecewise smooth function,
...
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1
answer
60
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0
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0
answers
69
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How to fit piecewise functions with unknown domain?
Thank you for your comments, I will discribe the question in more detail.
I have a piecewise function as below and I'm looking for the parameters :...
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1
vote
1
answer
62
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Piecewise function with form determined by current value
I would like to create a piecewise function that determines the dynamics of a variable $x_t$ as follows:
Given a starting value $x_0$ and a parameter $\hat{x}$:
...
- 407
0
votes
2
answers
165
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Accurate and efficient sampling of interpolated functions
Suppose we are given two interpolated functions
...
- 467
1
vote
1
answer
155
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Creating FormPage Calculator with a Piecewise Function
I am trying to make a calculator to help my mom calculate late fees in our rental property business. Thus, in this calculator all you're supposed to do is input the date on which the tenant is paying ...
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-1
votes
1
answer
115
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Finite Jerk Motion Profile
I try to define a function to plot a motion profile with constant jerk.
It seems that my function doesn't work.
Would you help me to debug my function ?
I guess my issue comes from a bad management of ...
- 1,089
3
votes
2
answers
114
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Plot a sequence of functions in one plot
I would like to plot a sequence of functions in one plot.
My function is defined piecewise:
...
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votes
2
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145
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Defining Piecewise function using an Interval object
I was trying to define a Piecewise function using a previously defined Interval object (that is the union of several intervals). However, I realised that I wasn't ...
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2
answers
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Derivative of piecewise function returns one more case
I define the following piecewise function:
U[c_,n_,g_,p_]:=Piecewise[{{c^(1-g)/(1-g)-n^(1+p)/(1+p),g!=1}, {Log[c]-n^(1+p)/(1+p),g==1}}]
When I take the derivative
<...
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votes
1
answer
126
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How to plot a function with different conditions (if or which or piecewise)
The given function is
This function is plotted to be
...
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7
votes
2
answers
342
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How to remove branches in Piecewise with measure 0
I am doing Convolve over UnitTriangle in 2 dimensions and the resulting piecewise function has conditions with measure zero (...
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1
answer
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I can't plot a certain solution
DSolve[{x''[ u] == -(1/ 2)*(2*1*(\[CapitalTheta] (u + a) - \[CapitalTheta] (u - a)))*x[u]}, {x[u]}, {u}];
x[u] /. {{x[u] ->
C[1] Cos[Sqrt[2] Sqrt[a] u Sqrt[[...
1
vote
2
answers
134
views
NDSolve with piece-wise function and BVP
How to numerically solve a system of differential equation with boundary conditions and piece wise affine functions ?
Consider the following system of differential equations from some optimal control ...
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1
answer
116
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How to plot the derivative of a piecewise discontinuous function (by excluding discontinuity points)?
With the following code I am trying to get a plot for the derivative of the ftot1 function, which is a piecewise discontinuous function defined as the sum of other two piecewise discontinuous ...
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0
answers
66
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Using DSolve, For A System With A Piecewise Function, And For Given Boundary & Continuity Conditions
I'm trying to solve a system of ODE's, analytically, to find the integration constants.
The system is the following (with zUpper=125 000 and zLower= 200 000).
For 0 <= z <= zUpper:
3 T''[z] == 0....
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vote
1
answer
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Derivative of long expression renders Piecewise[…<<…>>…] in Jupyter notebook
My mathematical problem is to solve the optimization problem:
$$ Max_{u} \quad \mathbb{E}[\gamma S-S^2]$$
where $$S= A_0 u X+a-\max(\alpha u X+b,0)$$
with $\gamma,A_0,a,\alpha,b$ some constants and $X\...
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1
vote
1
answer
60
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Vectorplot shows empty result
I've tried to draw a vector plot with piecewise functions, but it shows empty result.
When I don't use piecewise functions, Vectorplot works well..
I can't figure out what the problem is.
I would ...
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0
votes
0
answers
61
views
Numerical integration of iterated integral with piecewise integrand
I need to plot the following integral:
$$
\Omega(t)=\int^{x_1(t)}_0 {4\pi x_i^2\rho(x_i,t=t_s)\int^\infty_04\pi x^2\rho_{reg}(x_i,x,t)dx}dx_i
$$
where
$$
\rho(x_i,t)=
\left\{
\begin{...
1
vote
0
answers
50
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A piecewise inequality not simplified to True [closed]
In = Simplify[-a + Piecewise[{{-b, t > c}}] < 0, {a > 0, b > 0, c > 0}]
Out = Piecewise[{{-b, t > c}}] < a
Why the result is not evaluated to ...
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2
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How do I integrate this piecewise function with Mathematica?
I came across the question of what percent of numbers from 0 to 1 have a logerithm whose floor is even. What I did was I made a piecewise function: ...
3
votes
2
answers
186
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FunctionPeriod for functions defined in a Piecewise manner
To create a minimal example, consider a piecewise function:
...
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7
votes
1
answer
167
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Plot discontinuities use Piecewise
how can I get a plot like this?
I tried with in Mathematica 13.0:
...
3
votes
1
answer
68
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Piecewise Functions from List of Functions
I have multiple functions from two different NDSolves that I would piece together. Here is a working minimal example:
...
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1
answer
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5
votes
1
answer
178
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How can I remove the outermost pair of brackets enclosing a Piecewise function when it occurs in an equation?
Recently I have been annoyed by an automatic formatting in MMA, that is when a Piecewise function occurs in an equation, it will be enclosed by a pair of brackets automatically by MMA, although when ...
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2
votes
2
answers
78
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Piecewise based on the length of the list
I want to create a piecewise function that depends on the length of the list.
Let's say I have a list, and a corresponding piecewise function:
...
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