Questions tagged [piecewise]
Questions about the Piecewise function, which is represented by different expressions for different ranges of values of its independent variable.
315
questions
1
vote
1answer
33 views
Interpolation of a “bit by bit” Function
I am facing a problem with integrating a function. I have to integrate the function "bit by bit". This is the smallest working example that shows the problem:
...
0
votes
1answer
54 views
Integrating a function “bit by bit”
I am trying to integrate a function. But for this task I need to do it
"bit by bit". I created a working example that shows the problem.
...
1
vote
2answers
47 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 ...
3
votes
2answers
128 views
Different colours for different sectors of piecewise function
I have some lines of code that generate numerical solutions to equations. Then I want to combine two of these in a piecewise function. The way I did it is the following -lf1[r] and lf4[r] are the ...
6
votes
2answers
140 views
How can I use Callout to label the segments of a piecewise function?
When I plot a Piecewise function, I like to put the function name above each part of the plot. I could not find a way to use ...
1
vote
1answer
83 views
Piecewise function made up of five segments not showing in a plot [closed]
I want to plot 5 parts in a single graph using a piecewise function. But I am not able to plot the last one. Can anyone please help me with it? The code is as follows.
...
0
votes
1answer
112 views
How to solve transient 3D heat equation with robin boundary conditions
Good afternoon!
I'm trying to solve the following heat equation:
with the following boundary conditions and initial value:
Nut I'm getting error while solving it with NDSolve:
...
3
votes
3answers
58 views
Dots at points of discontinuity
So, I got this code:
Plot[Piecewise[{{3, x <= 0}, {x^2 + 1, x > 0}}], {x, -2, 2},
PlotStyle -> {Purple}, Axes -> False, Frame -> True]
and I ...
3
votes
1answer
79 views
Reduce to Piecewise
There are some similar posts on SE, but none of them seems to exactly address my issue.
I need to integrate a rather complicated function (over $x>1$) separately over two domains defined as ...
0
votes
0answers
42 views
Plotting discontinuous functions
I want to plot the two roots of a polynomial function. At some value of the variable x, they "swap" and the lines change. However, I want each branch to have te same line style. Is it possible to ...
3
votes
1answer
107 views
How to set up a Fourier transform?
I am having trouble figuring out how to set up the Fourier transform to:
...
6
votes
2answers
158 views
The correct way of compute indicator function in Mathematica
$$X_1= \mathbb{1}_{[0,1]} $$
$$X_2= \mathbb{1}_{[0,\frac{1}{2}]}, X_3= \mathbb{1}_{[\frac{1}{2},1]}, $$
$$X_4= \mathbb{1}_{[0,\frac{1}{3}]}, X_5= \mathbb{1}_{[\frac{1}{3},\frac{2}{3}]}, X_6= \mathbb{...
1
vote
1answer
41 views
Having trouble when using a piecewise function
I am trying to define a function where H1[x_]= a previously derived value if 0 < x <100 and H1[x_]=x if x>100 so I have used the following piecewise function:
H1[x_]:=Piecewise[{{Evaluate[y[x] /....
0
votes
0answers
20 views
Problem with PiecewiseExpand[Max[ ]]
I have these functions:
By running this command:
FullSimplify[PiecewiseExpand[Max[a, b , c, x, y, z]],
9 <= \[Beta] <= 11]
I obtain:
However I think ...
2
votes
1answer
53 views
Maximization of a a PiecewiseExpand funcion
I have the following 3 piecewise functions and their upper envelope.
...
1
vote
1answer
48 views
Find the intervals where a piecewise is maximum
I have the following 3 piecewise functions and I would like to have the threshold of the upper envelope.
...
7
votes
1answer
109 views
Converting Piecewise function to C code
I'm trying to convert a function to C Code
f = D[Piecewise[{{x^2, -10 < x < 0}, {x, x > 0}}], x]
I decided to scan through conditions and corresponding ...
0
votes
1answer
72 views
Extending periodic piecewise continuous function
I need to plot the piecewise function
$$
f(x) =
\left\{
\begin{array}{r}
x^2, & -2 \leq x \leq 0, \\
0, & 0 < x \leq 1, \\
1 - x, & 1 < x \leq 3. \\
\end{array}
\right.
$$
as a ...
2
votes
0answers
36 views
How to convert output from Reduce into a piecewise function?
Reduce often provides a much fuller solution than Solve. But it's always in the form of a true statement rather than functions ...
2
votes
2answers
70 views
How to define a discrete distribution with non-integer sample space elements (outcomes)?
How to define a discrete distribution with non-integer states (sample space elements)?
I know how to define a discrete distribution with integer states:
...
0
votes
1answer
53 views
Piecewise function [closed]
I have the differential equation
$$
\omega'(t)= \begin{cases}
\frac{1}{J_t}\left(\frac{B}{2}(F_l-F_r)-B_l\omega\right) & \text{if turning=true}\\
0 & \text{if ...
3
votes
1answer
66 views
elegant definition of piecewise linear functions (spline)
As far as I understand, the Spline object is the result of some approximation or interpolation, it is not for directly defining functions.
That's a pity, as that ...
1
vote
1answer
77 views
Piecewise with differential equations
I have the following differential system. The calibration I use is as follows
...
3
votes
1answer
68 views
Piecewise function not evaluating in NDSolve
Perhaps it's something obvious, but why does this simple piecewise function (as well as other conditionals) not evaluate in NDSolve:
...
0
votes
0answers
42 views
Piecewise function to include SawtoothWave function
I am trying to write a Piecewise function that includes the SawtoothWave function. Can someone indicate how to do this, or if it is possible within mathematica?
The piecewise code is here:
...
0
votes
1answer
35 views
How does Mathematica solve this 2D piecewise function from constraints?
I am interested in learning the technique(s) used to solve the following 2D piecewise equation for $x, y$ when given $z$, where $z = f(x, y)$.
$\text{Given that $x \in \mathbb{Z}$, $y \in \mathbb{Z}$}...
2
votes
2answers
40 views
Piecewise function and deriving - solving
I'm working in a (Economics) problem where I want to add two concave (profit) functions in order to maximize them together through one variable (quantity). My problem is that one of the two functions ...
4
votes
2answers
268 views
Why does plot not show where Piecewise function is not zero?
From my user point view this looks like bug. But I am not an expert.
f[x_?NumericQ]:=Piecewise[{{1,x==1},{0,True}}];
Plot[f[x],{x,0,1}]
Does not show ...
1
vote
2answers
49 views
Displaying part of piecewise function
If I define a piecewise function
f[t_] := Piecewise[{{t^2, t < 0}, {Sin[t], t > 0}}]
Which[f[t], t > 0]
how do I display only one part of the function? ...
0
votes
0answers
55 views
Is it possible to unmerge Piecewise expressions?
I have an expression involving Piecewise that I want to break into specific cases. If I let Mathematica's simplification rules loose then it doesn't seem to pick up an obvious cancellation which can ...
1
vote
2answers
41 views
RecurrenceTable of a piecewise recurrence function
How to can I get RecurrenceTable to deal with a piecewise function?
For example,
$
\qquad x_{n+1}= x_n(1.5-0.5x_n)\qquad \text{if $x_n\ge0.5$}\\
\qquad x_{n+1}= ...
0
votes
2answers
32 views
Piecewise vector
I need to have a vector with the length of 15000. The first 4000 elements have value 12, the next 3000 elements, that is 4001 to 7000 be 0 and the rest of it to the last be 5. I have written it with ...
0
votes
1answer
58 views
Returning a string from a piecewise function
I need to define a function that behaves as a piecewise function, but will return a string instead of a value. Part of the function that I have written is provided below. The full function continues ...
4
votes
2answers
205 views
Heat equation with variable conductivity
Let us consider the (very simple) problem
$\qquad \partial_x[k(x)\,\partial_xu]=0,\quad x\in [0,1]$
$\qquad u(0)=0,\ u(1)=1,$ with $l\in(0,1)$
$\qquad k(x)=\left\{\begin{array}{l}k_1^{},x<l\\k_2^...
2
votes
0answers
50 views
Make Mathematica evaluate an integral symbolically
The following integral has a symbolic solution, which MMA does not return.
$\kappa(x) \begin{cases}
\text{mod}(x,1)\le0.5: & 1\\
\text{mod}(x,1)>0.5: & 0
\end{cases}$
$f(z)=\int_0^1 \...
0
votes
2answers
294 views
Fourier series of an arbitrary periodic piecewise function
Let's take a switch function as an example:
$
u(t)=
\begin{cases}
1, & \text{$0<t<dT_s$} \\
0, & \text{$dT_s<t<T_s$}
\end{cases}
$
How can I get Fourier series of it in ...
1
vote
0answers
57 views
2
votes
1answer
94 views
Fast and Listable Piecewise function
I am writing a simulation where I have an array with ten columns and on the order of millions of rows, for which I need to iterate on the order of ten thousand times, making computation time a major ...
4
votes
2answers
68 views
How can I make a NumberLineLogPlot'?
I have a piecewise function that is defined in logarithmic intervals, i.e., the different pieces are defined on
...
0
votes
0answers
45 views
Imposing conditions on argument for a function definition
Suppose that I wish to use "Piecewise" to merge two different interpolating functions (obtained via a NDSolve of some ODE), defined over negative and positive arguments respectively, like:
...
1
vote
1answer
69 views
Integrating piecewise function in two variables
I want to find (and plot) the integral of a 'smooth' version of the Möbius function MoebiusMu[x]:
...
4
votes
4answers
347 views
Continuous non-piecewise equivalent of smoothstep function?
I have a smooth step function given by the piecewise function
...
2
votes
0answers
87 views
Slow Plotting of a Piecewise Function
I have stumbled upon an issue that seems very weird to me. I have two Piecewise functions that describe exactly the same curve. The only difference between them is that the first function has two ...
0
votes
1answer
90 views
Convert a piecewise definition of a single impulse into an impulse train
NOTE: See update at end of question
I have a function smoothstep (based on the derivative of a smoothstep function) that gives a single impulse as follows:
...
0
votes
1answer
183 views
How to change colors of 3D parametric plot
I have a 3D iterative plot, where each iteration (1,2,3) is represented by equation of piecewise linear function. I am trying to change the colors of plot, to get for every iteration (piecewise ...
0
votes
1answer
60 views
Defining a function with a point of finite discontinuity [closed]
I wrote the code for the function $T$ defined on $[0,1]$ by $T(x)=\frac{x+2}{3}$ if $x\neq\frac{1}{2}$ and $T(\frac{1}{2})=1$ as follows.
...
0
votes
2answers
95 views
How to plot 3D discontinuous iterative plot?
I am having troubles with plotting this set of data
triples={{0, 1, 1}, {9/50, 4/5, 1}}, {{9/50, 4/5, 1}, {3/8, 4/5, 1}}, {{3/8, 58333/100000, 1}, {3/4, 16667/100000, 1}}, {{3/4, 0, 1}, {1, 0, ...
0
votes
2answers
82 views
how to get coordinates from a plot of piecewise function?
I am having troubles with finding points from a plot. I have a piecewise linear function given by following inequalities. These inequalities I got from previous calculations where I split two ...
0
votes
0answers
50 views
How to extract envelope for piecewise defined function? [duplicate]
I have a plot generated from an ugly and complex set of piece-wise functions. I'm looking to extract the envelope function from this data set. I've tried a lot of suggestions in other threads, but ...
0
votes
1answer
63 views
Using Piecewise to plot a defined function [closed]
I'm trying to Plot this function:
Between the interval -0.2 < t < 0.1 but it doesn't work. All i get is a blank graph between my intervals. If you could help me out I'd greatly appreciate it.
...
