Questions tagged [piecewise]
Questions about the Piecewise function, which is represented by different expressions for different ranges of values of its independent variable.
306
questions
2
votes
1answer
46 views
Maximization of a a PiecewiseExpand funcion
I have the following 3 piecewise functions and their upper envelope.
...
1
vote
1answer
45 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
98 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
29 views
Extending a piecewise function defined over a limited domain to be periodic over a larger domain
I need to plot the piecewise function
$
\qquad f(x) = x^2\quad -2 <= x <= 0, \\
\qquad f(x) = 0\qquad 0 <= x <= 1 \\
\qquad f(x) = 1-x\quad 1 <= x <= 3 \\
$
as a periodic ...
0
votes
0answers
33 views
Function inverse to PiecewiseExpand [on hold]
I'm working with very complex piecewise functions which I'd like to decompose into combination of simpler ones. I'm aware of PiecewiseExpand function which does the opposite to what I need. Is there a ...
1
vote
0answers
34 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
55 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
46 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
64 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
63 views
Piecewise with differential equations
I have the following differential system. The calibration I use is as follows
...
3
votes
1answer
65 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
37 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
33 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
38 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
213 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
43 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
53 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
36 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
30 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
55 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
160 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
48 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
175 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
55 views
2
votes
1answer
80 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
64 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
34 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
56 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]:
...
3
votes
4answers
247 views
Continuous non-piecewise equivalent of smoothstep function?
I have a smooth step function given by the piecewise function
...
2
votes
0answers
83 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
82 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
133 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
59 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
77 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
71 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
24 views
Locating the interval on a piecewise function and integration :
I'm recently learning Mathematica to help me compute some difficult stuff, and let's say I have a piecewise-defined real valued function with a finite number of subpieces. I can index the intervals ...
0
votes
0answers
49 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
62 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.
...
2
votes
1answer
40 views
How to read information from a piecewise function?
I defined a periodic piece wise function y[x_] with some discrete steps with Piecewise command and two lists ...
6
votes
2answers
442 views
Solving Stefan's solidification problem - for the case of 3 regions
This question heavily related to this question, where the case of two PDE's are solved along with a zipping condition that is a function of time.
Using the link in the code I have solved this set of ...
2
votes
3answers
501 views
2
votes
2answers
62 views
Combine `EvenQ` and `Clip` to create a series of pulses
I have a function that produces a single impulse spanning the range [-1,1]:
func1 = Cos[Pi*(Clip[x]/2)]^2
I want to create a ...
0
votes
0answers
56 views
Using table and piecewise function together
I am trying to define an equation set, in which the function is very similar to a square wave, but instead, it is defined piecewise at each interval. Now I need to evaluate the equation at each ...
0
votes
0answers
56 views
Unable to Integrate (or NIntegrate) with Piecewise limits
Essentially, I am trying to find the following, either algebraically or numerically, where Z is defined by the piecewise function in the Mathematica code (below):
$\displaystyle{\int_0^{\infty } \...
1
vote
1answer
51 views
Strange behaviour in derivative of Floor function
The function Floor[x] is piecewise constant, hence its derivatives should be piecewise zero.
This is far from true in Mathematica
In[497]:= $Version
Out[497]= "10.1.0 for Microsoft Windows (64-...
1
vote
1answer
53 views
6
votes
2answers
161 views
Switched linear systems
I'm curious whether it is possible to solve switched linear systems within the framework of NDSolve. For example a system of linear ode's like
$$x'(t) = \left\{\...
1
vote
1answer
100 views
How to represent in a 3D graph the set of solutions to this system of inequalities?
I am studying this piecewise function:
...
1
vote
1answer
50 views
Mapping over a piecewise function
This is a followup to a question I posted earlier today. Suppose you have a piecewise function such as "snap=max[x,0]= x if x>0, 0 otherwise".
Then you would think that it must be straightworward to ...
2
votes
3answers
107 views
Identifying maximal element in a list with case distinctions
I need to create code that identifies the positions of all maximum elements of a list. I already know that if myList contains only numbers, I can do
...
