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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2
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1answer
46 views

Maximization of a a PiecewiseExpand funcion

I have the following 3 piecewise functions and their upper envelope. ...
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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
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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
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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 ...
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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
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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
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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
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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
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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
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1answer
63 views

Piecewise with differential equations

I have the following differential system. The calibration I use is as follows ...
3
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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: ...
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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
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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
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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
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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
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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? ...
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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
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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
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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
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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
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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
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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 \...
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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 ...
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0answers
55 views

Piecewise function inside Integrate - Wrong result

I tried to evaluate the following integral: ...
2
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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
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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 ...
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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
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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
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4answers
247 views

Continuous non-piecewise equivalent of smoothstep function?

I have a smooth step function given by the piecewise function ...
2
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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
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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
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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
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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. ...
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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
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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
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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
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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
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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
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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
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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
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3answers
501 views

Solve piecewise function

I have two piecewise function ...
2
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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
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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
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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
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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
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1answer
53 views

Help For Solving Complicated Function

I have a piece-wise defined function: ...
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
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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 ...