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Questions tagged [piecewise]

"piecewise" may refer to a piecewise function, a piecewise interpolation or a piecewise regression / smoothing.

Defining a piecewise function normally requires writing if ... else ... clause.

Interpolation is inherently piecewise.

Piecewise regression often refers to piecewise linear regression, or segmented regression.

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How can I make a 3D plot of a piecewise function of two variables?

I am trying to plot the following function in MATLAB: The goal is to stitch all of the different conditions into one graph to make an overall CDF graph. What I have tried so far is the…
James
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Piecewise-Linear Function in Gurobi, understanding the example

I am trying to implement a piecewise-linear objective in a gurobi optimization problem in python. When trying to get familiar with this method using the example from the gurobi web-site (http://examples.gurobi.com/production-scheduling/) I got…
James
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lambdification of sympy piecewise function evaluates every expression

I'm lambdifying a sympy piecewise function trying to do something like this: f = Piecewise((1,(p > -1e-10) & (p < 1e-10)), (1/p, True)) g = lambdify(p,f,"numpy") While >>> f.subs(p,0) 1 I get >>>…
pyrogen
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Using scipy.optimize.curve_fit to fit a piecewise function

I am attempting to write a program that reads two sets data from a .csv file into arrays, and then fits it to a piecewise function. What's most important to me is that these fits are done simultaneously because they have the same parameters. This…
Aaron Rea
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Integrating Piecewise with irrational exponent gives error

When trying to integrate a Piecewise function with irrational exponent, I stumbled upon the following problem: import sympy as sym x, y = sym.symbols(['x', 'y']) pdf = sym.Piecewise((0, x < 1), (x ** -2.5, x < 2), …
Georgy
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Piecewise interpolation for entire data.frame R

I have a dataset from a sources that uses a special compression algorithm. Simply put, new measurements are recorded only when the change in slope (rate of change) is greater than a certain percentage (say 5%). However, for the analysis I'm…
Gautam
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Matplotlib- plot piecewise Linear Function with three parts

I have some data that I want to fit with a piecewise linear function that has three parts. So something like this if there were two inflection points: Unfortunately, when I use the following code, I do not get the correct data, it instead looks…
kb3hts
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Piecewise linear constraint in CPLEX API for MATLAB

I am a (almost) beginner with CPLEX and optimization. I am trying to set up an optimization problem in Matlab using the newly added feature of CPLEX (12.7.1), which enables the definition of piecewise linear (PWL) constraints. However, it is not…
John_3265
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Python - Most efficient way to define a piecewise function

I have a piecewise mathematical function that needs to be evaluated a lot of times, as a subfunction in quad and curve_fit routines. In trying to improve the performance of my program, I found that a lot of time was spent in evaluating conditions in…
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Tensorflow: Can't use tf.case with input argument

I need to create a variable epsilon_n that changes definition (and value) based on the current step. Since I have more than two cases, it seems that I can't use tf.cond . I am trying to use tf.case as follows: import tensorflow as…
D.Badawi
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Curvefitting optimization error when fitting piecewise linear function

I have some data in two arrays, which appears to have a break in it. I want my code to figure out where the break is with using piecewise in scipy. Here is what I have: from scipy import optimize import matplotlib.pyplot as plt import numpy as…
kb3hts
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How do I code a piecewise mixed-model in lme in R?

I followed this example for running a piecewise mixed model using lmer, and it works very well. However, I am having trouble translating the model to lme because I need to deal with heteroscedasticity, and lmer doesn’t have that ability. Code to…
Carina Baskett
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Piecewise list comprehensions in python

What is the easiest/most elegant way to do the following in python: def piecewiseProperty(aList): result = [] valueTrue = 50 valueFalse = 10 for x in aList: if hasProperty(x): result.append(valueTrue) …
user
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MATLAB inline function if statement

I'm trying to define a function as follows: if nn == 0 tau(nn) = 0 else tau(nn) = crazy_function(nn) end However, I want to do it in a single line. I tried tau = @(nn) crazy_function(nn).*(nn~=0) + 0.*(nn==0); But this doesn't work because…
user1936752
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Python: Piecewise function integration error: "TypeError: cannot determine truth value of ..."

This code runs correctly: import sympy as sp def xon (ton, t): return (t-ton)/5 xonInt = sp.integrate (xon(ton, t),t) print xonInt But when the function becomes piecewise, e.g.: import sympy as sp def xon (ton, t): if ton <= t: …
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