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Questions tagged [nonlinear-equation]

79 questions
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Applying displacement control loading using Lagrange multipliers in the material non-linear finite element method

Hi I am trying to implement a simple plasticity based finite element code. I am not clear how to set up displacement control applied through Lagrange multipliers. In case of a linear problem, I did the following to apply displcament control and it…
Bruce Lee Jun Fan
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R: Solving for a variable (using the uniroot function)

I am rather new to R and really could need the help of the community with the following problem. I am trying to solve for the variable r in the following equation: (EPS2 + r*DPS1-EPS1)/r^2)-PRC. Here is my (unsuccessful) attempt on solving the…
Jessica168
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Non-linear system of 3 equations with 3 unknowns - Python

I'm doing a project of Off-Shore Wind Energy where I am designing a turbine. This includes to define some of the features of the turbine. I need to solve a system of 3 non linear equations with 3 variables. 3 equations to solve The 3 variables…
Oscar Larrabure
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Why sympy.solve doen't work with these 12 variables nonlinear equation system?

I am trying to solve a 12 nonlinear equation system with SymPy. import sympy q0, q1, q2, q3, q4, q5, q6, q7, q8, q9, q10, q11 = symbols('q0, q1, q2, q3, q4, q5, q6, q7, q8, q9, q10, q11') unitary_energy_condition = q0**2 + q1**2 + q2**2 + q3**2 +…
Damian Valdés Santiago
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Solving a non-linear equation in python

from sympy import Eq, Symbol, solve v = Symbol('v') eqn = Eq(0.55**1.3*((3.91/v)-0.01162)*(0.02472*(v-5)+1.132), 0.0) x = solve(eqn) print(x) real_x = [val for val in x if val > 0] print(real_x) NotImplementedError: Unanticipated argument of Eq…
Ashok Silwal
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Solve a nonlinear equation using ODE45 function in matlab for different values of initial conditions

I have written a script to compute and solve a simple inverted pendalum system.Now suppose that I want to solve the nonlinear dynamic equation of the system with ODE45 function with different values of initial conditions.How could I use a for loop…
MMd.NrC
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Non linear system of equations in matrix form - Python

I am dealing with a non linear system of equations in matrix form in python, namely: F=Af+b(F) Where F is my uknown vector 9x1, A is a known 9x9 matrix, f is a known 9x1 vector and b(F) is a 9x1 vector which is non linear function of the components…
Donald Zeka
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How to solve s system of coupled nonlinear ODES already given the state vector

I have a nonlinear dynamical system. I have found the equations of motion, which results in the following state vector: The variables I used are I keep getting all kinds of errors. What am I doing wrong. Thank you! function f = fun_1(t,x) m0 =…
Missael
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How to implement your own nonlinear function in nlmer in R?

I am trying to implement a new nonlinear function to use in nlmer function in lme4 package. But I'm not sure what the problem is. This is the first time I'm trying to use nlmer but I'm following all the instructions I've found on the internet. The…
Oğuz Salih Okçu
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How can I plot frequency response for a vibratory system with nonlinear differential equations?

I have a system of nonlinear differential equations for a 3 degree of freedom vibratory system. system of differential equations First I want to plot y, y_L and y_R against time (for a given value for Omega) and then I want to plot the domains (max…
Yousef Ahmadi
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How to get all roots (complex and real) from a complex non-linear system using python?

I am trying to solve a complex non-linear system. The problem is that there are many roots, and some of them are complex roots. From these roots I need to select only the one that the real part is between [0,1] and does not have complex part (ex:…
João Pereira
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How can I solve non linear equation in R and uniroot function

How can i find the value of x using R for the equation a(x^b)+k*log(1+(x^c))+log(1-(u^(1/d)))=0 for the values u=0.1,c=0.8,k=1.2,d=1.5,a=0.9,b=1 They got the ans as 0.0539. But i didn't get this ans.
Akhilraj N S
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SciPy root gives a ValueError depending on method

I am using SciPy root function to find a root of a function which involves an ODE (in the function passed to root I am calling SciPy solve_ivp). When using "krylov" method in the root, it solves it with no problem. But when I use any other method…
Kourosh
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Extracting coefficients of non-linear equation across categorical variable

This question appears to be off-topic because it focuses on programming, debugging, or performing routine operations, or it asks about obtaining datasets. You could try the support links we maintain or the Open Data site instead. If you are asking…
Daniel Fishburn
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Solve a linear equation which has 16 variables

I'm trying to solve a 16 variable linear equation. I tried in Matlab but it says that the solution could not be found. Is there an efficient way to solve the equations. The equations are a = a^2+e^2+i^2+m^2, b = a*b+e*f+I*j+m*n, c =…
Monica
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