Questions tagged [nonlinear-equation]
79 questions
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vote
2 answers
solve non linear system of equations in sympy
I get a not-expected solution of this 6 equations' non linear system.
I have 6 equations, 6 variables and other 5 constants (symbolic).
import sympy as…
Filippo Forlani
- 21
- 3
1
vote
0 answers
BBsolve for non-linear equation solving does not print results
I have the issue with the function BBsolve and dfsane, that I have a successful convergence, but I don't get the results (par is not printed, only: successful convergence), when trying to solve the following nonlinear equation system.
Any help would…
Wengritzky
- 11
- 1
1
vote
2 answers
R nleqslv difficulties - solving for pH in an acid-base buffer
Goal
Build a theoretical titration curve for the phosphoric acid buffer (1M).
I provide a fully reproducible and self-contained example (of my failures ^.^).
Model equations
Acid-base equilibrium equations for phosphoric acid are:
Model…
Naiky
- 83
- 6
1
vote
0 answers
How it is possible to linearize this equation and to implement it in FreeFEM++ code?
I am contacting you to try to get some answers about a problem related to a non linear problem.
In fact, I tried to linearize the equation so for this I took c1 = c10 + dc1 where c1 is my variable, c10 is an initial constant and dc1 is the…
Lisa.
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1
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1 answer
How should I use syms with solve command in MATLAB?
I am having trouble solving this set of simultaneous nonlinear equations to determine the unknown variables a,b,c,d,e.
It seems like my code enters in an infinite loop and never stops.
syms a b c d…
GAGANDEEP KAUR
- 21
- 2
1
vote
1 answer
How to write a subroutine for initial condition in Nonlinear Schrodinger Equation that depends on x
I am solving Nonlinear Schrodinger equation by split-step Fourier method:
i df/dz+1/2* d^2f/dX^2+|f|^2*f=0
using an initial condition:
f=q*exp(-(X/X0)^24).
But I have to use the condition that q=1 for |x|<1, otherwise, q=0.
So I write the following…
Miracles
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1
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0 answers
Can't seem to get NLsolve to converge in Julia. Can you suggest any tips?
I'm trying to solve a life cycle problem in economics using Julia but I'm having trouble with NLsolve. The model boils down to trying to solve two a two equation system to find optimal leisure hours and capital stock each working period. The…
mark
- 133
- 3
0
votes
1 answer
Solving a symbolic system of equations returns only 2 accurate values
I have to solve a system of equations that satisfice some conditions. When I do it with solve from Sympy, I only get 2 out 8 values correct.
Here's my code.
import numpy as np
from sympy import symbols, exp, Eq, solve
gamma0, gamma1, gamma2,…
Ectobius Rex
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- 1
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0 answers
How to define transfer variables when solving equations in 1stOpt?
I am trying to solve a non-linear integration equations in 1stOpt. The parameters to be solved are x1, y1, Uratio, and 5 transfer variables are used to build the equations: Left, Right, C, pl, pr.
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Problems
1 The code…
0
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2 answers
Solving an equation with one variable in Python
I am trying to solve the equation: log(1+x)/x - 1/(1+x) == 2/3 * q * x**2 for x with q = 4e-4
I tried
import numpy as np
import scipy.optimize as so
q = 4e-4
eqn = lambda x: np.log(1+x) / x - 1 / (1+x) - 2/3 * q * x**2
sol =…
Matrix23
- 103
- 4
0
votes
0 answers
Solving non-linear equation with number of equations greater than number of unknown parameters in R
I am trying to solve the attached equation using R.
I tried nleqslv but it failed do to unequal length of equations and number of parameters.
myFun<- function(p) {
y <- numeric(7)
y[1] = sum(gamma[,1]*x2)/p[1]-sum(gamma[,1]*x1)/(1-p[1]) -…
Ali
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- 3
0
votes
2 answers
Size-1 array error when trying to solve system of nonlinear equations
Here is my code:
import numpy as np
import matplotlib.pyplot as plt
g = plt.figure(1, figsize=(5,5))
delta = 0.025
x1,x2 = np.meshgrid(np.arange(-4,4.1,delta),np.arange(-4,4.1,delta))
f1 = math.sin(x1 + 1.5) - x2 - 2.9
f2 = math.cos(x2 - 2) +…
Nikhil Roka
- 37
- 9
0
votes
2 answers
Three variables exponential equations in Python - solver options
Asking here is my last resort, I do not know where else to look or what my next option would be, apart from changing languages.
I have a set of 3 heavy exponential equations, with 3 variables. All have the unknown variable in the exponent as well as…
nparadina
- 11
0
votes
1 answer
Implementing Newton-Raphson Method for Nonlinear Circuit Simulation with Diode Components
I am working on a circuit simulator based on Modified Nodal Analysis (MNA), aiming to support nonlinear components such as diodes. To solve the nonlinear equations, I have implemented the Newton-Raphson method. However, I am facing issues with my…
Abdo21
- 498
- 4
- 14
0
votes
0 answers
Solving a symbolic system of equations using sympy returns a non-empty result when not including some variables to solve for
I have the following script where I am trying to solve a system of equations symbolically using sympy:
import sympy as sp
from sympy import Eq, Function, Symbol, symbols, solve, simplify, collect, pprint
from sympy import Sum, latex
## TODO Create…
