How can I control the tolerance in vpasolve?
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I am using vpasolve to solve a system of seven equations in seven unknowns.
I have a set of data that solve the system with a tolerance of 0.1e-3 (that is, the tolerance with which the absolute value of the difference between the left-hand side and the right-hand side of each equation is equal to zero). Such a tollerance is OK for my applications, but, unfortunately, vpasolve uses as default tolerance a tighter value and it is not able to find the solutions of my system.
How can I control the tolerance in vpasolve?
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Answers (1)
Sulaymon Eshkabilov
on 14 Dec 2023
Here is one example show how to adjust vpasolve tolerance:
syms x
EQN = sin(2*x) == 0.5;
% Default
sol_D= vpasolve(EQN,x)
% Controlled using digits()
N = 3;
digits(N)
sol_C= vpasolve(EQN,x)
2 Comments
Dyuman Joshi
on 14 Dec 2023
This just changes the number of significant digits of the output. It does not satisfy the tolerance, see below.
And I don't think vpasolve() uses any tolerance to solve.
syms x
EQN = sin(2*x) == 0.5;
% Default
sol_D= vpasolve(EQN,x);
% Controlled using digits()
N = 3;
digits(N)
sol_C= vpasolve(EQN,x)
isAlways(abs(0.5-sol_C)<10^-N)
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