Solve Nonlinear System of Equations

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SUMMARY

The discussion focuses on solving a nonlinear system of equations involving vectors {C, R1, R2, R3} and known vectors {S1, S2, S3} using Python's SciPy library. The user attempted to utilize scipy.fsolve but encountered issues due to an insufficient number of independent equations relative to the number of variables. The equations include constraints such as CTR1=S1, CTR2=S2, CTR3=S3, and orthogonality conditions among the vectors R1, R2, and R3. The user seeks guidance on over-constraining the problem or finding additional constraints to solve the system effectively.

PREREQUISITES
  • Understanding of nonlinear systems of equations
  • Familiarity with Python and the SciPy library, specifically scipy.fsolve
  • Knowledge of vector mathematics, particularly orthogonality and normalization
  • Basic experience with MATLAB or Python for numerical computations
NEXT STEPS
  • Research methods for over-constraining nonlinear systems of equations
  • Learn about alternative solvers in SciPy, such as scipy.optimize.least_squares
  • Explore MATLAB routines for solving nonlinear equations, particularly fsolve
  • Investigate techniques for generating additional constraints in vector systems
USEFUL FOR

This discussion is beneficial for mathematicians, data scientists, and engineers working with nonlinear systems, particularly those utilizing Python's SciPy library or MATLAB for numerical solutions.

phil0stine
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Hi, I have a set of vectors that I would like to solve for in a nonlinear system of equations.

I have tried to use scipy.fsolve to solve the system, but without success. I believe the problem is that scipy expects the same number of inputs as outputs. I have a 12x1 input vector, but I can only generate 9 independent equations.

I would appreciate any help with this, for example how I could over-constrain the problem, or am I missing something?

The vectors {C,R1,R2,R3} are all (3x1). There are also a set of (3x1) vectors {S1,S2,S3} that are known.

The equations are as follows:

CTR1=S1 (1)

CTR2=S2 (2)

CTR3=S3 (3)

and finally

[R1 R2 R3]T[R1 R2 R3]=I

which can be reduced to

R1TR1=R2TR2=R3TR3=1 (4,5,6)

R1TR2=R2TR3=R3TR1=0 (7,8,9)

R2TR1=R3TR2=R1TR3=0 Would give me 12 equations, but they are exactly the same as Equations 7,8,9.

So I don't know how to proceed. I would appreciate if anybody could point me in a direction, or to a matlab/scipy routine.
 
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I think I have it, I cannot solve the system without an additional set of constraints.
 

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