Substitutions for powers with new symbolic variables

xyli · October 31, 2022, 5:08am

Does anyone know if there are other Julia functions that can substitute “x*y” by “a”? I had a discussion with Symbolics developers about it, but it seems to be a deadlock now. Please kindly see the discussion here,

github.com/JuliaSymbolics/Symbolics.jl

substitutions for powers with new symbolic variables using Symbolics.jl

opened 09:29PM - 29 Oct 22 UTC

xiang-yu

I have a vector "g" with high order polynomial elements x^alpha. I want to repla…ce the high order polynomials x^alpha with first order variables "phi". Here is my Julia code using Symbolics.jl, phi = Symbolics.variables(:phi, 1:3) g = Symbolics.variables(:g, 1:3) g[1] = a * x^2 + b * y^2 + d * x*y + 1 g[2] = b * x^2 + a * y^2 + d * x*y + 1 g[3] = 0 m = Symbolics.variables(:m, 1:3) m[1] = x^2 m[2] = y^2 m[3] = xy expr = Symbolics.variables(:x, 1:3) for i = 1:3 expr[i] = substitute(g[i], Dict(m[i]=>phi[i])) end This returns, julia> expr 3-element Vector{Num}: g₁ g₂ g₃ This is not right because it should be a*phi1 + b*phi2 + d *phi3 +1 b*phi1 + a*phi2 + d *phi3+1 0

Topic		Replies	Views
Substitution of products of symbolic variables Modelling & Simulations symbolic , symbolics	3	460	October 17, 2022
Substitute powers and powers of fractions General Usage symbolics , symbolic-utils	4	446	June 22, 2022
How to simplify a symbolic expression General Usage question , symbolics	11	1524	November 22, 2024
Substitution and simplification of terms that do not appear explicitly, using `Symbolics.jl` (and `SymbolicUtils.jl`) New to Julia symbolics , symbolic-utils	6	615	March 23, 2023
Symbolics.jl substitute limitations General Usage symbolics	11	1139	July 23, 2021

Substitutions for powers with new symbolic variables

Related topics