varn
symbolic variable of a polynomial or a rational
Syntax
symb = varn(p) pm = varn(p, varname)
Arguments
 p
matrix of polynomials or of rationals. In Scilab, only univariate polynomials and rationals are supported. In a matrix, all polynomials or rationals have the same symbolic variable name.
 symb, varname
Characters string: current or new name of the symbolic variable. Allowed characters are the same as for variables names (see naming rules).
 pm
matrix of polynomials or of rationals, equal to
p
, with its variable name set tovarname
.
Description
symb=varn(p)
returns in symb
the name of the symbolic variable of polynomials p
.
varn(p,'s')
returns a polynomial matrix with same coefficients
as p
but with 's'
as symbolic variable (change of variable name).
varn([])
yields [].
Examples
With a matrix of polynomials:
> s = poly(0,'s'); p = [s , 1s^2] p = 2 s 1 s > v = varn(p) v = s > typeof(v) ans = string > px = varn(p,'x') px = 2 x 1 x > px == p ans = T T
With a matrix of rationals:
f = %z/(%z1); f = [f f^2] varn(f) fx = varn(f, "x") fx == f
> f = %z/(%z1); f = [f f^2] f = 2 z z   2 1 + z 1  2z + z > varn(f) ans = z > fx = varn(f, "x") fx = 2 x x   2 1 + x 1  2x + x > fx == f ans = T T
See also
 poly — Polynomial definition from given roots or coefficients, or characteristic to a square matrix.
 rlist — Scilab rational fraction function definition
 naming rules — Naming rules for variables and functions
History
Version  Description 
5.5.1  Extension to rationals 
6.0.0 

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