poly

Arguments

a

a matrix or real number

vname

a string, the symbolic variable name. The string must be 4 characters max.

"flag"

string ("roots", "coeff"), default value is "roots".

Shortcuts can be also used: "r" for "roots" and "c" for "coeff".

Description

If a is a matrix,

p is the characteristic polynomial i.e. determinant(x*eye()-a), x being the symbolic variable.

If v is a vector,

• poly(v,"x",["roots"]) is the polynomial with roots the entries of v and "x" as formal variable. (In this case, roots and poly are inverse functions).

  Note that Infinite roots gives zero highest degree coefficients.

• poly(v,"x","coeff") creates the polynomial with symbol "x" and with coefficients the entries of v (v(1) is the constant term of the polynomial). (Here poly and coeff are inverse functions).

s=poly(0,"s") is the seed for defining polynomials with symbol "s".

Examples

s=poly(0,"s");
p=1+s+2*s^2
A=rand(2,2);
poly(A,"x")
//rational fractions
h=(1+2*%s)/poly(1:4,'s','coeff')

See also

• coeff — coefficients of matrix polynomial
• roots — roots of polynomials
• varn — symbolic variable of a polynomial or a rational
• horner — polynomial/rational evaluation
• derivat — Rational matrix derivative
• matrices — Scilab objects, matrices in Scilab
• rational — Scilab objects, rational in Scilab

History