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degreevec

Exponents of the leading term of a polynomial

Use only in the MuPAD Notebook Interface.

This functionality does not run in MATLAB.

Syntax

degreevec(p, <order>)
degreevec(f, <vars>, <order>)

Description

degreevec(p) returns a list with the exponents of the leading term of the polynomial p.

For a polynomial in the variables x1, x2, …, xn with the leading term x1e1x2e2 … xnen, the exponent vector [e1, e2, …, en] is returned.

degreevec returns a list of zeroes for the zero polynomial.

If the first argument f is not element of a polynomial domain, then degreevec converts the expression internally to a polynomial of type DOM_POLY via poly(f). If a list of indeterminates is specified, the polynomial poly(f, vars) is considered. FAIL is returned if f cannot be converted to a polynomial.

Examples

Example 1

The leading term of the following polynomial expression (with respect to the main variable x) is x4:

degreevec(x^4 + x^2*y^3 + 2, [x, y])

With the main variable y, the leading term is x2y3:

degreevec(x^4 + x^2*y^3 + 2, [y, x])

For polynomials of type DOM_POLY, the indeterminates are an integral part of the data type:

degreevec(poly(x^4 + x^2*y^3 + 2, [x, y])),
degreevec(poly(x^4 + x^2*y^3 + 2, [y, x]))

Example 2

For a univariate polynomial, the standard term orderings regard the same term as "leading":

degreevec(poly(x^2*z + x*z^3 + 1, [x]), LexOrder), 
degreevec(poly(x^2*z + x*z^3 + 1, [x]), DegreeOrder),
degreevec(poly(x^2*z + x*z^3 + 1, [x]), DegInvLexOrder)

In the multivariate case, different polynomial orderings may yield different leading exponent vectors:

degreevec(poly(x^2*z + x*z^3 + 1, [x, z])),
degreevec(poly(x^2*z + x*z^3 + 1, [x, z]), DegreeOrder)

degreevec(x^3 + x*y^2*z - 5*y^4, [x, y, z], LexOrder),
degreevec(x^3 + x*y^2*z - 5*y^4, [x, y, z], DegreeOrder),
degreevec(x^3 + x*y^2*z - 5*y^4, [x, y, z], DegInvLexOrder)

Example 3

The exponent vector of the zero polynomial is a list of zeroes:

degreevec(0, [x, y, z])

Parameters

p

A polynomial of type DOM_POLY

f

A polynomial expression

vars

A list of indeterminates of the polynomial: typically, identifiers or indexed identifiers

order

The term ordering: either LexOrder, or DegreeOrder, or DegInvLexOrder, or a user-defined term ordering of type Dom::MonomOrdering. The default is the lexicographical ordering LexOrder.

Return Values

List of nonnegative integers. FAIL is returned if the input cannot be converted to a polynomial.

Overloaded By

f, p

See Also

MuPAD Functions

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