84 ratpow

The package ratpow provides functions that return the coefficients of the numerator of a CRE polynomial in a given variable.

For example,

• ratp_coeffs(5*x^7-3*x^2+4,x) returns [[7,5],[2,-3],[0,4]], which omits zero terms;
• ratp_dense_coeffs(5*x^7-y*x^2+4,x) returns [5,0,0,0,0,-y,0,4], which includes zero terms;
• ratp_dense_coeffs((x^4-y^4)/(x-y),x) returns [1,y,y^2,y^3], because CRE simplifies the expression to x^3+y*x^2+y^2*x+y^3;
• ratp_dense_coeffs(x+sqrt(x),x) returns [1,sqrt(x)] while ratp_dense_coeffs(x+sqrt(x),sqrt(x)) returns [1,x]: in CRE form, x and sqrt(x) are treated as independent variables.

The returned coefficients are in CRE form except for numbers.

For the list of vars of a CRE polynomial, use showratvars. For the denominator of a CRE polynomial, use ratdenom.

For information about CREs see also rat, ratdisrep and showratvars.

• Functions and Variables for ratpow