CoCoA:RealRootRefine

RealRootRefine

refine a real root of a univariate polynomial

Description

This function computes a refinement of a real root of a univariate

polynomial over Q to the desired precision (width of isolating

interval). The starting root must be a record produced by <ttref>RealRoots</ttref>.

Example

  RR := RealRoots(x^2-2);
  RealRootRefine(RR[1], 1/2);
Record[ CoeffList = [-8, 1456, -712], Inf = -91/64, Sup = -45/32]
-------------------------------
  RR := [RealRootRefine(Root, 10^(-20)) | Root In RR];
  FloatStr(RR[1].Inf);
-1.414213562*10^0
-------------------------------

Syntax

RealRootRefine(Root:RECORD, Precision:RAT):RECORD

RealRoots

RealRootsApprox

RootBound

   <type>polynomial</type>