up previous next
RealRootRefine

refine a real root of a univariate polynomial
Syntax
          
RealRootRefine(Root:RECORD, Precision:RAT):RECORD

          

Description
This function computes a refinement of a real root of a univariate polynomial over QQ to the desired precision (width of isolating interval). The starting root must be a record produced by RealRoots .

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
-------------------------------


See Also