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Feature #1173

Upper bound for value of poly in an interval

Added by John Abbott about 6 years ago. Updated about 6 years ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
New Function
Target version:
Start date:
04 Apr 2018
Due date:
% Done:

0%

Estimated time:
Spent time:

Description

Write a function which accepts a (univariate) polynomial f (with rational coeffs), and an interval [a,b] with rational end points; the functions returns a rational which is an upper bound for max(f(x) | x in [a,b]) and perhaps also a lower bound for min(f(x) | x in [a,b]).


Related issues

Related to CoCoA-5 - Bug #1171: RealRoots: first point is sometimes wrong?Closed2018-04-03

Related to CoCoALib - Feature #1176: interval arithmeticIn Progress2018-04-05

History

#1 Updated by John Abbott about 6 years ago

  • Related to Bug #1171: RealRoots: first point is sometimes wrong? added

#2 Updated by John Abbott about 6 years ago

A while ago I read an article about this (perhaps "evaluating a polynomial over an interval"?). I no longer recall many details.

The main idea is to repeatedly subdivide the interval (not necessarily evenly), and recurse on the two "halves", then combine the results. The base case uses "Horner's algorithm" for intervals.

JAA believes that this could also be useful/interesting for the SC-Square project.

#3 Updated by John Abbott about 6 years ago

  • Description updated (diff)

#4 Updated by John Abbott about 6 years ago

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