misc::pslq

Heuristic detection of relations between real numbers

Use only in the MuPAD Notebook Interface.

This functionality does not run in MATLAB.

Syntax

misc::pslq(numberlist, precision)

Description

misc::pslq(numberlist, precision) returns a list of integers [k1, ..., kn] such that — denoting the elements of numberlist by a1, ..., an — the absolute value of is less than times the Euclidean norm of numberlist, or FAIL if such integers could not be detected.

This method can be used to get an idea about linear dependencies, before proving them.

Environment Interactions

misc::pslq is not affected by the current value of DIGITS. Numerical computations are carried out with more significant digits such that the output meets the specification given above.

Examples

Example 1

Does π satisfy a polynomial equation of degree at most 2 ?

misc::pslq([1, PI, PI^2], 20)

Example 2

Having forgotten the relation between sine and cosine, we can try the heuristic way.

misc::pslq([1, sin(0.32), sin(0.32)^2, cos(0.32), cos(0.32)^2], 10)

Parameters

numberlist

List of real numbers or objects that can be converted to real numbers by the function float.

precision

Positive integer

Return Values

List of integers, or FAIL

Algorithms

This function has been written by Raymond Manzoni.

The algorithm has been taken from Bailey and Plouffe, Recognizing numerical constants. See also Helaman R.P. Ferguson and David Bailey, A Polynomial Time, Numerically Stable Integer Relation Algorithm, RNR Technical Report RNR-92-032.

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