grey/BOSL2
1
0
Fork 0
mirror of https://github.com/BelfrySCAD/BOSL2.git synced 2024-12-29 16:29:40 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

doc addition

Browse source
This commit is contained in:
Adrian Mariano 2021-05-21 20:21:50 -04:00
parent 19c521913d
commit 16ec2ecbd6
1 changed files with 8 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
math.scad
View file

@ -1838,12 +1838,19 @@ function _poly_roots(p, pderiv, s, z, tol, i=0) =
// parts are zero. You can specify eps, in which case the test is
// z.y/(1+norm(z)) < eps. Because
// of poor convergence and higher error for repeated roots, such roots may
// be missed by the algorithm because their imaginary part is large.
// be missed by the algorithm because their imaginary part is large.
// Arguments:
// p = polynomial to solve as coefficient list, highest power term first
// eps = used to determine whether imaginary parts of roots are zero
// tol = tolerance for the complex polynomial root finder
// The algorithm is based on Brent's method and is a combination of
// bisection and inverse quadratic approximation, where bisection occurs
// at every step, with refinement using inverse quadratic approximation
// only when that approximation gives a good result. The detail
// of how to decide when to use the quadratic came from an article
// by Crenshaw on "The World's Best Root Finder".
// https://www.embedded.com/worlds-best-root-finder/
function real_roots(p,eps=undef,tol=1e-14) =
assert( is_vector(p), "Invalid polynomial." )
let( p = _poly_trim(p,eps=0) )