Quartic equation?

ROOT
1

Is there something in ROOT to solve a quartic equation ?

Thank you

Maxime

2

Maxime,

In the geometry package we have a function SolveQuartic (and Cubic).
In fact these functions could be staic functions placed somewhere else.
To use it, you can do

root [0] double v[4] root [1] TGeoTorus t Info in <TGeoManager::TGeoManager>: default geometry created root [2] t.SolveQuartic(-1.,1.,1.,-1.,v) (const Int_t)2 root [3]
or in case you have an old version of ROOT without system.rootmap

root [0] double v[4] root [1] gSystem->Load("libGeom"); root [2] TGeoTorus t Info in <TGeoManager::TGeoManager>: default geometry created root [3] t.SolveQuartic(-1.,1.,1.,-1.,v) (const Int_t)2

3

Thank you Rene, I would never have find it. I will take a look into it next monday.

By the way, but this is unimportant, there is a mistake in the documentation of the SolveQuartic function, the comments say :
Find real solutions of the quartic equation : x^3 + ax^2 + bx + c = 0
Input: a,b,c,d

of course, the equation solved is probably :
x^4 + ax^3 + bx^2 + c*x + d = 0

Maxime

4

Thanks for reporting the typo.
Now fixed in CVS and html page

Rene