# Documentation get-cs

Hi all,

perhaps I’m looking in the wrong places - is there any documentation for the get-cs function?
I guess it is about getting the coefficient of stability of a vps.
According to this paper http://articles.ircam.fr/textes/Stroppa88a/index.pdf there should exist an s-space that get-cs is referring to. Is it documented somewhere or do I have to dive into the source code?

Thanks!

Just to complete this, in case someone else stumbles upon this: the definition of the s-space can be found in the file globals-vps.lisp in the chroma sources.
One interesting thing: in the paper mentioned above, CS is calculated using GILS whereas the file utils-vps.lisp in the chroma sources seems to use CILS. Can anyone elaborate on this?

Thanks!

Dear pfchph, Thank you for your thorough investigation of the VPS code I wrote almost a quarter of a century ago! The file you looked at, is a sort of “wrap-up” written when Chroma (the lisp-based version) was integrated into OM to become OMChroma. You are right that the name of the intervallic argument to “get-cs” is “cil”, which may be misleading, but this is just a name and it could have been anything. Indeed, as you pointed out, the CS is calculated using a GIL, so a GIL should be passed as an argument (to CIL…). You can see this clearly, for instance, in the method “get-cs” in the file “chord.lisp”.