## Re: [Gramps-devel] Scandinavian (and not only) relationship calculators

 Re: [Gramps-devel] Scandinavian (and not only) relationship calculators From: Alex Roitman - 2004-07-30 14:07:23 Attachments: Message as HTML ```On 07/30/2004 06:03:04 AM, Lars Kr. Lundin wrote: > On Thu, Jul 29, 2004 at 02:18:41PM -0500, Alex Roitman wrote: > > > The [mf] strings have all the information. Here's how it works: suppose= we > > need to know the relation between person A and person B. We first find > > their closest common ancestor C and the [mf] path from A to C and from > > B to C. So, if you'd like to unroll the [mf] string from older to young= er=20 > > generation, you'll have sons and daughters. The other way it's mothers= =20 > > and fathers. >=20 > OK. So not only the construction, but also the parsing of the relationship > string regarding A and B involves C. Not necessarily C as a person, but definitely number of generations with=20 the genders of all participants from A to C and from B to C. > If we at a later stage want to support relations that are not through a > single person (currently a common ancestor [*]) the string parsing will be > tied to a number of persons apart from A and B. >=20 > If A is B's > > 3. cousins great-great- > > grandmothers grandchild. > the parsing of the resulting [mf]-string will require knowledge about > not only A and B, but also D (the 3. cousin), C (the common ancestor of > B & D) and E (the common ancestor of D & A). Wait a second, your 3. cousins great-great-grandmothers=20 grandchild is your first cousin once removed, or simply your great-great-grandmothers grandchild. This is because your 3. cousins great-great-grandmother is also=20 your great-great-grandmother. It's like saying "my father's son" which is either myself or my brother, or like "my grandfather's grandson" which could be me, my brother, or my cousin. In short, any relation should be explainable through the=20 closest common ancestor. While there could be many=20 alternative terms (father's son insetad of brother),=20 we don't have to list all of them. A single unambiguous=20 result should be good enough, I think.=20 > [*] is it checked if it is really two common ancestors ? That > would make the difference between a half-brother and a=20 > brother. Not yet, but we should be able to add it in the future. Alex --=20 Alexander Roitman http://ebner.neuroscience.umn.edu/people/alex.html Dept. of Neuroscience, Lions Research Building 2001 6th Street SE, Minneapolis, MN 55455 Tel (612) 625-7566 FAX (612) 626-9201 ```