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

 Re: [Gramps-devel] Scandinavian (and not only) relationship calculators From: Lars Kr.Lundin - 2004-07-30 16:35:27 ```On Fri, Jul 30, 2004 at 09:07:20AM -0500, Alex Roitman wrote: > Not necessarily C as a person, but definitely number of generations with > the genders of all participants from A to C and from B to C. > > 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 > grandchild is your first cousin once removed I apologize for not having expressed my thoughts more clearly. Clearly the current method works and is simple, when A & B have a known common ancestor. However, I think we should try to picture how things may look if GRAMPS have determined that A & B have _no_ known common ancestor and that they are instead related more distantly, f.ex. as in the example I gave above, where (and this is what I forgot to mention) E & C have no known common ancestor. Then GRAMPS will have to have the > number of generations with > the genders of all participants from A to E and from D to E and from D to > C and from B to C. The idea I had was to generate a relationship-path that is complete in its description. So in the above example the string would be a sequence of [mf]+ from A to E, and [ds]+ from E to D, and [mf]+ from D to C, and [ds]+ from C to B. Then that string is complete GRAMPS can translate the string with having to know anything about the generation counts. This is what I meant in my previous mail, but now I have an idea that may be better: Continue to use m and f (and p for a person with unknown gender) for the people in the relationship-path. For the common ancestor insert a meta-character, f.ex. upper-case: M or F for a single common ancestor with known gender P for a single common ancestor with unknown gender (rare) D for double common ancestors (common), i.e. when the common ancestor's two children in the relationship-path also share the other parent (should be a simple check to add). That means that when the parsing of the relationship-path meets a meta-character the interpretation of [mfp] changes from parent to child (or vice-versa) - and in addition there is a simple way to the determine/describe the relationships involving half-brothers/sisters. Anyway, I don't know if we ever want to support these kinds of relationship terms, but I think we should try to ensure that the design of the relationship-calculator will not prevent us from easily adding some functionality that may be wished for later. > > [*] is it checked if it is really two common ancestors ? That > > would make the difference between a half-brother and a > > brother. > > Not yet, but we should be able to add it in the future. Sounds good - especially since I would not yet know how to express these half-relationship terms in Danish :-) Now that I started, how about more tricky relationships like the following: A and a are sisters and B and b are brothers. A and B have a child C, and a and b have a child c. Now C and c are cousins through all 4 of their grandparents! How would we handle that? Have a nice week-end. -Lars Lundin. -- GEDCOMP: An extensive and free database for genealogists with interest in Denmark: http://www.lklundin.dk/gedcomp/ ```