On 8/23/05, rand huso <[EMAIL PROTECTED]> wrote: > Phil, et alia, > > Thanks for the response. This is the first time I've submitted any > code to any community for review and potential inclusion in any > open-source project, I usually just create stuff for my own use. > > <background> > Matrix inverses in the traditional sense: > (A) * x = b > The inverse (~A) and the original matrix (A) should have these properties: > (A) * (~A) * (A) = (A), or more generally: > (A) * (~A) = (I) the identity matrix. Just as: > (~A) * (A) * (~A) = (~A), or more generally: > (~A) * (A) = (I) > Matrices that are "singular" (where one or more equations is a > combination of other equations) or that aren't "square" (having the > same number of equations as unknowns) are not generally solvable by > traditional methods. May those methods Rest In Peace. > </background> > > When I use my matrix routines I expect: > x = (~A) * b, no matter what the original (A) was... sparce, singular, > non-square > > I don't use return codes to indicate problems with doing an inverse... > I just do the inverse. I haven't found a matrix yet that I couldn't > invert (the exception might be a matrix entirely consisting of 0.0 - > but even that should work - it would just be a check on boundary > conditions). > > The matrix routine I attached last time would provide an inverse for > any input matrix. It really shouldn't matter if the matrix is singular > or not. If the matrix is singular, it just means there's more than one > equation. Using the attached routines would return the inverse, and > using one of the other methods would return a matrix that represents > the null-space of the original matrix.
Unfortunately, the attachment did not make it with your message above. It would be better to attach code to a Bugzilla ticket, as indicated in the link above. It looks like you are referring to a generalized matrix inverse algorithm. The best way to get started with this would be to first add an entry to the WishList (again, see instructions in the developer's guide), including a reference or two describing the algorithm that you would like to implement, and, most importantly, the precise definition of what the algorithm computes. Then follow up here again to see if there is interest in adding this to commons-math. Thanks! Phil --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
