On Wed, Nov 19, 2008 at 10:58 PM, Scott Sinclair <scott.sinclair.za@ gmail.com> wrote:
> 2008/11/20 Charles R Harris <[EMAIL PROTECTED]>: > > > > On Wed, Nov 19, 2008 at 3:20 PM, Fabrice Silva <[EMAIL PROTECTED]> > > wrote: > >> > >> Le mercredi 19 novembre 2008 à 14:27 -0500, Alan G Isaac a écrit : > >> > So my question is not just what is the algorithm > >> > but also, what is the documentation goal? > >> > >> Concerning the algorithm (only): > >> in Joshua answer, you have might have seen that solve is a wrapper to > >> lapack routines *gesv (z* or d* depending on the input type). > > > > Which, IIRC, calls *getrf to get the LU factorization of the lhs matrix > A. > > Here: > > > > * DGESV computes the solution to a real system of linear equations > > * A * X = B, > > * where A is an N-by-N matrix and X and B are N-by-NRHS matrices. > > > > * > > * The LU decomposition with partial pivoting and row interchanges is > > * used to factor A as > > * A = P * L * U, > > * where P is a permutation matrix, L is unit lower triangular, and U is > > * upper triangular. The factored form of A is then used to solve the > > > > * system of equations A * X = B. > > * > > It's not always fun to read the code in order to find out what a > function does. So I guess the documentation goal is to eventually add > sufficient detail, for those who want to know what's happening without > diving into the source code. > > A Notes section giving an overview of the algorithm has been added to > the docstring http://docs.scipy.org/numpy/docs/numpy.linalg.linalg.solve/. > > I didn't feel comfortable quoting directly from the LAPACK comments, > so maybe someone else can look into adding more detail. > Looks fine to me. Chuck
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