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. Cheers, Scott _______________________________________________ Numpy-discussion mailing list [email protected] http://projects.scipy.org/mailman/listinfo/numpy-discussion
