From: Jeff Strickrott <jstric01@cs...>  20030513 03:52:25

Hi All: I am not sure if I have fallen victim to your antispam effort, I am reposting my query. Since my last post, I have obtained and compiled clapack. At this point I must decide between: using the old VisSDK library and integrating clapack and an mpeg library, or integrating the required routines into vxl's vnl library. Can anyone answer my questions below and suggest a development path? Thanks in advance for the help. Regards Jeff Strickrott Multimedia Database Laboratory Dept. of Computer Science Florida International University Miami, FL >  Original Message  > Subject: Integration of portion of LAPACK/CLAPACK routines to vnl > Date: Fri, 09 May 2003 15:39:08 0400 > From: Jeff Strickrott <jstric01@...> > To: vxlusers@...,vxlmaintainers@... > > Hello All: > > I am new to the vxl environment and I am trying to port code that was > written to use the NAG numerical library and/or a subset of LAPACK and > need to have the following LAPACK/CLAPACK or NAG routines: > >  DSYEV  compute all eigenvalues and, optionally, eigenvectors of a > real symmetric matrix A. >  DGETRF  compute an LU factorization of a general MbyN matrix A > using partial pivoting with row interchanges. >  DGETRI  compute the inverse of a matrix using the LU factorization > computed by DGETRF. >  DGEEV  compute for an NbyN real nonsymmetric matrix A, the > eigenvalues and, optionally, the left and/or right eigenvectors. I > believe that your vnl_real_eigensystem will do the same thing. > >  F04AEF: calculates the accurate solution of a set of real linear > equations with multiple righthand sides using an LU factorization with > partial pivoting, and iterative refinement. That is given a set of real > linear equations AX = B , the routine first computes an LU factorization > of A with partial pivoting, PA =LU , where P is a permutation matrix, L > is lower triangular and U is unit upper triangular. An approximation to > X is found by forward and backward substitution. The residual matrix R > =B  AX is then calculated using additional precision, and a correction > D to X is found by solving LUD = PR . X is replaced by X + D and this > iterative refinement of the solution is repeated until full machine > accuracy has been obtained. > > My expertise is not with computer vision or numerical routines (yet :) > ) and I have the following questions: > 1. Would it be easier to just obtain CLAPACK and use the appropriate > routines from there? Has anyone compiled both CLAPACK and vnl together? > 2. Add the FORTRAN routines per the procedures in the appendix? > 3. What are (if any) the thread safety issues with vxl, and in > particular the vnl libraries? > 4. Any idea for a source for the F04AEF routine? > 5. Any other suggestions? > > Thanks in advance for the help. > > Regards > Jeff Strickrott > Multimedia Database Laboratory > Dept. of Computer Science > Florida International University > Miami, FL 