On Friday 26 September 2003 05:56, Alan W. Irwin wrote:
| On 2003-09-26 00:38+0100 Jo=E3o Cardoso wrote:
| > On Thursday 25 September 2003 23:36, Pavel Sakov wrote:
| > | Hi Folks,
| > |
| > | I probably should have been more explicit in my message to Joao.
| > |
| > | I checked svd.f from EISPACK, and this file is equivalent to
| > | svdcmp() from NR. I mean, it is the source of the svd code in NR.
| > | The NR authors did not even bother to rename the variables.
| > Shameful!
| Actually not. They gave full credit in the NR book to prior work,
| and that is all that is required. That prior work was all free so NR
| could make small changes to the fortran source, convert to C and
| relicense the code in any way they chose.
| To avoid that bad license, we just have to steer completely clear of
| both the fortran and C NR versions and go back and rederive what we
| need directly from EISPACK fortran source using f2c.
I'm pretty satisfied with Pavel's approach to solve the problem, as the=20
following highlights from private e-mails show. When I will sync PLplot=20
with Pavel's csa everything will be OK:
pavel > However, as you suggested, one can use the original code from=20
EISPACK, and that is what I have done.
pavel > Compared with the previous version of SVD code in csa, most=20
of the changes were pretty cosmetic.=20
pavel > The only thing that arguably was borrowed from NR was the=20
idea of rewriting the input matrix A by output matrix U. [jc: =20
but this is normal practice in other fortran routines, if I=20
jc > But you will change the NR credits in the source file, asserting =
the facts, right?
pavel > After syncing the code with EISPACK, I changed the credits to=20
pavel > Correction -- there is a reference to EISPACK Guide in the=20
Does everybody agree?