> I looked into this (the GNU doc on this is LONG!) but it is my > understanding that the GNU GPL can be used for commercial purposes.
Yes, it can be used for commercial software, but never for proprietary software. So you will need to offer end users (for your *entire* derived work) the same freedoms that you received with the GNU Scientific Library. The simplest (and almost universal) way to do that is to license your resulting program under the GPL.
