Dear Patrice, Am 14.07.2015 um 12:29 schrieb Patrice MÉGRET: > > Is there any trouble in the cspline algorithm or do I make a mistake > somewhere? that is a bug in the cspline algorithm. At the time I had written the code I hadn't tested it thorougly. I'll try to fix it, but that could take some time. Sorry for this, Christoph