Hello Alex, There are two options in the LCF page that may help. If you don’t want any negative values try selecting “All weights between 0 and 1” and unselecting “Force weights to sum to 1”. Matt From: Ifeffit On Behalf Of Alexander Zherebker Sent: Wednesday, January 24, 2024 7:35 AM To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] bug in Athena Caution: This email originated from outside EPA, please exercise additional caution when deciding whether to open attachments or click on provided links. Hello! I faced an issue with 0.9.26 Athena. Doing LCF the option for weights doesn't really work so I keep getting negative components. Cheers, Alex