Add analytical solution for DFOP-SFO

This is about twice as fast as deSolve compiled in the case of FOCUS D

1 files changed, 2 insertions, 0 deletions

diff --git a/NEWS.md b/NEWS.md
index 2512f361..49828447 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,6 +4,8 @@
 
 - 'mkinmod': Make 'use_of_ff' = "max" the default
 
+- Improve performance by a) avoiding expensive calls in the cost function like merge() and data.frame(), and b) by implementing analytical solutions for SFO-SFO and DFOP-SFO
+
 # mkin 0.9.49.11 (2020-04-20)
 
 - Increase a test tolerance to make it pass on all CRAN check machines