Modified_History

Updates and changes
REAL 1.0 
First release on Github on June 27, 2019

Sept. 13, 2019
1. Consider Earth's ellipticity when calculating distance (gcarc)
2. Calculate and output azimuth for each station/pick and station azimuth gap for one event
3. Exclude events with large station gap.
4. Fix a bug

Nov. 14, 2019
1. Utilize stations within a specified distance (see: GCarc0)
2. Update code only, didn’t change the demo 

March 8, 2021
1. Use cos(latcenter) to balance distance in km for lat. and lon.
2. Eliminate event splitting using a different strategy

May 25, 2021 
Add a new constraint (replace previous nppp by npsboth0) to significantly improve the 
association reliability when station coverage is poor (through counting the number of stations 
with both P and S picks).

July 15, 2021
1. ouput refined locations and phases using a simulated annealing method
2. for event selection and pick selection, use distance weighted number of picks 
3. use rsel to remove outlier picks with large distance
4. add a new parameter drt 
5. add a new parameter nxd
6. add rweig and rnps in the code (default)
6. provide PhaseNet picker demo
7. provide hypoinverse location demo