/GrADS/script/dayofyear.gsf

ret = dayofyear( time )
ret = dayofyear( day-of-year )

test.gs

rc = gsfallow( 'on' )
say dayofyear( '15mar2004' )
ga-> test
75

test.gs

rc = gsfallow( 'on' )
say dayofyear( 360 )
ga-> test
26Dec