theta_to_lambda_ARMA_03 = function(theta1,theta2,theta3){
#
# Written by:
# -- 
# John L. Weatherwax                2009-04-21
# 
# email: wax@alum.mit.edu
# 
# Please send comments and especially bug reports to the
# above email address.
# 
#-----

lambda1m = theta3
lambda0 = 1 + theta2 - 2 * theta3
lambda1 = 1 - theta1 - theta2 + theta3

return( c(lambda1m,lambda0,lambda1) )
  
}