/* EU_A.G: procedure to return (deterministic,publicly observable) component of
           player a's expected utility function, which depends on player a's 
	   belief of the probability that player b will confess, p_b. 
	   Private information part is an additive extreme value distributed 
	   shock known to prisoner a but not to prisoner b. Symmetrically, 
           prisoner a does not know prisoner b's private type, and so from the
	   standpoint of prisoner a, prisoner b decision to confess is probabilistic,
	   a result of b's private information which prisoner a does not observe.

	  Inputs: 

	  d_a: decision of prisoner a, 1 = confess, 0= don't confess
	  d_b: decision of prisoner b, 1 = confess, 0= don't confess
	  x_a: prisoner a's observable type, assumed to be restricted to [0,1]
	  p_b: prisoner a's belief of the probability that prisoner b will
	       confess, obviously restricted to the [0,1] interval

	  John Rust, University of Maryland, November, 2005 */

   proc (1)=eu_a(d_a,x_a,p_b);


       if ((d_a == 1));

            retp (p_b*u_a(1,1,x_a)+(1-p_b)*u_a(1,0,x_a));

       else;

            retp (p_b*u_a(0,1,x_a)+(1-p_b)*u_a(0,0,x_a));

       endif;

   endp;