(part-type 'rc
	   '()
	   '()
	   '((any-model
	      (n1 n2 n3)
	      ((v    voltage-source  n1 n3)
	       (r    resistor        n1 n2)
	       (c    capacitor       n2 n3))
	      ()
	      ())))

(define rctest
  (create-circuit 'RC 'rc '(impedance)))



(assume-value rctest '(resistance r) 2.0)

(assume-value rctest '(capacitance c) 3.0)

(assume-value rctest '(current t1 r impedance) 1.0)

(assume-value rctest '(potential n3 impedance) 'a)

(propagate (constraint-network rctest))

(pe ((the-value rctest '(voltage v impedance)) 's))
(+ 2 (/ 1/3 s))

(pe (magnitude ((the-value rctest '(voltage v impedance)) (* +i 10))))
2.0002777584903333