simple diode test
.param aa=10k
.param bb=aa/10
.param one=1
.param ten='(2+3)*4*.5'
V1   1  0  10.
R1   1  2  50.K
D1   2  0  ddd   1. 
R1   1  3  50.K
D2   3  0  dddd  1.
.model  ddd  d  ( is= 10.f  rs= 10k  n= 1.  tt= 0.  cjo= 0.  vj= 1.  m= 0.5 
+ eg= 1.11  xti= 3.  kf= 0.  af= 1.  fc= 0.5 )
.model  dddd  d  ( is= 10.f  rs= '10k/ten'  n= 1.  tt= 0.  cjo= 0.  vj= 1.  m= 0.5 
+ eg= 1.11  xti= 3.  kf= 0.  af= 1.  fc= 0.5 )
.print op v(nodes)
.op
.end