symbolic.py: wip p_nosing

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/symbolic.py b/symbolic.py
index c3d89db5edb0176d6019c709b58ab064576dc707..c70cda631a6bdf74213a58e8c8c105d8210b68db 100755 (executable)
--- a/symbolic.py
+++ b/symbolic.py
@@ -21,6 +21,24 @@ p_start = Matrix([
   mu * s,
 ])
 
-p_rightvars = p_start.subs(theta, s/r).subs(r, 1/la)
+p_rightvars = p_start.subs( theta, s/r ).subs( r, 1/la )
 
 pprint(p_rightvars)
+
+dirn_rightvars = diff(p_rightvars, s)
+
+pprint(dirn_rightvars)
+
+zeta = Wild('zeta')
+
+p_nosing = (p_rightvars
+            .replace( 1-cos(zeta)  ,   2*sin(zeta/2)**2          )
+            .replace( sin(zeta)**2 ,   zeta*sinc(zeta)*sin(zeta) )
+            )
+p_nosing[1] = (p_nosing[1]
+            .replace( sin(zeta) , zeta * sinc(zeta)                )
+               )
+
+print
+pprint(p_nosing,)
+