# [Maxima] Problematic expression for expand

Robert Dodier robert.dodier at gmail.com
Mon Jun 15 15:15:53 CDT 2009

Hello, I find the following expression is problematic for expand
in the sense that it takes a tremendously long time and a very
great amount of memory. What makes it so difficult?

Is there a way to expand it from the leaves upward?
I tried to figure out a way to apply a function from the
bottom up, but I couldn't figure it out.

Incidentally this expression originates from trying to construct
a cubic spline (the cspline function in package interpol) from
some points like [%pi/2, %pi].

Thanks for any insights,

Robert Dodier

((2/%pi-1)*(((%pi/2-1)/(%pi-1)-1)
*((6*(2/%pi-2*(4-%pi)/%pi)/%pi
-(6*(2*(4-%pi)/%pi-(%pi-2)/(%pi/2-1))/(%pi-1)
-6*((%pi-2)/(%pi/2-1)-2)*(%pi/2-1)/(%pi*(%pi-1)))
/(2*((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2)))
/(((%pi/2-1)/(%pi-1)-1)
/(2*((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2))
+2)
-(6*(2*(2*%pi-5)/%pi-2/%pi)/%pi
-(6*(2/%pi-2*(4-%pi)/%pi)/%pi
-(6*(2*(4-%pi)/%pi-(%pi-2)/(%pi/2-1))/(%pi-1)
-6*((%pi-2)/(%pi/2-1)-2)*(%pi/2-1)/(%pi*(%pi-1)))
/(2*((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2)))
/(2*(((%pi/2-1)/(%pi-1)-1)
/(2*((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2))
+2)))
/(2*(2-1/(4*(((%pi/2-1)/(%pi-1)-1)
/(2*((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2))
+2)))
*(((%pi/2-1)/(%pi-1)-1)
/(2*((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2))
+2)))
/((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2)
+(6*(2*(4-%pi)/%pi-(%pi-2)/(%pi/2-1))/(%pi-1)
-6*((%pi-2)/(%pi/2-1)-2)*(%pi/2-1)/(%pi*(%pi-1)))
/((2/%pi-1)*(%pi/2-1)/(2*(%pi-1))+2))
/2
+6*((%pi-2)/(%pi/2-1)-2)/%pi)
*(x^3-x)
/6
+2*x