Ctadel: Symbolic Simplification

Generation of efficient codes for numerical problems requires extensive simplification of commuting operators (through operator commuting diagrams).

For example, the rule

æ
è
B
å
I = A 
X ö
ø
+ æ
è
B
å
I = A 
Y ö
ø
Þ B
å
I = A 
(X+Y)
is specified in Ctadel as
sum(X,I=A..B) + sum(Y,I=A..B) => sum(X+Y,I=A..B)
can be applied on the expression
æ
è
m
å
j = 1 
æ
è
n
å
i = 1 
uij ö
ø
ö
ø
+ æ
è
n
å
i = 1 
vi ö
ø
resulting in
n
å
i = 1 
æ
è
æ
è
m
å
j = 1 
uij ö
ø
+vi ö
ø
because the sum operation is ``self-commuting''.

This means that LHS of transformation rules can be specified independently of the operator commuting properties.

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File translated from TEX by TTH, version 2.21.
On 8 Oct 1999, 14:27.