Is there a built in general recurrence sequence function like the binary recurrence sequence?
def a(n):
return BinaryRecurrenceSequence(a,b,c,d)returns the sequence U0=c, U1=d, and Un=aUn−1+bUn−2.
I would like something that returns Un=aUn−1+bUn−2+cUn−3
Any help is much appreciated!
If you need to compute Un efficiently - here is a way:
a=1
b=2
c=3
u0=u1=u2=1 # initial values
x = polygen(QQ)
C = companion_matrix(x^3-a*x^2-b*x-c)
def U(n):
return (vector([u0,u1,u2]) * C^n)[0]Alternatively you can use LFSR as described at https://doc.sagemath.org/html/en/refe...
Asked: 1 year ago
Seen: 155 times
Last updated: Mar 19 '24
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