square root iterative

[onlyuros]

Aloha,

what would be the way to calculate the square root of a number e.g. A with precision E with formula X(0)=(A+1)/2, X(i)=(X(i-1) + A/X(i-1))/2, i=1,2,... ? Tnx!

 

[joel76]

What have you tried ?

 

[joel76]

You should have written :
X(0)=(1+A/1)/2,
X(i)=(X(i-1) + A/X(i-1))/2.
It is easier to see the recursion.

 

[onlyuros]

Ah yes, sorry. I have no idea how to do it since I'm quite new to prolog.

 

[joel76]

You can do it with a predicate of 4 arguments my_square_root/4 .
arg 1 : the number you're looking for the square_root.
arg 2 : epsilon
arg 3 : the current computed value of the square root
arg 3 : the final result