Re: exercise in double number arithmetic

Hi again,
Here is another version, we haven't to save all the Pascal's triangle as
before.
Just two rows are sufficient.
Also, we can use locals (n, k) or values (n, k).
100 value M
create coeffs 2 M * 2* cells allot
: coeffs.init
    coeffs 2 M * 2* cells erase
    2 0 do 1. coeffs i M * 2* cells + 2! loop ;
0 value k
0 value n
: coef.calc { n k -- }
     \ to k to n
     coeffs.init
     n 1+ 1 do
       k 1+ 1 do
         coeffs j 1-  2 mod   M  * i 1- + 2* cells + 2@
         coeffs j 1-  2 mod   M  * i    + 2* cells + 2@
         d+
         coeffs j     2 mod   M  * i    + 2* cells + 2!
       loop
     loop
     coeffs n 2 mod   M  * k + 2* cells + 2@ d.
;
42 21 coef.calc   538257874440  ok
68 34 coef.calc 28453041475240576740  ok
Ahmed