Kahan summation: Difference between revisions
add RPL
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simple summation of a,b,c = 1.0000000000000000000000000000001
Kahan summation of a,b,c = 1.0000000000000000000000000000000
</pre>
=={{header|RPL}}==
{| class="wikitable" ≪
! RPL code
! Comment
|-
|
≪ → input
≪ 0 0
1 input SIZE '''FOR''' j
input j GET SWAP -
DUP2 +
DUP 4 ROLL - ROT -
'''NEXT''' DROP
≫ ≫ '<span style="color:blue">∑KAHAN</span>' STO
≪ .1
'''WHILE''' 1 OVER + 1 ≠ '''REPEAT''' 10 / '''END'''
→ eps
≪ 1 eps + eps NEG +
1 eps eps NEG →LIST <span style="color:blue">∑KAHAN</span>
≫ ≫ '<span style="color:blue">TASK</span>' STO
|
<span style="color:blue">∑KAHAN</span> ''( { a b .. n } → a+b+..+n ) ''
var sum = 0.0, c = 0.0
for i = 1 to input.length do
var y = input[i] - c
var t = sum + y
c = (t - sum) - y
sum = t
next i ; return sum
Calculate epsilon
Display 1 + epsilon - epsilon
Display KAHAN( { 1 epsilon -epsilon })
|}
{{out}}
<pre>
2: 0.999999999999
1: 1
</pre>
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