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Kahan summation algorithm
12-19-2014, 09:12 PM (This post was last modified: 12-19-2014 09:48 PM by Thomas Klemm.)
Post: #1
Kahan summation algorithm
For details please consult Wikipedia.

Program for the HP-42S:
Code:
00 { 19-Byte Prgm }
01 LBL "KAHAN"
02 +
03 ENTER
04 RCL+ ST Z
05 STO- ST Z
06 X<> ST Z
07 +
08 END

Worked example: \(10^{10}+\pi+e\)

CLST
E10
ENTER
0
PI
XEQ "KAHAN"
1
E↑X
R/S

y: 10,000,000,005.9
x: -0.04012551795


This is the correctly rounded result.

The classic addition is not the same:

E10
PI
+
1
E↑X
+

y: 0
x: 10,000,000,005.8


Cheers
Thomas
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Messages In This Thread
Kahan summation algorithm - Thomas Klemm - 12-19-2014 09:12 PM
RE: Kahan summation algorithm - Gerald H - 12-20-2014, 09:47 AM
RE: Kahan summation algorithm - Werner - 12-21-2014, 08:52 AM



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