Posted By
SVS
on 2004-12-27
04:01:36
 |  Math error?
Type:
10 a=10^3
20 b%=1000/a
30 print b%
result is 0 instead of 1
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Posted By
MIK
on 2004-12-27
04:58:58
 | Re: Math error?
Only a Professor could work this out Mr SVS.
To be honest I wouldn't have a clue. 1+1=3? 
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Posted By
Csabo
on 2004-12-27
08:51:37
| Re: Math error?
Nice find. The problem seems to be in the "power of" function. You can force the poor old Plus/4 to admit it even without a division, just write:
? 100 = 10^2
(Where ^ is SHIFT+zero of course). This will evaluate to false. So one wonders what the differnce between 100 and 100 is, so let's see:
? 10^2 - 100
The answer of course is 2.98023224E-08 I guess the real problem lies in the fact that 100 is stored internally as an integer number, but 10^2 is not.
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Posted By
SVS
on 2004-12-27
10:37:30
| Re: Math error?
@Csabo
... not exactly. If you store 10.000.000 the result is OK,
on the contrary if you store 10^7 result is wrong.
The bug seems to be on powering not on floating point operations.
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Posted By
JamesC
on 2004-12-27
13:08:50
| Re: Math error?
By using A% (integer variable), the answer is correct. If you are sure that the result will always be in the range covered by % variables, -/+ 32767 I believe, then this should be safe.
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Posted By
Ulysses777
on 2004-12-27
13:10:45
| Re: Math error?
Try this...
10 A=10^3
20 B=1000
30 IF A=B THEN PRINT"Y":ELSE PRINT"X"
It should print Y, but it prints X. However, if you change A to A%, it works.
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Posted By
SVS
on 2004-12-28
03:39:21
| Re: Math error?
The bug applies to numbers greater than integer range (32767) too. 10^7, 10^8 give the same wrong results. Only 10^2 and 10^1 are correct but probably because they are too small then the rounding is insignificant.
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Posted By
Litwr
on 2004-12-29
06:01:46
| Re: Math error?
1. n^m = e^(m*ln(n))
2. e^x = 1 + x + x^2/2 + x^3/6 + x^4/4! + ...
3. e = 2.718...
4. This floating point operations and number e are infinite so we and computers must stay after several steps and lose accuracy.
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Posted By
Austin
on 2005-01-07
15:33:12
| Re: Math error?
Can I just say how clever I think you all are ! Happy new year...
A.
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