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Floating Point Error
- To: firstname.lastname@example.org
- Subject: Floating Point Error
- From: Walker Sigismund <email@example.com>
- Date: Sat, 14 Aug 93 14:06 GMT0BST-1
- Reply-to: firstname.lastname@example.org
Some weeks ago I reported a bug which has annoyed me for some time
the source of which I believe I have now tracked down. The bug is
? (/ 0.0)
? (/ 0.0)
> Error: Can't divide by zero.
> While executing: /
> Type Command-. to abort.
See the RestartsI menu item for further choices.
Mainly this causes formatting mistakes, but it can lead to some
potentially serious numerical problems. For example
In a standard regression test known as the Longley data set (which
is a tricky test set because the data is highly correlated) I get the
following differences in the Sum-of-Squares values depending on
whether the floating point bug that sometimes crops up has or not
1) when float bug not does not occur (/ 0.0) => > Error: Can't divide
(68445976650 834951.2065429687 6.844514169879346E+10 68260967824
| here is a problem it the second Sum-of-Squares
2) when not working properly (/ 0.0) => -1.7976931348623157E+308
(68445976650 832927.5610351562 6.8445143722438965E+10 68260967824
It appears that the floating-point bug occurs when I have Dove-Fax on
at Init time, which causes its init to find the serial port and test
the modem out... This occurs using Patch 2 on a clean copy of MCL.
I have the modem and Imagewriter Printer hooked up to separate power
switches so they are not always on at start up. When the Dove Fax
is, the bug occurs as soon as I launch MCL, otherwise it does not. It
does not occur when the Imagewriter alone is switched on. It also
does not happen if the fax is on, but the init is removed from the
extension folder. The dove fax version is 2.0.3.
Can anyone else reproduce this?