3228: Day Counter - Revision history

YZ100 at 20:20, 16 May 2026

2026-05-16T20:20:22Z

RG: removed incomplete notice

2026-05-14T01:20:22Z

removed incomplete notice

YZ100: /* Trivia */

2026-05-13T04:11:21Z

‎Trivia

2A01:119F:2A5:8D00:1C5B:89A5:6E78:4C59 at 08:18, 28 April 2026

2026-04-28T08:18:16Z

FaviFake: /* Trivia */ comemnt out per talk

2026-04-11T09:08:07Z

‎Trivia: comemnt out per talk

Somefan: chair sitters still levitating is an art style choice, shown in the past

2026-04-08T02:43:45Z

chair sitters still levitating is an art style choice, shown in the past

81.179.199.253: /* Explanation */ Overflow error may be caught by a hard-failure, or at least a signal, rather than travel the continuum between top-value an bottom-value (or vice-versa).

2026-04-07T22:06:08Z

‎Explanation: Overflow error may be caught by a hard-failure, or at least a signal, rather than travel the continuum between top-value an bottom-value (or vice-versa).

FaviFake: /* Explanation */ {{incomplete|The calculations by DL Draco Rex et al. in the Talk should be included in the explanation. Don't remove this notice too soon.}}

2026-04-07T16:11:48Z

‎Explanation: {{incomplete|The calculations by DL Draco Rex et al. in the Talk should be included in the explanation. Don't remove this notice too soon.}}

Elektrizikekswerk at 07:24, 7 April 2026

2026-04-07T07:24:33Z

Elektrizikekswerk: /* Explanation */ Added a little bit coherecne in the explanation - it still needs some polish

2026-04-07T07:24:19Z

‎Explanation: Added a little bit coherecne in the explanation - it still needs some polish

@@ Line 63: / Line 63: @@
 Strangely enough, when the comic was first published the sign number was −0.00000000000000017 days.{{actual citation needed}} It was changed later though, probably so that it would be more realistic, −0.00000000000000017 would correspond to the very last bit of mantissa being incorrect and only for numbers between 1 and 2 (not including 2), and operation (1-1) is unlikely to result in rounding errors, so the smallest difference from integer is usually higher, which would result in −0.00000000000000044 the smallest possible  rounding error for values between 2 and 4.
 -->
-{{comic discussion}}<noinclude>[[Category:Interactive comics]][[Category:Dynamic comics]]
+{{comic discussion}}<noinclude>
 [[Category:Programming]]
 [[Category:Math]]

← Older revision		Revision as of 01:20, 14 May 2026
Line 10:		Line 10:

	==Explanation==		==Explanation==
−
−	~~{{incomplete\|The calculations by DL Draco Rex et al. in the Talk should be included in the explanation. Don't remove this notice too soon.}}~~
−
	A common feature of an industrial setting is a prominent sign announcing how many days have elapsed since the last workplace accident. The sign is typically updated each day to a number one higher — or back to zero, if there ''has'' been an accident. Such signs are intended to foster a culture of safety among the workers in the facility, since presumably no one wants to suffer the embarrassment of being the one to have caused an accident that resets the number to 0. (However, it may also lead workers to cover up or conceal accidents, for the same reason, which would tend to increase future accidents, because they do not report the need to correct hazardous conditions that are causing accidents.)		A common feature of an industrial setting is a prominent sign announcing how many days have elapsed since the last workplace accident. The sign is typically updated each day to a number one higher — or back to zero, if there ''has'' been an accident. Such signs are intended to foster a culture of safety among the workers in the facility, since presumably no one wants to suffer the embarrassment of being the one to have caused an accident that resets the number to 0. (However, it may also lead workers to cover up or conceal accidents, for the same reason, which would tend to increase future accidents, because they do not report the need to correct hazardous conditions that are causing accidents.)

@@ Line 60: / Line 60: @@
 In the comic, such an error creates the ridiculous illusion that −0.00000000000000044 days have passed, which implies a 'negative' number of days, which is impossible{{cn}}. It also, even if it were a positive number, would mean that much less than a nanosecond had passed since the last error, which would be an unfeasably short amount of time. Of course, the joke is that in making the sign showing the amount of time since a floating point error was last made, they are creating a floating point error, meaning the sign maintains its own "error state" in a self-referential way. Also, if they tried to reset the sign, they might make the same error again, repeating the cycle over and over, which would not be ideal.
-Coincidentally enough, [[Cueball]] is also floating — off his seat in this case, but this is an art style choice that ended up being apparent, as [[919|many]] [[1682|past]] [[1411|chair]] [[2362|sitters]] [[2382|are]] [[1088|shown]] [[1121|to]] [[3198|levitate]].
+Coincidentally enough, [[Cueball]] is also floating — off his seat in this case, but this is an art style choice that ended up being apparent, [[3100|as]] [[919|many]] [[1682|past]] [[1411|chair]] [[2362|sitters]] [[2382|are]] [[3178|also]] [[1088|shown]] [[1121|to]] [[3198|levitate]].
 <!--

← Older revision		Revision as of 08:18, 28 April 2026
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	The program starts with the number 19, and subtracts 1.9 from it, ten times. Mathematically, we would expect the result to be 0. However, the number 1.9 cannot be represented exactly in binary, nor can the intermediate results 17.1, 15.2, 13.3, etc. The cascading roundoff errors conspire to produce a result of −0.00000000000000044 instead of the expected 0.		The program starts with the number 19, and subtracts 1.9 from it, ten times. Mathematically, we would expect the result to be 0. However, the number 1.9 cannot be represented exactly in binary, nor can the intermediate results 17.1, 15.2, 13.3, etc. The cascading roundoff errors conspire to produce a result of −0.00000000000000044 instead of the expected 0.
		+
		+	Another possibility is that the timestamps were rounded to an intermediate lower precision that ended up rounding above the actual time value:
		+
		+	#include <stdio.h>
		+	float last_fp_error=0;
		+	int main(){
		+	double time = 0.00000000745058193;
		+	int a=3; int b=-2; double f=10;
		+	if(a/f+b/f!=(a+b)/f) last_fp_error=time;
		+	printf("It has been %.17f days since our last floating point error",time-last_fp_error);
		+	}

	In the comic, such an error creates the ridiculous illusion that −0.00000000000000044 days have passed, which implies a 'negative' number of days, which is impossible{{cn}}. It also, even if it were a positive number, would mean that much less than a nanosecond had passed since the last error, which would be an unfeasably short amount of time. Of course, the joke is that in making the sign showing the amount of time since a floating point error was last made, they are creating a floating point error, meaning the sign maintains its own "error state" in a self-referential way. Also, if they tried to reset the sign, they might make the same error again, repeating the cycle over and over, which would not be ideal.		In the comic, such an error creates the ridiculous illusion that −0.00000000000000044 days have passed, which implies a 'negative' number of days, which is impossible{{cn}}. It also, even if it were a positive number, would mean that much less than a nanosecond had passed since the last error, which would be an unfeasably short amount of time. Of course, the joke is that in making the sign showing the amount of time since a floating point error was last made, they are creating a floating point error, meaning the sign maintains its own "error state" in a self-referential way. Also, if they tried to reset the sign, they might make the same error again, repeating the cycle over and over, which would not be ideal.

@@ Line 51: / Line 51: @@
 Coincidentally enough, [[Cueball]] is also floating — off his seat in this case, but this is an art style choice that ended up being apparent, as [[919|many]] [[1682|past]] [[1411|chair]] [[2362|sitters]] [[2382|are]] [[1088|shown]] [[1121|to]] [[3198|levitate]].
 Strangely enough, when the comic was first published the sign number was −0.00000000000000017 days.{{actual citation needed}} It was changed later though, probably so that it would be more realistic, −0.00000000000000017 would correspond to the very last bit of mantissa being incorrect and only for numbers between 1 and 2 (not including 2), and operation (1-1) is unlikely to result in rounding errors, so the smallest difference from integer is usually higher, which would result in −0.00000000000000044 the smallest possible  rounding error for values between 2 and 4.
+-->
 {{comic discussion}}<noinclude>[[Category:Interactive comics]][[Category:Dynamic comics]]
 [[Category:Programming]]

@@ Line 21: / Line 21: @@
 This issue is exacerbated on computers which use binary arithmetic (i.e., virtually all computers today), since in binary, the ordinary fraction 1/10 is represented as the infinitely-repeating base-2 fraction <tt>0.000110011001100110011</tt>….  A classic example is that, depending on circumstances, the calculation 0.1 + 0.2 might [https://stackoverflow.com/questions/588004/is-floating-point-math-broken seem to give an answer of 0.30000000000000004].
-Floating point errors are particularly common in programming, especially in languages that implicitly convert decimal numbers to binary floating point, so an approximation is already made at conversion leading to unexpected results. The title text cites another common programming problem, integer overflow. When a value  gets bigger than the biggest integer that can be represented in a certain format, it typically "wraps around" to the smallest value. In case of 32-bit signed integers it may wrap from 2<sup>31</sup>−1 (2,147,483,647) to −2<sup>31</sup> (−2,147,483,648).
+Floating point errors are particularly common in programming, especially in languages that implicitly convert decimal numbers to binary floating point, so an approximation is already made at conversion leading to unexpected results. The title text cites another common programming problem, integer overflow. When a value  gets bigger than the biggest integer that can be represented in a certain format, it may "wrap around" to the smallest/most negative value (if the system is not instead set to catch this as an overflow error). In case of 32-bit signed integers it may wrap from 2<sup>31</sup>−1 (2,147,483,647) to −2<sup>31</sup> (−2,147,483,648).
 Integer overflow was the topic of [[571: Can't Sleep]], with yet another example of a 'days since' sign being [[3140: Biology Department]] (two examples, in both the comic and its title text).

@@ Line 11: / Line 11: @@
 ==Explanation==
-{{incomplete|This page was created -.000000000000000032 days ago. Don't remove this notice too soon.}}
+{{incomplete|The calculations by DL Draco Rex et al. in the Talk should be included in the explanation. Don't remove this notice too soon.}}
 A common feature of an industrial setting is a prominent sign announcing how many days have elapsed since the last workplace accident.  The sign is typically updated each day to a number one higher — or back to zero, if there ''has'' been an accident.  Such signs are intended to foster a culture of safety among the workers in the facility, since presumably no one wants to suffer the embarrassment of being the one to have caused an accident that resets the number to 0. (However, it may also lead workers to cover up or conceal accidents, for the same reason, which would tend to increase future accidents, because they do not report the need to correct hazardous conditions that are causing accidents.)

@@ Line 8: / Line 8: @@
 | titletext = It has been −2,147,483,648 days since our last integer overflow.
 }}
 ==Explanation==