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Re: [Pharo-project] Unexpected behavior of roundTo:

by Hilaire Fernandes

Well, whatever the underneath representation, one can expect roundedTo: 2 to return a float with two decimals. I am only interested in roundedTo: to display in the DrGeo canvas numbers. It was still funny to see sometimes number with 10 digits. Thanks for the info. Hilaire -- Education 0.2 -- http://blog.ofset.org/hilaire

April 8, 2011

Re: [Pharo-project] Unexpected behavior of roundTo:

by Nicolas Cellier

2011/4/8 Nicolas Cellier <nicolas.cellier.aka.nice(a)gmail.com>: > Once more, Floats are inexact. > Â Â 0.01 ~= 0.01s2 > The name #absPrintExactlyOn:base: is lying, it does not print exactly, > but it prints the shortest decimal representation than will be rounded > to the same Float when read back. > > To print it exactly, you need to use #printShowingDecimalPlaces: indeed. > As every finite Float is a represented internally as a Fraction with a > denominator being a power of 2, every finite Float has a decimal > representation with a finite number of decimals digits (just multiply > numerator and denominator with adequate power of 5, and you'll get the > digits). > > So try: > 0.01 printShowingDecimalPlaces: 59 > -> 0.01000000000000000020816681711721685132943093776702880859375 > Oh one thing I forgot, you wanna know how many digits you need after decimal point to print exactly ? Easy, (0.01 asTrueFraction denominator highBit - 1). Nicolas

April 8, 2011

Re: [Pharo-project] Issue 3971 in pharo: OBSystemBrowserAdaptor does not correctly find classes

by pharo＠googlecode.com

Comment #4 on issue 3971 by DougEdmu...(a)gmail.com: OBSystemBrowserAdaptor does not correctly find classes http://code.google.com/p/pharo/issues/detail?id=3971 I did find Ducasse in the classes. :) Attachments: find_class.png 16.0 KB

April 8, 2011

Re: [Pharo-project] Issue 3971 in pharo: OBSystemBrowserAdaptor does not correctly find classes

by pharo＠googlecode.com

Comment #3 on issue 3971 by renggli: OBSystemBrowserAdaptor does not correctly find classes http://code.google.com/p/pharo/issues/detail?id=3971 Ok, it is a subsequence (http://en.wikipedia.org/wiki/Subsequence) I am terribly sorry for using the wrong term.

April 8, 2011

Re: [Pharo-project] Unexpected behavior of roundTo:

by Nicolas Cellier

Pour enfoncer le clou, let's play a bit more with inexact representations: { ((2.8 asTrueFraction roundTo: 0.01 asTrueFraction) - (2.8 predecessor)) abs -> -1. ((2.8 asTrueFraction roundTo: 0.01 asTrueFraction) - (2.8)) abs -> 0. ((2.8 asTrueFraction roundTo: 0.01 asTrueFraction) - (2.8 successor)) abs -> 1. } detectMin: [:e | e key ] you get 0.0->1, which mean that: (2.8 asTrueFraction roundTo: 0.01 asTrueFraction) asFloat = (2.8 successor) But remember: (2.8 asTrueFraction roundTo: 0.01 asTrueFraction) ~= (2.8 successor) It must be interpreted as: the nearest Float to (2.8 asTrueFraction roundTo: 0.01 asTrueFraction) is (2.8 successor). If you want to know how far it is, then get an idea with: ((2.8 asTrueFraction roundTo: 0.01 asTrueFraction) - (2.8 successor) asTrueFraction) asFloat -2.0816681711721685e-16 Nicolas 2011/4/8 Schwab,Wilhelm K <bschwab(a)anest.ufl.edu>: > +1. Â This seems like an extension of "never test equality on floats." > > > > ________________________________________ > From: pharo-project-bounces(a)lists.gforge.inria.fr [pharo-project-bounces(a)lists.gforge.inria.fr] On Behalf Of Nicolas Cellier [nicolas.cellier.aka.nice(a)gmail.com] > Sent: Friday, April 08, 2011 1:14 PM > To: Pharo-project(a)lists.gforge.inria.fr > Subject: Re: [Pharo-project] Unexpected behavior of roundTo: > > Once more, Floats are inexact. > Â Â 0.01 ~= 0.01s2 > The name #absPrintExactlyOn:base: is lying, it does not print exactly, > but it prints the shortest decimal representation than will be rounded > to the same Float when read back. > > To print it exactly, you need to use #printShowingDecimalPlaces: indeed. > As every finite Float is a represented internally as a Fraction with a > denominator being a power of 2, every finite Float has a decimal > representation with a finite number of decimals digits (just multiply > numerator and denominator with adequate power of 5, and you'll get the > digits). > > So try: > 0.01 printShowingDecimalPlaces: 59 > -> 0.01000000000000000020816681711721685132943093776702880859375 > > You see that even if you try to execute the operation without rounding > error, then convert it back to Float, you get the error: > Â (2.8011416510246336 asTrueFraction roundTo: 0.01 asTrueFraction) asFloat > -> Â 2.8000000000000003 > > When you perform the #roundTo: operations in Float inexact arithmetic, > you may accumulate more rounding errors, so the result may vary. > > If you want to round to an exact hundredth, then use exact arithmetic and try: > Â 2.8011416510246336 roundTo: 0.01s2 > > Hope it helps to consider Float for what they are, inexact but fast. > Don't put too much expectations on them. > > Nicolas > > 2011/4/8 Hilaire Fernandes <hilaire.fernandes(a)gmail.com>: >> It looks like a known issue: >> >> printShowingDecimalPlaces: placesDesired >> Â Â Â Â "This implementation avoids any rounding error caused by rounded or >> roundTo: " >> Â Â Â Â ^ self asTrueFraction printShowingDecimalPlaces: placesDesired >> >> >> >> Le 08/04/2011 18:47, Hilaire Fernandes a Ã©crit : >>> 2.8011416510246336 roundTo: 0.01 >>> >>> returns >>> >>> Â 2.8000000000000003 >>> >>> >>> Tested with 1.2 >>> >>> >>> Should I fill a ticket, I don't see anythings similar? >>> >>> Hilaire >>> >> >> >> -- >> Education 0.2 -- http://blog.ofset.org/hilaire >> >> >> > > >

April 8, 2011

Re: [Pharo-project] Unexpected behavior of roundTo:

by Nicolas Cellier

Yes nice example to exhibit in school This again happens even if performed exactly (then rounded to nearest Float) (2.8 asTrueFraction roundTo: 0.01 asTrueFraction) asFloat As soon as you write 0.01 instead of (1/100) or (0.01s2), the worm is in the fruit. Nicolas 2011/4/8 Hilaire Fernandes <hilaire.fernandes(a)gmail.com>: > Even better: > > 2.8 truncateTo: 0.01 > -> 2.8000000000000003 > > > Le 08/04/2011 18:52, Hilaire Fernandes a Ã©crit : >> It looks like a known issue: >> >> printShowingDecimalPlaces: placesDesired >> Â Â Â "This implementation avoids any rounding error caused by rounded or >> roundTo: " >> Â Â Â ^ self asTrueFraction printShowingDecimalPlaces: placesDesired >> >> >> >> Le 08/04/2011 18:47, Hilaire Fernandes a Ã©crit : >>> 2.8011416510246336 roundTo: 0.01 >>> >>> returns >>> >>> Â 2.8000000000000003 >>> >>> >>> Tested with 1.2 >>> >>> >>> Should I fill a ticket, I don't see anythings similar? >>> >>> Hilaire >>> >> >> > > > -- > Education 0.2 -- http://blog.ofset.org/hilaire > > >

April 8, 2011

Re: [Pharo-project] Unexpected behavior of roundTo:

by Schwab,Wilhelm K

+1. This seems like an extension of "never test equality on floats." ________________________________________ From: pharo-project-bounces(a)lists.gforge.inria.fr [pharo-project-bounces(a)lists.gforge.inria.fr] On Behalf Of Nicolas Cellier [nicolas.cellier.aka.nice(a)gmail.com] Sent: Friday, April 08, 2011 1:14 PM To: Pharo-project(a)lists.gforge.inria.fr Subject: Re: [Pharo-project] Unexpected behavior of roundTo: Once more, Floats are inexact. 0.01 ~= 0.01s2 The name #absPrintExactlyOn:base: is lying, it does not print exactly, but it prints the shortest decimal representation than will be rounded to the same Float when read back. To print it exactly, you need to use #printShowingDecimalPlaces: indeed. As every finite Float is a represented internally as a Fraction with a denominator being a power of 2, every finite Float has a decimal representation with a finite number of decimals digits (just multiply numerator and denominator with adequate power of 5, and you'll get the digits). So try: 0.01 printShowingDecimalPlaces: 59 -> 0.01000000000000000020816681711721685132943093776702880859375 You see that even if you try to execute the operation without rounding error, then convert it back to Float, you get the error: (2.8011416510246336 asTrueFraction roundTo: 0.01 asTrueFraction) asFloat -> 2.8000000000000003 When you perform the #roundTo: operations in Float inexact arithmetic, you may accumulate more rounding errors, so the result may vary. If you want to round to an exact hundredth, then use exact arithmetic and try: 2.8011416510246336 roundTo: 0.01s2 Hope it helps to consider Float for what they are, inexact but fast. Don't put too much expectations on them. Nicolas 2011/4/8 Hilaire Fernandes <hilaire.fernandes(a)gmail.com>: > It looks like a known issue: > > printShowingDecimalPlaces: placesDesired > "This implementation avoids any rounding error caused by rounded or > roundTo: " > ^ self asTrueFraction printShowingDecimalPlaces: placesDesired > > > > Le 08/04/2011 18:47, Hilaire Fernandes a Ã©crit : >> 2.8011416510246336 roundTo: 0.01 >> >> returns >> >> 2.8000000000000003 >> >> >> Tested with 1.2 >> >> >> Should I fill a ticket, I don't see anythings similar? >> >> Hilaire >> > > > -- > Education 0.2 -- http://blog.ofset.org/hilaire > > >

April 8, 2011

Re: [Pharo-project] [Vm-dev] FW: Debugging Cog crash

by Schwab,Wilhelm K

"You still didn't answer where you got the VM." http://gforge.inria.fr/frs/download.php/28439/Pharo-1.2.1-CogOneClick.zip ________________________________________ From: pharo-project-bounces(a)lists.gforge.inria.fr [pharo-project-bounces(a)lists.gforge.inria.fr] On Behalf Of Schwab,Wilhelm K [bschwab(a)anest.ufl.edu] Sent: Friday, April 08, 2011 11:56 AM To: Pharo-project(a)lists.gforge.inria.fr; Squeak Virtual Machine Development Discussion Subject: Re: [Pharo-project] [Vm-dev] FW: Debugging Cog crash Levente, The image will not load at all. It simply dies with "Segmentation fault" - NOTHING else happens. gdb is maybe a possibility, but it is not an approach I ordinarily take, so some guidance would be helpful. I have a reproducible crash, but poor access to the affected box. Bill On Fri, 8 Apr 2011, Schwab,Wilhelm K wrote: > > Gratuitous default recipient... > > If there is a verbose dump option or other diagnostic efforts that will help, I will do my best to run them and report the results. I am fairly certain the vm is 'Croquet Closure Cog VM [CoInterpreter VMMaker-oscog.54]' (can verify later today), but this happened with an earlier Cog one-click too. There is something about the machine (UUID again?) that is different. I do not have root access to it, but I can get to a terminal. Ubuntu 10.10. Where did you download the VM? Does it crash when you're trying to evaluate [UUID new]? Did you try gdb? Levente ________________________________________ From: pharo-project-bounces(a)lists.gforge.inria.fr [pharo-project-bounces(a)lists.gforge.inria.fr] On Behalf Of Schwab,Wilhelm K [bschwab(a)anest.ufl.edu] Sent: Friday, April 08, 2011 11:42 AM To: Pharo-project(a)lists.gforge.inria.fr; Squeak Virtual Machine Development Discussion Subject: Re: [Pharo-project] [Vm-dev] FW: Debugging Cog crash Dave, It was, I did :) No help :( What else can I try? Bill ________________________________________ From: pharo-project-bounces(a)lists.gforge.inria.fr [pharo-project-bounces(a)lists.gforge.inria.fr] On Behalf Of David T. Lewis [lewis(a)mail.msen.com] Sent: Friday, April 08, 2011 10:32 AM To: Squeak Virtual Machine Development Discussion Cc: Pharo-project(a)lists.gforge.inria.fr Subject: Re: [Pharo-project] [Vm-dev] FW: Debugging Cog crash Yes, the libuuid.so bug would be a likely suspect. If the UUIDPlugin was built as an external library, just delete it and you will probably be good to go. If you need further info, look here: http://bugs.squeak.org/view.php?id=7358 Dave On Fri, Apr 08, 2011 at 07:58:39AM -0400, Schwab,Wilhelm K wrote: > > Gratuitous default recipient... > > If there is a verbose dump option or other diagnostic efforts that will help, I will do my best to run them and report the results. I am fairly certain the vm is 'Croquet Closure Cog VM [CoInterpreter VMMaker-oscog.54]' (can verify later today), but this happened with an earlier Cog one-click too. There is something about the machine (UUID again?) that is different. I do not have root access to it, but I can get to a terminal. Ubuntu 10.10. > > > ________________________________________ > From: Schwab,Wilhelm K > Sent: Friday, April 08, 2011 7:44 AM > To: Mariano Martinez Peck > Subject: RE: [Pharo-project] Debugging Cog crash > > Mariano, > > I first identified this problem/opportunity a while ago. At the time, there was no log - the vm just died. I can sniff around again as there might be one this time. My question at the time was whether there was something that I could enable to perhaps get more info. > > The output from the vm is, and I quote<g> "Segmentation fault". There is no other output. Perhaps it does not get far enough to have a call stack?? > > Bill > > > > ________________________________________ > From: Mariano Martinez Peck [marianopeck(a)gmail.com] > Sent: Friday, April 08, 2011 3:42 AM > To: Squeak Development Discussion Virtual Machine; Pharo Development > Cc: Schwab,Wilhelm K > Subject: Re: [Pharo-project] Debugging Cog crash > > also...shouldn't be a crash/dump file somewhere? > > can you write the output of the console where you invoke the VM into a file ? (using > to redirect) > > Cheers > > Mariano > > On Thu, Apr 7, 2011 at 11:10 PM, Schwab,Wilhelm K <bschwab(a)anest.ufl.edu<mailto:bschwab@anest.ufl.edu>> wrote: > Hello all, > > I have an account on an Ubuntu terminal server (at least I think that's what it would be called) running 10.10. The Cog one-click image crashes with "Segmentation fault" (if run from a terminal); the legacy VM seems to run the image nicely on the box. Any ideas? I will happily collect any facts that will be of help, but I need some > direction. > > Bill > > > > > > > -- > Mariano > http://marianopeck.wordpress.com

April 8, 2011

Re: [Pharo-project] Unexpected behavior of roundTo:

by Nicolas Cellier

Once more, Floats are inexact. 0.01 ~= 0.01s2 The name #absPrintExactlyOn:base: is lying, it does not print exactly, but it prints the shortest decimal representation than will be rounded to the same Float when read back. To print it exactly, you need to use #printShowingDecimalPlaces: indeed. As every finite Float is a represented internally as a Fraction with a denominator being a power of 2, every finite Float has a decimal representation with a finite number of decimals digits (just multiply numerator and denominator with adequate power of 5, and you'll get the digits). So try: 0.01 printShowingDecimalPlaces: 59 -> 0.01000000000000000020816681711721685132943093776702880859375 You see that even if you try to execute the operation without rounding error, then convert it back to Float, you get the error: (2.8011416510246336 asTrueFraction roundTo: 0.01 asTrueFraction) asFloat -> 2.8000000000000003 When you perform the #roundTo: operations in Float inexact arithmetic, you may accumulate more rounding errors, so the result may vary. If you want to round to an exact hundredth, then use exact arithmetic and try: 2.8011416510246336 roundTo: 0.01s2 Hope it helps to consider Float for what they are, inexact but fast. Don't put too much expectations on them. Nicolas 2011/4/8 Hilaire Fernandes <hilaire.fernandes(a)gmail.com>: > It looks like a known issue: > > printShowingDecimalPlaces: placesDesired > Â Â Â Â "This implementation avoids any rounding error caused by rounded or > roundTo: " > Â Â Â Â ^ self asTrueFraction printShowingDecimalPlaces: placesDesired > > > > Le 08/04/2011 18:47, Hilaire Fernandes a Ã©crit : >> 2.8011416510246336 roundTo: 0.01 >> >> returns >> >> Â 2.8000000000000003 >> >> >> Tested with 1.2 >> >> >> Should I fill a ticket, I don't see anythings similar? >> >> Hilaire >> > > > -- > Education 0.2 -- http://blog.ofset.org/hilaire > > >

April 8, 2011

Re: [Pharo-project] Unexpected behavior of roundTo:

by Hilaire Fernandes

Even better: 2.8 truncateTo: 0.01 -> 2.8000000000000003 Le 08/04/2011 18:52, Hilaire Fernandes a Ã©crit : > It looks like a known issue: > > printShowingDecimalPlaces: placesDesired > "This implementation avoids any rounding error caused by rounded or > roundTo: " > ^ self asTrueFraction printShowingDecimalPlaces: placesDesired > > > > Le 08/04/2011 18:47, Hilaire Fernandes a Ã©crit : >> 2.8011416510246336 roundTo: 0.01 >> >> returns >> >> 2.8000000000000003 >> >> >> Tested with 1.2 >> >> >> Should I fill a ticket, I don't see anythings similar? >> >> Hilaire >> > > -- Education 0.2 -- http://blog.ofset.org/hilaire

April 8, 2011