# [Scilab-users] Division of uint8 matrix by a double matrix => segfault in scilab-branch-6.0 ?

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## [Scilab-users] Division of uint8 matrix by a double matrix => segfault in scilab-branch-6.0 ?

 Hello, I think I found a bug in the current 6.0 branch: a=uint8(rand(2,2)*255); b=rand(2,2); //let's be sure not to divide by 0 while or(b==0)      b=rand(2,2); end //adios amigo: Segmentation fault (core dumped) a./b Dividing a uint8 matrix by a double matrix is always causing a segfault on my machine. Can you reproduce this bug on your machine? Does anyone know whether it's a known bug or not? I have found : https://bugzilla.scilab.org/show_bug.cgi?id=15716 but it is not exactly the same (I don't do any division by zero, just element-wise division. Cheers, Antoine -- +++++++++++++++++++++++++++++++++++++++++++++++++++++++   Antoine Monmayrant LAAS - CNRS   7 avenue du Colonel Roche   BP 54200   31031 TOULOUSE Cedex 4   FRANCE   Tel:+33 5 61 33 64 59     email : [hidden email]   permanent email : [hidden email] +++++++++++++++++++++++++++++++++++++++++++++++++++++++ _______________________________________________ users mailing list [hidden email] http://lists.scilab.org/mailman/listinfo/users
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## Re: Division of uint8 matrix by a double matrix => segfault in scilab-branch-6.0 ?

 Le 10/09/2018 à 14:35, [hidden email] a écrit : > Hello, > > > I think I found a bug in the current 6.0 branch: > > a=uint8(rand(2,2)*255); > b=rand(2,2); > //let's be sure not to divide by 0 > while or(b==0) >     b=rand(2,2); > end > //adios amigo: Segmentation fault (core dumped) > a./b > > Dividing a uint8 matrix by a double matrix is always causing a > segfault on my machine. > Can you reproduce this bug on your machine? > Does anyone know whether it's a known bug or not? > > I have found : > https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/bugzilla.scilab.org/show_bug.cgi?id=15716  > but it is not exactly the same (I don't do any division by zero, just > element-wise division. > > > Cheers, > > > Antoine > Hello Antoine, Surely, this is a bug, but what type do you expect for the (eventual) result ? S. -- Stéphane Mottelet Ingénieur de recherche EA 4297 Transformations Intégrées de la Matière Renouvelable Département Génie des Procédés Industriels Sorbonne Universités - Université de Technologie de Compiègne CS 60319, 60203 Compiègne cedex Tel : +33(0)344234688 http://www.utc.fr/~mottelet_______________________________________________ users mailing list [hidden email] http://lists.scilab.org/mailman/listinfo/users
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## Re: Division of uint8 matrix by a double matrix => segfault in scilab-branch-6.0 ?

 Le 10/09/2018 à 14:50, Stéphane Mottelet a écrit : > Le 10/09/2018 à 14:35, [hidden email] a écrit : >> Hello, >> >> >> I think I found a bug in the current 6.0 branch: >> >> a=uint8(rand(2,2)*255); >> b=rand(2,2); >> //let's be sure not to divide by 0 >> while or(b==0) >>     b=rand(2,2); >> end >> //adios amigo: Segmentation fault (core dumped) >> a./b >> >> Dividing a uint8 matrix by a double matrix is always causing a >> segfault on my machine. >> Can you reproduce this bug on your machine? >> Does anyone know whether it's a known bug or not? >> >> I have found : >> https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/bugzilla.scilab.org/show_bug.cgi?id=15716  >> but it is not exactly the same (I don't do any division by zero, just >> element-wise division. >> >> >> Cheers, >> >> >> Antoine >> > Hello Antoine, > > Surely, this is a bug, but what type do you expect for the (eventual) > result ? I don't expect anything from this division, I don't think it makes much sense. :-) I just don't expect scilab to die when someone writes something like that! In fact, I discovered this bug while I was progressively changing the type of my variables from uint8 to double. As a side note, when dividing a uint8() by a double() matlab returns a uint8(), which is not really intuitive to me. Cheers, Antoine > > S. > -- +++++++++++++++++++++++++++++++++++++++++++++++++++++++   Antoine Monmayrant LAAS - CNRS   7 avenue du Colonel Roche   BP 54200   31031 TOULOUSE Cedex 4   FRANCE   Tel:+33 5 61 33 64 59     email : [hidden email]   permanent email : [hidden email] +++++++++++++++++++++++++++++++++++++++++++++++++++++++ _______________________________________________ users mailing list [hidden email] http://lists.scilab.org/mailman/listinfo/users
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## Re: Division of uint8 matrix by a double matrix => segfault in scilab-branch-6.0 ?

 In reply to this post by mottelet Le 10/09/2018 à 14:50, Stéphane Mottelet a écrit : > Le 10/09/2018 à 14:35, [hidden email] a écrit : >> Hello, >> >> >> I think I found a bug in the current 6.0 branch: >> >> a=uint8(rand(2,2)*255); >> b=rand(2,2); >> //let's be sure not to divide by 0 >> while or(b==0) >>     b=rand(2,2); >> end >> //adios amigo: Segmentation fault (core dumped) >> a./b >> >> Dividing a uint8 matrix by a double matrix is always causing a >> segfault on my machine. >> Can you reproduce this bug on your machine? >> Does anyone know whether it's a known bug or not? >> >> I have found : >> https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/bugzilla.scilab.org/show_bug.cgi?id=15716  >> but it is not exactly the same (I don't do any division by zero, just >> element-wise division. >> >> >> Cheers, >> >> >> Antoine >> > Hello Antoine, > > Surely, this is a bug, but what type do you expect for the (eventual) > result ? I reported a bug: https://bugzilla.scilab.org/show_bug.cgi?id=15759Can some or you try my test script for your OS/scilab version? Weirdly enough, under scilab 5.5.2, there is no segfault, but scilab complains about a division by zero (whereas there is no division by zero). Antoine > > S. > -- +++++++++++++++++++++++++++++++++++++++++++++++++++++++   Antoine Monmayrant LAAS - CNRS   7 avenue du Colonel Roche   BP 54200   31031 TOULOUSE Cedex 4   FRANCE   Tel:+33 5 61 33 64 59     email : [hidden email]   permanent email : [hidden email] +++++++++++++++++++++++++++++++++++++++++++++++++++++++ _______________________________________________ users mailing list [hidden email] http://lists.scilab.org/mailman/listinfo/users
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## Re: Division of uint8 matrix by a double matrix => segfault in scilab-branch-6.0 ?

 Le 10/09/2018 à 15:28, [hidden email] a écrit : > Le 10/09/2018 à 14:50, Stéphane Mottelet a écrit : >> Le 10/09/2018 à 14:35, [hidden email] a écrit : >>> Hello, >>> >>> >>> I think I found a bug in the current 6.0 branch: >>> >>> a=uint8(rand(2,2)*255); >>> b=rand(2,2); >>> //let's be sure not to divide by 0 >>> while or(b==0) >>>     b=rand(2,2); >>> end >>> //adios amigo: Segmentation fault (core dumped) >>> a./b >>> >>> Dividing a uint8 matrix by a double matrix is always causing a >>> segfault on my machine. >>> Can you reproduce this bug on your machine? >>> Does anyone know whether it's a known bug or not? >>> >>> I have found : >>> https://antispam.utc.fr/proxy/2/c3RlcGhhbmUubW90dGVsZXRAdXRjLmZy/bugzilla.scilab.org/show_bug.cgi?id=15716  >>> but it is not exactly the same (I don't do any division by zero, >>> just element-wise division. >>> >>> >>> Cheers, >>> >>> >>> Antoine >>> >> Hello Antoine, >> >> Surely, this is a bug, but what type do you expect for the (eventual) >> result ? > I reported a bug: https://bugzilla.scilab.org/show_bug.cgi?id=15759> Can some or you try my test script for your OS/scilab version? > Weirdly enough, under scilab 5.5.2, there is no segfault, but scilab > complains about a division by zero (whereas there is no division by > zero). Also, division (not element-wise division) gives a funny result, both for 5.5.2 and the current master: a=uint8(rand(2,2)*255); b=rand(2,2); //let's be sure not to divide by 0 while or(b==0)      b=rand(2,2); end //just a division : // master and scilab-6.0 : Operator / : Error -1 not yet managed. // 5.5.2 : !--error 26 //            Too complex recursion! (recursion tables are full) //            at line       9 of function %i_r_i called by :   ... a/b > > Antoine >> >> S. >> > -- +++++++++++++++++++++++++++++++++++++++++++++++++++++++   Antoine Monmayrant LAAS - CNRS   7 avenue du Colonel Roche   BP 54200   31031 TOULOUSE Cedex 4   FRANCE   Tel:+33 5 61 33 64 59     email : [hidden email]   permanent email : [hidden email] +++++++++++++++++++++++++++++++++++++++++++++++++++++++ _______________________________________________ users mailing list [hidden email] http://lists.scilab.org/mailman/listinfo/users
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## Re: Division of uint8 matrix by a double matrix => segfault in scilab-branch-6.0 ?

 In reply to this post by Antoine Monmayrant-2 Antoine, As requested, your script seems to produce the same results in Win 7 64-bit  Scilab 5.5.2 and 6.0.1, as you reported for Linux_x64. Regards, Rafael _______________________________________________ users mailing list [hidden email] http://lists.scilab.org/mailman/listinfo/users