[sage-support] Re: Arithmetic Progession syntax
sage: import scipy as sc sage: map(floor,sc.arange(0.0,1.2,0.1)) [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1] On 1 Kwi, 21:17, ObsessiveMathsFreak wrote: > Thanks for that, but I've run into another issue. I don't know whether > this is related to the sequence syntax or not > > sage: for n in [0.0,0.1,..,1.1]: > sage: print n, floor(n) > 0.000 0 > 0.100 0 > 0.200 0 > 0.300 0 > 0.400 0 > 0.500 0 > 0.600 0 > 0.700 0 > 0.800 0 > 0.900 0 > 1.00 0 <- What's going on here? > 1.10 1 > > I realise that the numbers are floating point and so on, but something > appears to have gone awry here in a big way > > On Apr 1, 7:13 pm, Mike Hansen wrote: > > > On Fri, Apr 1, 2011 at 8:08 PM, ObsessiveMathsFreak > > > wrote: > > >> sage: [0,0.2,..,1] > > >> [0.000, 0.200, 0.400, > > >> 0.600, 0.800, 1.00] > > > > May sage installation appears to be having trouble with this syntax > > > > OK Here > > > sage: [0.0,0.2,..,0.9] > > > [0.000, 0.200, 0.400, > > > 0.600, 0.800] > > > > But what's going on here? > > > sage: [0.1,0.2,..,0.9] > > > [0.100, 0.200, 0.300, > > > 0.400, 0.500, 0.600, > > > 0.700, 0.800, 0.900] > > > The second number (0.2) is not the amount to be incremented each time, > > it's the next number in the sequence. Since, 0.2 differs from 0.1 by > > 0.1, each additional number in the sequence will be incremented by > > 0.1. > > > > Something's gone dreadfully wrong. > > > sage: [0.2,0.2,..,0.9] > > > OverflowError: cannot convert float infinity to integer > > > There's no difference between 0.2 and 0.2, so it will never make it to 0.9. > > > > Now I'm just confused. > > > sage: [0.2,0.1,..,0.9] > > > [] > > > Going down from 0.2 to 0.1 and so on, you'll never reach 0.9. > > > --Mike > > -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] ring from operation tables
Given tables defining the addition and multiplication operations for a finite ring, is there a way to construct such a Ring() in Sage? For example: add_tab = Matrix([ [0, 1, 2, 3], [1, 0, 3, 2], [2, 3, 0, 1], [3, 2, 1, 0], ]) mul_tab = Matrix([ [0, 0, 0, 0], [0, 0, 0, 0], [0, 0, 1, 1], [0, 0, 1, 1], ]) -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Saving/Showing large animation consumes vast resources
I was having a problem with sage when trying to animate large images with many frames. Essentially, when the image was either being shown or saved to a gif file, the Imagemagick convert process would consumes gigabytes of memory, go out to swap, and the whole system would grind to a halt. I managed to solve this problem, as Imagemagick has done this to me before. The fix involves changing the command in the animate.py file where imagemagick is called. The convert command line needs to be changed from cmd = 'cd "%s"; sage-native-execute convert -delay %s -loop %s *.png "%s"'%(d, int(delay), int(iterations), savefile) to something like the following cmd = 'cd "%s"; sage-native-execute convert -limit memory 64mb -limit map 64mb -limit area 64mb -limit disk 128mb -delay %s -loop %s *.png "%s"'%(d, int(delay), int(iterations), savefile) Note the inclusion of resource usage limit commands. The numbers here I have essentially plucked from mid air. They work for me, but obviously need more looking into. I hope this is of use to anyone who may be having the same problem with showing and saving large animations. -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: Arithmetic Progession syntax
On 4/1/11 2:17 PM, ObsessiveMathsFreak wrote: Thanks for that, but I've run into another issue. I don't know whether this is related to the sequence syntax or not sage: for n in [0.0,0.1,..,1.1]: sage: print n, floor(n) 0.000 0 0.100 0 0.200 0 0.300 0 0.400 0 0.500 0 0.600 0 0.700 0 0.800 0 0.900 0 1.00 0<- What's going on here? 1.10 1 I realise that the numbers are floating point and so on, but something appears to have gone awry here in a big way You've answered your own question here: sage: a=[0.0,0.1,..,1.1] sage: a[-2] 1.00 sage: a[-2]==1 False sage: a[-2]-1 -1.11022302462516e-16 sage: a[-2]<1 True sage: b=a[-2] sage: b.str(truncate=False) # don't round '0.99989' If you want exact values and don't want to deal with messy floating point issues, then you can use exact values: sage: a=[0,1/10,..,11/10] sage: a [0, 1/10, 1/5, 3/10, 2/5, 1/2, 3/5, 7/10, 4/5, 9/10, 1, 11/10] sage: a[-2]==1 True Jason -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: Arithmetic Progession syntax
Thanks for that, but I've run into another issue. I don't know whether this is related to the sequence syntax or not sage: for n in [0.0,0.1,..,1.1]: sage: print n, floor(n) 0.000 0 0.100 0 0.200 0 0.300 0 0.400 0 0.500 0 0.600 0 0.700 0 0.800 0 0.900 0 1.00 0<- What's going on here? 1.10 1 I realise that the numbers are floating point and so on, but something appears to have gone awry here in a big way On Apr 1, 7:13 pm, Mike Hansen wrote: > On Fri, Apr 1, 2011 at 8:08 PM, ObsessiveMathsFreak > > > > wrote: > >> sage: [0,0.2,..,1] > >> [0.000, 0.200, 0.400, > >> 0.600, 0.800, 1.00] > > > May sage installation appears to be having trouble with this syntax > > > OK Here > > sage: [0.0,0.2,..,0.9] > > [0.000, 0.200, 0.400, > > 0.600, 0.800] > > > But what's going on here? > > sage: [0.1,0.2,..,0.9] > > [0.100, 0.200, 0.300, > > 0.400, 0.500, 0.600, > > 0.700, 0.800, 0.900] > > The second number (0.2) is not the amount to be incremented each time, > it's the next number in the sequence. Since, 0.2 differs from 0.1 by > 0.1, each additional number in the sequence will be incremented by > 0.1. > > > Something's gone dreadfully wrong. > > sage: [0.2,0.2,..,0.9] > > OverflowError: cannot convert float infinity to integer > > There's no difference between 0.2 and 0.2, so it will never make it to 0.9. > > > Now I'm just confused. > > sage: [0.2,0.1,..,0.9] > > [] > > Going down from 0.2 to 0.1 and so on, you'll never reach 0.9. > > --Mike -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] Re: Arithmetic Progession syntax
On Fri, Apr 1, 2011 at 8:08 PM, ObsessiveMathsFreak wrote: >> sage: [0,0.2,..,1] >> [0.000, 0.200, 0.400, >> 0.600, 0.800, 1.00] > > May sage installation appears to be having trouble with this syntax > > OK Here > sage: [0.0,0.2,..,0.9] > [0.000, 0.200, 0.400, > 0.600, 0.800] > > > But what's going on here? > sage: [0.1,0.2,..,0.9] > [0.100, 0.200, 0.300, > 0.400, 0.500, 0.600, > 0.700, 0.800, 0.900] The second number (0.2) is not the amount to be incremented each time, it's the next number in the sequence. Since, 0.2 differs from 0.1 by 0.1, each additional number in the sequence will be incremented by 0.1. > Something's gone dreadfully wrong. > sage: [0.2,0.2,..,0.9] > OverflowError: cannot convert float infinity to integer There's no difference between 0.2 and 0.2, so it will never make it to 0.9. > Now I'm just confused. > sage: [0.2,0.1,..,0.9] > [] Going down from 0.2 to 0.1 and so on, you'll never reach 0.9. --Mike -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: Arithmetic Progession syntax
> sage: [0,0.2,..,1] > [0.000, 0.200, 0.400, > 0.600, 0.800, 1.00] May sage installation appears to be having trouble with this syntax OK Here sage: [0.0,0.2,..,0.9] [0.000, 0.200, 0.400, 0.600, 0.800] But what's going on here? sage: [0.1,0.2,..,0.9] [0.100, 0.200, 0.300, 0.400, 0.500, 0.600, 0.700, 0.800, 0.900] Something's gone dreadfully wrong. sage: [0.2,0.2,..,0.9] OverflowError: cannot convert float infinity to integer Now I'm just confused. sage: [0.2,0.1,..,0.9] [] -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] sagenb.org
Is sagenb.org having problems? I tried to log on yesterday (and today, just now), and it said that my username was unknown! Victor -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
Re: [sage-support] commenting out
> In Python one can comment out a whole block of text with Alt+3, how > can I do that in Sage ? See this page: http://www.sagemath.org/doc/reference/sagenb/notebook/config.html /Håkan -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] commenting out
Hi all, In Python one can comment out a whole block of text with Alt+3, how can I do that in Sage ? TIA. Claude -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
[sage-support] Re: date call
Thank you all, very useful. Claude On Mar 31, 4:08 pm, Dan Drake wrote: > On Thu, 31 Mar 2011 at 05:36AM -0700, clodemil wrote: > > Is it possible to call up the calendar date and time, to be used in, > > for instance, m=list(measurement,date) ? > > Python (and hence Sage) has a number of modules related to times and > dates. Seehttp://docs.python.org/library/and search for "time" or > "date". > > Dan > > -- > --- Dan Drake > - http://mathsci.kaist.ac.kr/~drake > --- > > signature.asc > < 1KViewDownload -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
