Re: [Numpy-discussion] float96 on windows32 is float64?
I just did a quick test across all supported EPD platforms: win-64: float96 No, float128 No win-32: float96 No, float128 No osx-64: float96 No, float128 Yes osx-32: float96 No, float128 Yes rh3-64: float96 No, float128 Yes rh3-32: float96 Yes, float128 No rh5-64: float96 No, float128 Yes rh5-32: float96 Yes, float128 No sol-64: float96 No, float128 Yes sol-32: float96 Yes, float128 No I have no explanation for this, but I'm guessing David C. has. I'll look more into this tomorrow. - Ilan On Fri, Mar 16, 2012 at 12:40 AM, Matthew Brett matthew.br...@gmail.com wrote: Hi, On Thu, Mar 15, 2012 at 10:26 PM, Ilan Schnell ischn...@enthought.com wrote: To be more precise. On both 32-bit and 64-bit Windows machines I don't see.float96 as well as np.float128 Do you have any idea why I am seeing float96 and you are not? I'm on XP with the current sourceforge 1.6.1 exe installer with python.org 2.7 (and same for python.org 2.6 and numpy 1.5.1). Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
On Fri, Mar 16, 2012 at 2:10 AM, Ilan Schnell ischn...@enthought.com wrote: I just did a quick test across all supported EPD platforms: win-64: float96 No, float128 No win-32: float96 No, float128 No osx-64: float96 No, float128 Yes osx-32: float96 No, float128 Yes rh3-64: float96 No, float128 Yes rh3-32: float96 Yes, float128 No rh5-64: float96 No, float128 Yes rh5-32: float96 Yes, float128 No sol-64: float96 No, float128 Yes sol-32: float96 Yes, float128 No numpy 1.5.1 MingW, on python 2.6 win32 has float96, float128 no numpy 1.6.1 Gohlke (MKL I think) on python 3.2 win64 no float96, no float128 Josef I have no explanation for this, but I'm guessing David C. has. I'll look more into this tomorrow. - Ilan On Fri, Mar 16, 2012 at 12:40 AM, Matthew Brett matthew.br...@gmail.com wrote: Hi, On Thu, Mar 15, 2012 at 10:26 PM, Ilan Schnell ischn...@enthought.com wrote: To be more precise. On both 32-bit and 64-bit Windows machines I don't see.float96 as well as np.float128 Do you have any idea why I am seeing float96 and you are not? I'm on XP with the current sourceforge 1.6.1 exe installer with python.org 2.7 (and same for python.org 2.6 and numpy 1.5.1). Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
Hi, On Fri, Mar 16, 2012 at 5:36 AM, josef.p...@gmail.com wrote: On Fri, Mar 16, 2012 at 2:10 AM, Ilan Schnell ischn...@enthought.com wrote: I just did a quick test across all supported EPD platforms: win-64: float96 No, float128 No win-32: float96 No, float128 No osx-64: float96 No, float128 Yes osx-32: float96 No, float128 Yes rh3-64: float96 No, float128 Yes rh3-32: float96 Yes, float128 No rh5-64: float96 No, float128 Yes rh5-32: float96 Yes, float128 No sol-64: float96 No, float128 Yes sol-32: float96 Yes, float128 No numpy 1.5.1 MingW, on python 2.6 win32 has float96, float128 no numpy 1.6.1 Gohlke (MKL I think) on python 3.2 win64 no float96, no float128 Josef I have no explanation for this, but I'm guessing David C. has. I'll look more into this tomorrow. - Ilan Oh dear - I completely forgot the previous thread that I started on this : http://mail.scipy.org/pipermail/numpy-discussion/2011-November/059233.html You young people, don't laugh, this will happen to you one day. Anyway, summarizing, it appears that windows float96: a) Is stored as an 80 bit extended precision number b) Uses float64 precision for all calculations. c) Is specific to MingW builds of numpy - I think. Perhaps David C you'll correct me if I've got that wrong, Best, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
[Numpy-discussion] float96 on windows32 is float64?
Hi, Am I right in thinking that float96 on windows 32 bit is a float64 padded to 96 bits? If so, is it useful? Has anyone got a windows64 box to check float128 ? Python 2.7.1 (r271:86832, Nov 27 2010, 18:30:46) [MSC v.1500 32 bit (Intel)] on win32 Type help, copyright, credits or license for more information. import numpy as np np.__version__ '1.6.1' info = np.finfo(np.float96) print info Machine parameters for float96 - precision= 15 resolution= 1e-15 machep= -52 eps=2.22044604925e-16 negep = -53 epsneg= 1.11022302463e-16 minexp=-16382 tiny= 0.0 maxexp= 16384 max=1.#INF nexp =15 min=-max - info.nmant 52 Confirming 52 (+1 implicit) significand digits np.float96(2**52)+1 4503599627370497.0 np.float96(2**53)+1 9007199254740992.0 float96 claims 15 exponent digits (nexp above), but in fact it appears to have 11, as does float64 np.float64(2**1022) * 2 8.9884656743115795e+307 np.float64(2**1022) * 4 __main__:1: RuntimeWarning: overflow encountered in double_scalars inf np.float96(2**1022) * 2 8.9884656743115795e+307 np.float96(2**1022) * 4 1.#INF It does take up 12 bytes (96 bits) np.dtype(np.float96).itemsize 12 Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
On Thu, Mar 15, 2012 at 11:10 PM, Matthew Brett matthew.br...@gmail.comwrote: Hi, Am I right in thinking that float96 on windows 32 bit is a float64 padded to 96 bits? Yes If so, is it useful? Yes: this is what allows you to use dtype to parse complex binary files directly in numpy without having to care so much about those details. And that's how it is defined on windows in any case (C standard only forces you to have sizeof(long double) = sizeof(double)). Has anyone got a windows64 box to check float128 ? Too lazy to check on my vm, but I am pretty sure it is 16 bytes on windows 64. David ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
On Thu, Mar 15, 2012 at 10:17 PM, David Cournapeau courn...@gmail.comwrote: On Thu, Mar 15, 2012 at 11:10 PM, Matthew Brett matthew.br...@gmail.comwrote: Hi, Am I right in thinking that float96 on windows 32 bit is a float64 padded to 96 bits? Yes If so, is it useful? Yes: this is what allows you to use dtype to parse complex binary files directly in numpy without having to care so much about those details. And that's how it is defined on windows in any case (C standard only forces you to have sizeof(long double) = sizeof(double)). Has anyone got a windows64 box to check float128 ? Too lazy to check on my vm, but I am pretty sure it is 16 bytes on windows 64. Wait, MSVC doesn't support extended precision, so how do we get doubles padded to 96 bits? I think MINGW supports extended precision but the MS libraries won't. Still, if it's doubles it should be 64 bits and float96 shouldn't exist. Doubles padded to 96 bits are 150% pointless. Chuck ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
Hi, On Thu, Mar 15, 2012 at 9:17 PM, David Cournapeau courn...@gmail.com wrote: On Thu, Mar 15, 2012 at 11:10 PM, Matthew Brett matthew.br...@gmail.com wrote: Hi, Am I right in thinking that float96 on windows 32 bit is a float64 padded to 96 bits? Yes If so, is it useful? Yes: this is what allows you to use dtype to parse complex binary files directly in numpy without having to care so much about those details. And that's how it is defined on windows in any case (C standard only forces you to have sizeof(long double) = sizeof(double)). I propose then to rename this one to float64_96 . The nexp value in finfo(np.float96) is incorrect I believe, I'll make a ticket for it. Has anyone got a windows64 box to check float128 ? Too lazy to check on my vm, but I am pretty sure it is 16 bytes on windows 64. Should you have time to do that, could you confirm it's also a padded float64 and that nexp is still (incorrectly) 15? That would be a great help, Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
Hi, On Thu, Mar 15, 2012 at 9:24 PM, Charles R Harris charlesr.har...@gmail.com wrote: On Thu, Mar 15, 2012 at 10:17 PM, David Cournapeau courn...@gmail.com wrote: On Thu, Mar 15, 2012 at 11:10 PM, Matthew Brett matthew.br...@gmail.com wrote: Hi, Am I right in thinking that float96 on windows 32 bit is a float64 padded to 96 bits? Yes If so, is it useful? Yes: this is what allows you to use dtype to parse complex binary files directly in numpy without having to care so much about those details. And that's how it is defined on windows in any case (C standard only forces you to have sizeof(long double) = sizeof(double)). Has anyone got a windows64 box to check float128 ? Too lazy to check on my vm, but I am pretty sure it is 16 bytes on windows 64. Wait, MSVC doesn't support extended precision, so how do we get doubles padded to 96 bits? I think MINGW supports extended precision but the MS libraries won't. Still, if it's doubles it should be 64 bits and float96 shouldn't exist. Doubles padded to 96 bits are 150% pointless. I think David is arguing that longdouble for MSVC is indeed a 96 bit padded float64 unless I misunderstand him. If we were thinking of trade-offs I suppose one could argue that the confusion and wasted memory of float96 might outweigh the simple ability to read in binary files containing these values, on the basis that one can do it anyway (by using a structured array dtype) and that such files must be very rare in practice. See you, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
I just happened to have an xp64 VM running: My version of numpy (1.6.1) does not have float128 (see more below what I get in ipython session). If you need to test something else please let me know. Val --- Enthought Python Distribution -- www.enthought.com Python 2.7.2 |EPD 7.2-2 (64-bit)| (default, Jul 3 2011, 15:34:33) [MSC v.1500 6 4 bit (AMD64)] Type copyright, credits or license for more information. IPython 0.12 -- An enhanced Interactive Python. ? - Introduction and overview of IPython's features. %quickref - Quick reference. help - Python's own help system. object? - Details about 'object', use 'object??' for extra details. Welcome to pylab, a matplotlib-based Python environment [backend: WXAgg]. For more information, type 'help(pylab)'. In [1]: import numpy as np In [2]: np.__version__ Out[2]: '1.6.1' In [3]: np.flo np.floatnp.float32 np.float_ np.floor np.float16 np.float64 np.floating np.floor_divide In [3]: np.flo On Thu, Mar 15, 2012 at 11:25 PM, Matthew Brett matthew.br...@gmail.comwrote: Hi, On Thu, Mar 15, 2012 at 9:17 PM, David Cournapeau courn...@gmail.com wrote: On Thu, Mar 15, 2012 at 11:10 PM, Matthew Brett matthew.br...@gmail.com wrote: Hi, Am I right in thinking that float96 on windows 32 bit is a float64 padded to 96 bits? Yes If so, is it useful? Yes: this is what allows you to use dtype to parse complex binary files directly in numpy without having to care so much about those details. And that's how it is defined on windows in any case (C standard only forces you to have sizeof(long double) = sizeof(double)). I propose then to rename this one to float64_96 . The nexp value in finfo(np.float96) is incorrect I believe, I'll make a ticket for it. Has anyone got a windows64 box to check float128 ? Too lazy to check on my vm, but I am pretty sure it is 16 bytes on windows 64. Should you have time to do that, could you confirm it's also a padded float64 and that nexp is still (incorrectly) 15? That would be a great help, Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
On Thursday, March 15, 2012, Charles R Harris charlesr.har...@gmail.com wrote: On Thu, Mar 15, 2012 at 10:17 PM, David Cournapeau courn...@gmail.com wrote: On Thu, Mar 15, 2012 at 11:10 PM, Matthew Brett matthew.br...@gmail.com wrote: Hi, Am I right in thinking that float96 on windows 32 bit is a float64 padded to 96 bits? Yes If so, is it useful? Yes: this is what allows you to use dtype to parse complex binary files directly in numpy without having to care so much about those details. And that's how it is defined on windows in any case (C standard only forces you to have sizeof(long double) = sizeof(double)). Has anyone got a windows64 box to check float128 ? Too lazy to check on my vm, but I am pretty sure it is 16 bytes on windows 64. Wait, MSVC doesn't support extended precision, so how do we get doubles padded to 96 bits? I think MINGW supports extended precision but the MS libraries won't. Still, if it's doubles it should be 64 bits and float96 shouldn't exist. Doubles padded to 96 bits are 150% pointless. Chuck There is a Microsoft joke in there, somewhere... Ben Root ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
Hi, On Thu, Mar 15, 2012 at 9:33 PM, Val Kalatsky kalat...@gmail.com wrote: I just happened to have an xp64 VM running: My version of numpy (1.6.1) does not have float128 (see more below what I get in ipython session). If you need to test something else please let me know. Thanks a lot - that's helpful. What do you get for: print np.finfo(np.longdouble) ? Best, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
I does look like a joke. Here is print np.finfo(np.longdouble) In [2]: np.__version__ Out[2]: '1.6.1' In [3]: np.flo np.floatnp.float32 np.float_ np.floor np.float16 np.float64 np.floating np.floor_divide In [3]: print np.finfo(np.longdouble) Machine parameters for float64 - precision= 15 resolution= 1e-15 machep= -52 eps=2.22044604925e-16 negep = -53 epsneg= 1.11022302463e-16 minexp= -1022 tiny= 2.22507385851e-308 maxexp= 1024 max=1.79769313486e+308 nexp =11 min=-max - On Thu, Mar 15, 2012 at 11:38 PM, Matthew Brett matthew.br...@gmail.comwrote: Hi, On Thu, Mar 15, 2012 at 9:33 PM, Val Kalatsky kalat...@gmail.com wrote: I just happened to have an xp64 VM running: My version of numpy (1.6.1) does not have float128 (see more below what I get in ipython session). If you need to test something else please let me know. Thanks a lot - that's helpful. What do you get for: print np.finfo(np.longdouble) ? Best, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
On Thu, Mar 15, 2012 at 11:41 PM, Val Kalatsky kalat...@gmail.com wrote: I does look like a joke. Here is print np.finfo(np.longdouble) In [2]: np.__version__ Out[2]: '1.6.1' In [3]: np.flo np.floatnp.float32 np.float_ np.floor np.float16 np.float64 np.floating np.floor_divide In [3]: print np.finfo(np.longdouble) Machine parameters for float64 - precision= 15 resolution= 1e-15 machep= -52 eps=2.22044604925e-16 negep = -53 epsneg= 1.11022302463e-16 minexp= -1022 tiny= 2.22507385851e-308 maxexp= 1024 max=1.79769313486e+308 nexp =11 min=-max - In this case (Win64), np.longdouble is just an alias for np.float64: In [16]: sys.version Out[16]: '2.7.2 |EPD 7.2-2 (64-bit)| (default, Sep 14 2011, 11:25:00) [MSC v.1500 64 bit (AMD64)]' In [17]: np.__version__ Out[17]: '1.6.1' In [18]: np.longdouble Out[18]: numpy.float64 Warren On Thu, Mar 15, 2012 at 11:38 PM, Matthew Brett matthew.br...@gmail.comwrote: Hi, On Thu, Mar 15, 2012 at 9:33 PM, Val Kalatsky kalat...@gmail.com wrote: I just happened to have an xp64 VM running: My version of numpy (1.6.1) does not have float128 (see more below what I get in ipython session). If you need to test something else please let me know. Thanks a lot - that's helpful. What do you get for: print np.finfo(np.longdouble) ? Best, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
Hi, On Thu, Mar 15, 2012 at 9:41 PM, Val Kalatsky kalat...@gmail.com wrote: I does look like a joke. Here is print np.finfo(np.longdouble) In [2]: np.__version__ Out[2]: '1.6.1' In [3]: np.flo np.float np.float32 np.float_ np.floor np.float16 np.float64 np.floating np.floor_divide In [3]: print np.finfo(np.longdouble) Machine parameters for float64 - precision= 15 resolution= 1e-15 machep= -52 eps= 2.22044604925e-16 negep = -53 epsneg= 1.11022302463e-16 minexp= -1022 tiny= 2.22507385851e-308 maxexp= 1024 max= 1.79769313486e+308 nexp = 11 min= -max - Great - much easier on the eye - longdouble is float64 as expected. Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
I'm seeing the same thing on both (64 and 32-bit) Windows EPD test machines. I guess Windows does not support 128 bit floats. I did some tests a few weeks ago, and discovered that also on the Mac and Linux long long double is not really 128 bits. If I remember correctly it was 80 bits: 1 (sign) + 16 (exp) + 63 (mantissa) - Ilan On Thu, Mar 15, 2012 at 11:52 PM, Matthew Brett matthew.br...@gmail.com wrote: Hi, On Thu, Mar 15, 2012 at 9:41 PM, Val Kalatsky kalat...@gmail.com wrote: I does look like a joke. Here is print np.finfo(np.longdouble) In [2]: np.__version__ Out[2]: '1.6.1' In [3]: np.flo np.float np.float32 np.float_ np.floor np.float16 np.float64 np.floating np.floor_divide In [3]: print np.finfo(np.longdouble) Machine parameters for float64 - precision= 15 resolution= 1e-15 machep= -52 eps= 2.22044604925e-16 negep = -53 epsneg= 1.11022302463e-16 minexp= -1022 tiny= 2.22507385851e-308 maxexp= 1024 max= 1.79769313486e+308 nexp = 11 min= -max - Great - much easier on the eye - longdouble is float64 as expected. Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
Hi, On Thu, Mar 15, 2012 at 10:17 PM, Ilan Schnell ischn...@enthought.com wrote: I'm seeing the same thing on both (64 and 32-bit) Windows EPD test machines. I guess Windows does not support 128 bit floats. Do you mean there is no float96 on windows 32 bit as I described at the beginning of the thread? I did some tests a few weeks ago, and discovered that also on the Mac and Linux long long double is not really 128 bits. If I remember correctly it was 80 bits: 1 (sign) + 16 (exp) + 63 (mantissa) Yes, that's right, on Intel for linux and OSX longdouble is 80 bit precision. Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
To be more precise. On both 32-bit and 64-bit Windows machines I don't see.float96 as well as np.float128 - Ilan On Fri, Mar 16, 2012 at 12:22 AM, Matthew Brett matthew.br...@gmail.com wrote: Hi, On Thu, Mar 15, 2012 at 10:17 PM, Ilan Schnell ischn...@enthought.com wrote: I'm seeing the same thing on both (64 and 32-bit) Windows EPD test machines. I guess Windows does not support 128 bit floats. Do you mean there is no float96 on windows 32 bit as I described at the beginning of the thread? I did some tests a few weeks ago, and discovered that also on the Mac and Linux long long double is not really 128 bits. If I remember correctly it was 80 bits: 1 (sign) + 16 (exp) + 63 (mantissa) Yes, that's right, on Intel for linux and OSX longdouble is 80 bit precision. Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
Re: [Numpy-discussion] float96 on windows32 is float64?
Hi, On Thu, Mar 15, 2012 at 10:26 PM, Ilan Schnell ischn...@enthought.com wrote: To be more precise. On both 32-bit and 64-bit Windows machines I don't see.float96 as well as np.float128 Do you have any idea why I am seeing float96 and you are not? I'm on XP with the current sourceforge 1.6.1 exe installer with python.org 2.7 (and same for python.org 2.6 and numpy 1.5.1). Thanks, Matthew ___ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
