fromfile error on windows, not mac
Hello,
I am using the numpy fromfile function to read binary data from a file
on disk. The problem is that the program runs fine on a Mac, but gives
an error or warning on windows when trying to read the data. I use it
like this:
Signal = zeros((N, 16), dtype=float32)
for sample in range(0, N):
# this function gets the next position in the file to seek to
s = getFilePos(sample)
# go to the correct location in the file; this IS checked to make
sure it is within the file
mFile.seek(s)
# read the 16 float32 values from the file
D = fromfile(mFile, dtype=numpy.float32, 16)
# save D in Signal
Signal[sample, :] = D
This will fail when sample is ~4. If I change the range to (5,N),
skipping the "bad" file location, it will run fine for a few samples,
and then give another error. The message it gives is:
"16 items requested but only 7 read"
So D is a 7x1 vector, and the program dies when it tries to assign D
to the slice of Signal ("ValueError: shape mismatch: objects cannot be
broadcast to a single shape").
On windows, the Python version is 2.5.2, and the most recent numpy and
scipy are being used as well. I tried using Enthought, but it gave
this error as well, in addition to a c runtime error whenever I
imported scipy (which is another post topic...).
Any ideas on what might be causing this? Is there a way to debug the
fromfile function? And, remember, this works perfectly on a Mac. Would
compiling everything (python, scipy, numpy) potentially solve this?
Thanks!
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Re: fromfile error on windows, not mac
On Jul 22, 2:05 am, Uwe Schmitt <[EMAIL PROTECTED]>
wrote:
> jadamwil schrieb:
>
>
>
> > Hello,
> > I am using the numpy fromfile function to read binary data from a file
> > on disk. The problem is that the program runs fine on a Mac, but gives
> > an error or warning on windows when trying to read the data. I use it
> > like this:
>
> > Signal = zeros((N, 16), dtype=float32)
> > for sample in range(0, N):
> > # this function gets the next position in the file to seek to
> > s = getFilePos(sample)
>
> > # go to the correct location in the file; this IS checked to make
> > sure it is within the file
> > mFile.seek(s)
>
> > # read the 16 float32 values from the file
> > D = fromfile(mFile, dtype=numpy.float32, 16)
>
> > # save D in Signal
> > Signal[sample, :] = D
>
> > This will fail when sample is ~4. If I change the range to (5,N),
> > skipping the "bad" file location, it will run fine for a few samples,
> > and then give another error. The message it gives is:
> > "16 items requested but only 7 read"
>
> > So D is a 7x1 vector, and the program dies when it tries to assign D
> > to the slice of Signal ("ValueError: shape mismatch: objects cannot be
> > broadcast to a single shape").
>
> > On windows, the Python version is 2.5.2, and the most recent numpy and
> > scipy are being used as well. I tried using Enthought, but it gave
> > this error as well, in addition to a c runtime error whenever I
> > imported scipy (which is another post topic...).
>
> > Any ideas on what might be causing this? Is there a way to debug the
> > fromfile function? And, remember, this works perfectly on a Mac. Would
> > compiling everything (python, scipy, numpy) potentially solve this?
>
> Did you open the file in binary mode ?
>
> Greetings, Uwe
Yes I did. Would that make a difference between a mac and windows?
Thanks
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Re: fromfile error on windows, not mac
On Jul 22, 8:35 am, jadamwil <[EMAIL PROTECTED]> wrote:
> On Jul 22, 2:05 am, Uwe Schmitt <[EMAIL PROTECTED]>
> wrote:
>
>
>
> > jadamwil schrieb:
>
> > > Hello,
> > > I am using the numpy fromfile function to read binary data from a file
> > > on disk. The problem is that the program runs fine on a Mac, but gives
> > > an error or warning onwindowswhen trying to read the data. I use it
> > > like this:
>
> > > Signal = zeros((N, 16), dtype=float32)
> > > for sample in range(0, N):
> > > # this function gets the next position in the file to seek to
> > > s = getFilePos(sample)
>
> > > # go to the correct location in the file; this IS checked to make
> > > sure it is within the file
> > > mFile.seek(s)
>
> > > # read the 16 float32 values from the file
> > > D = fromfile(mFile, dtype=numpy.float32, 16)
>
> > > # save D in Signal
> > > Signal[sample, :] = D
>
> > > This will fail when sample is ~4. If I change the range to (5,N),
> > > skipping the "bad" file location, it will run fine for a few samples,
> > > and then give another error. The message it gives is:
> > > "16 items requested but only 7 read"
>
> > > So D is a 7x1 vector, and the program dies when it tries to assign D
> > > to the slice of Signal ("ValueError: shape mismatch: objects cannot be
> > > broadcast to a single shape").
>
> > > Onwindows, the Python version is 2.5.2, and the most recent numpy and
> > > scipy are being used as well. I tried using Enthought, but it gave
> > > this error as well, in addition to a c runtime error whenever I
> > > imported scipy (which is another post topic...).
>
> > > Any ideas on what might be causing this? Is there a way to debug the
> > > fromfile function? And, remember, this works perfectly on a Mac. Would
> > > compiling everything (python, scipy, numpy) potentially solve this?
>
> > Did you open the file in binary mode ?
>
> > Greetings, Uwe
>
> Yes I did. Would that make a difference between a mac andwindows?
> Thanks
Uwe,
Thanks for the suggestion. I passed "rb" to the open file command, not
'rb' which made a difference. I thought it opened in binary, but it
did not, and it seems windows is not as good unix for dealing with
this situation.
Adam
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Re: fromfile error on windows, not mac
I found the problem: I thought it was opening in binary mode on BOTH
windows and the mac, but on windows I passed "rb" with double quotes,
not 'rb' with single quotes to the open file function. Changing it to
'rb' fixed it.
On Jul 23, 8:25 am, Tommy Nordgren <[EMAIL PROTECTED]> wrote:
> One question : Did you remember to open the file in binary mode?
> This MUST be done on windows.
> On 22 jul 2008, at 06.36, jadamwil wrote:
>
>
>
> > Hello,
> > I am using the numpy fromfile function to read binary data from a file
> > on disk. The problem is that the program runs fine on a Mac, but gives
> > an error or warning on windows when trying to read the data. I use it
> > like this:
>
> > Signal = zeros((N, 16), dtype=float32)
> > for sample in range(0, N):
> > # this function gets the next position in the file to seek to
> > s = getFilePos(sample)
>
> > # go to the correct location in the file; this IS checked to make
> > sure it is within the file
> > mFile.seek(s)
>
> > # read the 16 float32 values from the file
> > D = fromfile(mFile, dtype=numpy.float32, 16)
>
> > # save D in Signal
> > Signal[sample, :] = D
>
> > This will fail when sample is ~4. If I change the range to (5,N),
> > skipping the "bad" file location, it will run fine for a few samples,
> > and then give another error. The message it gives is:
> > "16 items requested but only 7 read"
>
> > So D is a 7x1 vector, and the program dies when it tries to assign D
> > to the slice of Signal ("ValueError: shape mismatch: objects cannot be
> > broadcast to a single shape").
>
> > On windows, the Python version is 2.5.2, and the most recent numpy and
> > scipy are being used as well. I tried using Enthought, but it gave
> > this error as well, in addition to a c runtime error whenever I
> > imported scipy (which is another post topic...).
>
> > Any ideas on what might be causing this? Is there a way to debug the
> > fromfile function? And, remember, this works perfectly on a Mac. Would
> > compiling everything (python, scipy, numpy) potentially solve this?
>
> > Thanks!
> > --
> >http://mail.python.org/mailman/listinfo/python-list
>
> --
> Skinheads are so tired of immigration, that they are going to move to
> a country that don't accept immigrants!
> Tommy Nordgren
> [EMAIL PROTECTED]
--
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Re: fromfile error on windows, not mac
On Jul 23, 3:30 pm, Fredrik Lundh <[EMAIL PROTECTED]> wrote: > Manu Hack wrote: > > by the way, anyone could explain why changing to single quote makes a > > difference? > > > >>> "rb" == 'rb' > > True > > There's no difference between single quotes and double quotes in Python. > My guess is cargo cult debugging. > > Ha...you're probably not that far from the truth. I just started with python about a week ago, and have had a LOT of luck getting our lab's data analysis routines ported from matlab, with the exception of this problem. I tried a lot of different things to get it working on windows, and I think I got python quotes confused with matlab or php quotes (where double and single quotes are different), tried it, and it happened to work (although I probably changed something else as well in desperation). Of course, as many have pointed out, this does not actually matter in python. So anyway, yes, someone new to a language trying lots of different things without a full understanding of the language could probably be considered cargo cult programming :-). Thanks for the replies though! -- http://mail.python.org/mailman/listinfo/python-list
