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<DIV><FONT face=Calibri>Hi Hom Nath,</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>Thank you very much for your email. The code you send it
starting to make sense for me, I would just appreciate if you would explain a
few things for me. At the minute I am outputting as follows within
<AppendedData>:</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>size = idim*jdim*sizeof(float);</FONT></DIV>
<DIV><FONT face=Calibri>totalsize = size*4;</FONT></DIV>
<DIV><FONT face=Calibri>file << "_";</FONT></DIV>
<DIV><FONT face=Calibri>file.write(reinterpret_case<const
char*>(&totalsize), 4);</FONT></DIV>
<DIV><FONT face=Calibri>file.write(&Array1, size);</FONT></DIV>
<DIV><FONT face=Calibri>file.write(&Array2, size);</FONT></DIV>
<DIV><FONT face=Calibri>file.write(&Array3, size);</FONT></DIV>
<DIV><FONT face=Calibri>file.write(&Array4, size);</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>But sadly it's not working. I compute the offset
as:</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>for (i = 0; i < 4; i++)</FONT></DIV>
<DIV><FONT face=Calibri>{</FONT></DIV>
<DIV> <FONT face=Calibri>offset[i] = i*size;</FONT></DIV>
<DIV><FONT face=Calibri>}</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>Things get extremely strange in Paraview. I have one
outputting five arrays same as above and I can read and view for first, third
and fifth no problems but not the second or the fourth. The three that read even
look like they should (although without extremely detailed
checking.</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>I assume I am missing something about how to either
compute the offset or the binary layout. Your code seems to say that each
dataarray should have its own integer binary output tells the size of that data
instead of just one at the start of the array?</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>Any help is greatly appreciated.</FONT></DIV>
<DIV><FONT face=Calibri>David</FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV style="FONT: 10pt Tahoma">
<DIV><FONT size=3 face=Calibri></FONT><BR></DIV>
<DIV style="BACKGROUND: #f5f5f5">
<DIV style="font-color: black"><B>From:</B> <A title=hng.email@gmail.com
href="mailto:hng.email@gmail.com">Hom Nath Gharti</A> </DIV>
<DIV><B>Sent:</B> Wednesday, April 01, 2009 1:59 PM</DIV>
<DIV><B>To:</B> <A title=d.t.mulholland@googlemail.com
href="mailto:d.t.mulholland@googlemail.com">David Mulholland</A> </DIV>
<DIV><B>Cc:</B> <A title=th@tp1.rub.de href="mailto:th@tp1.rub.de">Thorsten
Hater</A> ; <A title=paraview@paraview.org
href="mailto:paraview@paraview.org">paraview@paraview.org</A> </DIV>
<DIV><B>Subject:</B> Re: [Paraview] VTK XML Binary Output</DIV></DIV></DIV>
<DIV><BR></DIV>I thought my C code may be helpful to you. I have 5 data array of
different size, and I do like this:<BR><BR>nvar=5;<BR>/* Bytes and offsets for
ParaView file */ <BR> bytes[0] =
(ndim*nnod)*sizeof(float); /* Coordinates
*/<BR> bytes[1] = (nenod*nelmt)*sizeof(int);
/* Connectivity */<BR> bytes[2] =
(nelmt)*sizeof(int); /* Offsets
*/<BR> bytes[3] = (nelmt)*sizeof(int);
/* Types */<BR> bytes[4] =
(nelmt)*sizeof(float); /* Cell data
*/<BR> <BR> off[0]=0; /* 1st offset
*/<BR> for (i=0; i<nvar; i++){
<BR>
if(i<nvar-1)off[i+1]=off[i]+sizeof(int)+bytes[i];<BR>
bytes[i]=bytes[i]+sizeof(int); /* For each byte we must also
add the sizeof(int) for itself also */ <BR>
}<BR><BR>Best wishes,<BR>Hom Nath<BR><BR>
<DIV class=gmail_quote>2009/4/1 David Mulholland <SPAN dir=ltr><<A
href="mailto:d.t.mulholland@googlemail.com">d.t.mulholland@googlemail.com</A>></SPAN><BR>
<BLOCKQUOTE
style="BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0pt 0pt 0pt 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote>
<DIV style="PADDING-LEFT: 10px; PADDING-RIGHT: 10px; PADDING-TOP: 15px"
name="Compose message area" bgcolor="#ffffff" text="#000000">
<DIV><FONT face=Calibri>Hi Thorsten, </FONT></DIV>
<DIV><FONT face=Calibri></FONT> </DIV>
<DIV><FONT face=Calibri>I just tried that and it is now giving me a
segmentation fault... I am using the following line: </FONT></DIV>
<DIV><FONT size=2>file.write(</FONT><FONT color=#40ffff size=2><FONT
color=#40ffff size=2>reinterpret_cast</FONT></FONT><FONT
size=2><</FONT><FONT color=#40ffff size=2><FONT color=#40ffff
size=2>const</FONT></FONT><FONT size=2> </FONT><FONT color=#00bf00
size=2><FONT color=#00bf00 size=2>char</FONT></FONT><FONT size=2>*>(size),
4);</FONT></DIV>
<DIV
style="FONT: 10pt Tahoma; font-size-adjust: none; font-stretch: normal"><FONT
size=3 face=Calibri></FONT> </DIV>
<DIV style="FONT: 10pt Tahoma; font-size-adjust: none; font-stretch: normal">
<DIV><FONT size=3 face=Calibri>My size is calculated as - int size =
idim*jdim*sizeof(float). idim is currently in the region of 400 and jdim 200.
I am outputting big files and it is likely to get bigger.</FONT></DIV><FONT
size=3 face=Calibri></FONT></DIV>
<DIV
style="FONT: 10pt Tahoma; font-size-adjust: none; font-stretch: normal"><FONT
size=3 face=Calibri></FONT><FONT size=3 face=Calibri></FONT> </DIV>
<DIV
style="FONT: 10pt Tahoma; font-size-adjust: none; font-stretch: normal"><FONT
size=3 face=Calibri>Also, I intend to include more data arrays each timestep,
I just want to get it working with pressure first and then I will include then
which is why I want to calculate the offset... I assuming it is just the
number of bytes to the start of the next datafield...</FONT></DIV>
<DIV
style="FONT: 10pt Tahoma; font-size-adjust: none; font-stretch: normal"><FONT
size=3 face=Calibri></FONT> </DIV>
<DIV
style="FONT: 10pt Tahoma; font-size-adjust: none; font-stretch: normal"><FONT
size=3 face=Calibri>Thanks David</FONT>
<DIV><BR></DIV>
<DIV
style="BACKGROUND: rgb(245,245,245); -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial">
<DIV><B>From:</B> <A title=th@tp1.rub.de href="mailto:th@tp1.rub.de"
target=_blank>Thorsten Hater</A> </DIV>
<DIV><B>Sent:</B> Wednesday, April 01, 2009 10:55 AM</DIV>
<DIV>
<DIV></DIV>
<DIV class=h5>
<DIV><B>To:</B> <A title=d.t.mulholland@googlemail.com
href="mailto:d.t.mulholland@googlemail.com" target=_blank>David Mulholland</A>
</DIV>
<DIV><B>Cc:</B> <A title=paraview@paraview.org
href="mailto:paraview@paraview.org" target=_blank>paraview@paraview.org</A>
</DIV>
<DIV><B>Subject:</B> Re: [Paraview] VTK XML Binary
Output</DIV></DIV></DIV></DIV></DIV>
<DIV>
<DIV></DIV>
<DIV class=h5>
<DIV><BR></DIV>Hello David,<BR><BR>the offset parameter is relevant if you
append mulitple data sections into a single file.<BR>Every DataArray tag with
append format specifies the offset as the position in the <BR>binary data in
bytes.<BR>To write the integer I use the following:<BR><BR>std::ofstream os;
// binary mode (for windows ...) ofstream to your file<BR>int N; // size in
bytes<BR>os.write(reinterpret_cast<const char*>(N),
4);<BR><BR>Thorsten<BR><BR>David Mulholland schrieb:
<BLOCKQUOTE type="cite">
<DIV>Hi Thorsten,<BR><BR>That's really helpful. I don't quite know how to
write out the number of bits as a char? If you could explain a way of how to
do that it would be greatly appreciated. <BR><BR>Also, how do I calculate
what value goes in for the offset? I had a look at a couple of output files
from paraview and it wasnt obvious how it was
calculated.<BR><BR>Thanks<BR>David</DIV>
<DIV
style="FONT: 10pt Tahoma; font-size-adjust: none; font-stretch: normal">
<DIV><BR></DIV>
<DIV
style="BACKGROUND: rgb(245,245,245) 0% 50%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial">
<DIV><B>From:</B> <A title=th@tp1.rub.de href="mailto:th@tp1.rub.de"
target=_blank>Thorsten Hater</A> </DIV>
<DIV><B>Sent:</B> Tuesday, March 31, 2009 2:23 PM</DIV>
<DIV><B>To:</B> <A title=d.t.mulholland@googlemail.com
href="mailto:d.t.mulholland@googlemail.com" target=_blank>David
Mulholland</A> </DIV>
<DIV><B>Cc:</B> <A title=paraview@paraview.org
href="mailto:paraview@paraview.org" target=_blank>paraview@paraview.org</A>
</DIV>
<DIV><B>Subject:</B> Re: [Paraview] VTK XML Binary Output</DIV></DIV></DIV>
<DIV><BR></DIV>Hello,<BR><BR>the solution might be to append your data
as<BR><BR>< DataArray ...
format="appended"><BR></DataArray><BR>< AppendedData
encoding="raw"><BR>_NNNNData <BR></AppendedData><BR>where you
should replace NNNN with a four <BR>byte integer containing the number of
bytes <BR>in the data array as 4 chars.<BR>Setting the encoding to "raw"
tells ParaView, that<BR>the data is simply a stream of bytes rather than
<BR>base64 encoded.<BR>If you want to write Image I can supply a
small<BR>writer project for 2D data.<BR><BR>
Thorsten<BR> <BR>David Mulholland schrieb:
<BLOCKQUOTE type="cite">
<DIV>Hello,<BR><BR>I am currently trying to write my own quick output
routine to generate a <BR>binary file using C++. I am currently trying to
avoid having to use the vtk <BR>libraries because I only need a very basic
output that doesn't change much. <BR>I so far have the ASCII output
working no problem but I can't get the binary <BR>working.<BR><BR>I am
using file.write() function to output the binary data and that seems to
<BR>be working no problem and when used in a legacy format application it
works <BR>perfectly except that the data is LittleEndian instead of
BigEndian. That's <BR>why I have moved to BigEndian because I don't want
to have to make the <BR>output routine for the data anymore complicated
that file.write.<BR><BR>I started using the xml format and considering my
output is raw binary and <BR>not base64 I changed it to be in the
AppendedData section instead of <BR>DataArray. It still isn't working
right, I get the following error when I <BR>try to load in
ParaView:<BR><BR>ERROR: In
..\..\..\ParaView3\VTK\IO\vtkXMLStructuredDataReader.cxx, line
349<BR>vtkXMLImageDataReader (0ADEC7F8): Error reading extent 0 422 0 242
0 1 from <BR>piece 0<BR><BR><BR>ERROR: In
..\..\..\ParaView3\VTK\IO\vtkXMLDataReader.cxx, line
537<BR>vtkXMLImageDataReader (0ADEC7F8): Cannot read cell data array
"pressure" <BR>from PointData in piece 0. The data array in the
element may be too short.<BR><BR>The format of my output file is as
follows:<BR><BR><?xml version="1.0"?><BR><VTKFile
type="ImageData" version="0.1"
byte_order="LittleEndian"><BR><ImageData WholeExtent="0 422 0 242 0
1" Origin="0 0 0" Spacing="1 1 1"><BR><Piece Extent="0 422 0 242 0
1"><BR><PointData><BR></PointData><BR><CellData
Scalars="pressure"><BR><DataArray type="Float32" Name="pressure"
format="appended"
offset="0"/><BR></CellData><BR></Piece><BR></ImageData><BR><AppendedData
encoding="raw"><BR>_BINARYDATA<BR></AppendedData><BR></VTKFile><BR><BR>Note
following an error message I have added an _ at the start of the binary
<BR>data. Is this required?<BR><BR>One final thing, when using appended
data, how do you calculate what the <BR>offset should
be?<BR><BR>Thanks<BR>David</DIV><PRE><HR SIZE=4 width="90%">
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