#1 TT_DEMO_MLEM_CONEBEAM matlab crash

[Lukas Zubal]

Hi,
I just compiled lastest niftyrec and some functions worked without any problems.

When I tried to run TT_DEMO_MLEM_CONEBEAM it crusshes matlab immediatelly. I found that this is on line 81 in function tt_backproject_ray_mex.
I tried to turn off GPU setting, this causes also crush, but i get this response from matlab:
--------------------------------------------------------------------------------------------------------
Segmentation violation detected at Sat Feb 16 20:04:56 2013
------------------------------------------------------------------------

Configuration:
Crash Decoding : Disabled
Default Encoding: windows-1252
MATLAB License : 161052
MATLAB Root : C:\Program Files (x86)\MATLAB\R2011a
MATLAB Version : 7.12.0.635 (R2011a)
Operating System: Microsoft Windows 7
Processor ID : x86 Family 6 Model 10 Stepping 7, GenuineIntel
Virtual Machine : Java 1.6.0_17-b04 with Sun Microsystems Inc. Java HotSpot(TM) Client VM mixed mode
Window System : Version 6.1 (Build 7601: Service Pack 1)

Fault Count: 1

Abnormal termination:
Segmentation violation

Register State (from fault):
EAX = 00000080 EBX = 2af30030
ECX = 2b720e38 EDX = 2b721034
ESP = 00b9d3c0 EBP = 00b9d50c
ESI = 2b730e34 EDI = 00200401

EIP = 58083776 EFL = 00210202

CS = 00000023 DS = 0000002b SS = 0000002b
ES = 0000002b FS = 00000053 GS = 0000002b

Stack Trace (from fault):
[ 0] 0x58083776 C:/Program Files (x86)/nifty_rec/niftyrec/matlab/tt_backproject_ray_mex.mexw32+00014198 ( mexFunction+010102 )
[ 1] 0x58082bc1 C:/Program Files (x86)/nifty_rec/niftyrec/matlab/tt_backproject_ray_mex.mexw32+00011201 ( mexFunction+007105 )
[ 2] 0x724368e5 C:/Windows/WinSxS/x86_microsoft.vc90.crt_1fc8b3b9a1e18e3b_9.0.30729.4940_none_50916076bcb9a742/MSVCR90.dll+00420069 ( realloc+001257 )
[ 3] 0x58081d06 C:/Program Files (x86)/nifty_rec/niftyrec/matlab/tt_backproject_ray_mex.mexw32+00007430 ( mexFunction+003334 )

This error was detected while a MEX-file was running. If the MEX-file
is not an official MathWorks function, please examine its source code
for errors. Please consult the External Interfaces Guide for information
on debugging MEX-files.

If this problem is reproducible, please submit a Service Request via:
http://www.mathworks.com/support/contact_us/

A technical support engineer might contact you with further information.

Thank you for your help.
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I also tried this for both 32bit and 64bit versions of matlab.

There is also minor troubles with variable checking inside some functions. Variable testing for example in file et_backproject.m:
if not(exist('background'))
background = 0;
end

Can make troubles, when 'background' is class or function. I suggest to replace this code with:
if not(exist('background','var'))
background = 0;
end

Thanks to your work!

Regards,
Lukas