# Multi-thread Run Problem
**URL:** https://castor-project.discourse.group/t/multi-thread-run-problem/151
**Category:** General Discussions
**Created:** [May 26, 2020, 2:13pm UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151 "2020-05-26T14:13:21Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@Virtuall](https://castor-project.discourse.group/u/Virtuall)
#### Post date: [May 26, 2020, 2:13pm UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/1 "2020-05-26T14:13:21Z")
Dear all,
I am testing CASToR performance on multi-thread running, but it looks like using the multi-thread function is not very stable.
Before applying multi-thread to recon, every job was good. But recon jobs always dumped with unrecognized problem since I used multi-thread as below:
```auto
***Error in `castor-recon': munmap_chunk(): invalid pointer: 0x0000000002259380***
```
Did anyone ever see this problem before?
Any answer will be highly appreciated! Thank you!
Best,
---
### Author:  [@tmerlin](https://castor-project.discourse.group/u/tmerlin)
#### Post date: [May 28, 2020, 11:04am UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/2 "2020-05-28T11:04:27Z")
Hi Xinjie,
On which kind of dataset did you get this problem ? Did it occur on every data you tried to reconstruct or just some of them ?
Best,
Thibaut
Xinjie Cao \<[xinjie.cao@stonybrook.edu](mailto:xinjie.cao@stonybrook.edu)\> a écrit :
---
### Author:  [@sstute](https://castor-project.discourse.group/u/sstute)
#### Post date: [May 28, 2020, 11:40am UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/3 "2020-05-28T11:40:34Z")
Hi,
I already got strange results like that when I switch between different compilation. The reason was that sometimes I forgot to clean the compilation. Did you carefully use “make clean” command between each compilation ?
Simon
---
### Author:  [@Virtuall](https://castor-project.discourse.group/u/Virtuall)
#### Post date: [June 8, 2020, 3:20pm UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/4 "2020-06-08T15:20:00Z")
Hi Thibaut and Simon,
I have compiled two different Castor versions for multi-thread running and single core in separate directories, respectively. The multi-thread is running well now, but single core test had a problem when I move from a lower resolution configuration to a higher one like below,
**First recon try** :
```auto
castor-recon -df Brain_Double_df.Cdh -opti MLEM -it 10:16 -proj joseph -conv gaussian,4.,4.5,3.5::psf -dim 100,100,16 -vox 2.5,2.5,10. -oit -1 -dout Brain_Double
.........
iIterativeAlgorithm::StepAfterSubsetLoop() -> Save image at iteration 10
vAlgorithm::IterateCPU() -> Total time spent | User: 3699 sec | CPU: 3.6990100e+03 sec
sChronoManager::Display() -> Results from the profiling
.........
--> Custom update step 1: 00 hours 00 mins 00 secs 000 ms
```
**Second recon try** :
```auto
castor-recon -df Brain_Double_df.Cdh -opti MLEM -it 2:10 -proj joseph -conv gaussian,4.,4.5,3.5::psf -dim 200,200,16 -vox 1.25,1.25,10. -oit -1 -dout Brain_Double_2
***Break*** segmentation violation
```
---
### Author:  [@tmerlin](https://castor-project.discourse.group/u/tmerlin)
#### Post date: [June 9, 2020, 2:56pm UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/5 "2020-06-09T14:56:34Z")
Hi Xinjie,
Does the crash occur directly after you launch the the reconstruction. Could you run it with -vb 3 to have a bit more feedback ?
There is no reason why you couldn’t change reconstruction parameters between two consecutive reconstructions.
Maybe you could send us/upload your dataset & geometry file so we have a closer look at the problem ?
Best regards,
---
### Author:  [@Virtuall](https://castor-project.discourse.group/u/Virtuall)
#### Post date: [June 14, 2020, 12:01am UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/6 "2020-06-14T00:01:04Z")
Hi tmerlin,
Here is my dataset, geometry and entire error log. Hope you could find something!
[Brain\_Double\_df.Cdf](https://drive.google.com/a/stonybrook.edu/file/d/1wC4X99y4ATwDWGdrh8OoHfPmeA8l_m2G/view?usp=drive_web) 
[Brain\_Double\_df.Cdh](https://drive.google.com/a/stonybrook.edu/file/d/1CFoCBMTOVrLgbP-chCu4bXVf379jWEQR/view?usp=drive_web) 
Best,
[Error-Log](https://castor-project.discourse.group/uploads/short-url/rqkvBHVdoWAfgOEbWBHLfJnfpmd) (43.7 KB)
[Brain\_Double.geom](https://castor-project.discourse.group/uploads/short-url/4hT8drb3JIldzQeJr4FPpdrLFsF.geom) (1.84 KB)
---
### Author:  [@tmerlin](https://castor-project.discourse.group/u/tmerlin)
#### Post date: [June 19, 2020, 6:55pm UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/7 "2020-06-19T18:55:24Z")
Hi Xinjie,
Thanks for your data. I could reproduce your error and it seems it is linked to the Joseph projector. In particular, there is a hard-coded tolerance factor used to compute the planes which are crossed by the lines. Decreasing that factor seems to remove the crash in my tests.
So a quick fix may be to reduce that threshold (you can replace the _src/projector/iProjectorJoseph.cc_ file by the one in attached, then recompile castor).
I am not sure yet whether the crash is limited to that factor. Let me know if it fixes the error for you.
Best,
Thibaut
[iProjectorJoseph.cc](https://castor-project.discourse.group/uploads/short-url/acBYoNfHXsIvbkVyMAFTx89D6XG.cc) (62.8 KB)
---
### Author:  [@Virtuall](https://castor-project.discourse.group/u/Virtuall)
#### Post date: [June 24, 2020, 9:39pm UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/8 "2020-06-24T21:39:59Z")
Hi Tmerlin,
It looks like there is no error now, i will let you know if the error appears again. Thanks!
Best,
---
### Author:  [@h.rashidykanan](https://castor-project.discourse.group/u/h.rashidykanan)
#### Post date: [January 15, 2024, 12:29pm UTC](https://castor-project.discourse.group/t/multi-thread-run-problem/151/9 "2024-01-15T12:29:28Z")
Dear Virtuall,
Could you please share again your dataset (Brain\_Double\_df.Cdf and Brain\_Double\_df.Cdh). I want to check out my installed CASToR using Multi-thread.
Also, Could you please describe how to create this dataset. I assume that, you converted a dataset from a specific scanner (interfile) to CASToR interfile format. Thank you very much in advance.