fefgGet (line 224) running out of memory

[soichih]

We've been seeing a lot of out-of-memory issue with encode lately.

Out of memory. Type HELP MEMORY for your options.

Error in unique


Error in unique


Error in fefgGet (line 224)


Error in feSet (line 75)


Error in feConnectomeInit (line 52)

This might be happening because we started feeding track.tck output from mrtrix3 act app, which output somewhat more fibers and track.tck file size is slightly larger (1.69GB)

tckinfo.txt
 
***********************************
  Tracks file: "track.tck"
    act:                  5tt.mif
    backtrack:            variable
    count:                675000
    crop_at_gmwmi:        1
    downsample_factor:    3
    fod_power:            0.25
    init_threshold:       variable
    lmax:                 variable
    max_angle:            variable
    max_num_seeds:        15000000
    max_num_tracks:       15000
    max_seed_attempts:    1000
    max_trials:           1000
    method:               variable
    mrtrix_version:       3.0_RC3
    output_step_size:     0.625
    rk4:                  0
    samples_per_step:     4
    sh_precomputed:       1
    source:               variable
    step_size:            variable
    stop_on_all_include:  0
    threshold:            variable
    timestamp:            1550301026.1405482292
    total_count:          675000
    unidirectional:       0

I will benchmark / profile the memory usage, but if @ccaiafa @francopestilli have any hunch as to what might be causing this issue, please let me know!

[francopestilli]

@soichih is this inside a docker container?

[francopestilli]

what is the size of 'val'? and that of fg.fibers?

encode/life/utility/fefgGet.m

Line 224 in c6d514a

val = unique(val,'rows');

[ccaiafa]

Hi @soichih
You may change the number of batches to make sure each batch fits in memory when ENCODE model is built. Best. Cesar

[soichih]

We are running inside singularity, and singularity itself doesn't impose any memory limit. If we runt it on karst, it should have access to all 32g available. For app-life, however, we only tell the #PBS that we use 24gb max. so the scheduler will kill the job if are using more than that, but the error messsage we are seeing is from matlab running out of memory.

[francopestilli]

@soichih I just realized this is an mrtrix3 file. We never tested those files in matlab. Is it the case that is read correctly? There can be something in the header that makes them incompatible with fgRead. I would dlook into fg.fibers and see how the fibers look and the size.

[daducci]

Hi @francopestilli , do you have any update on this issue by any chance? I was trying to run LiFE on a .tck tractogram with 5M streamlines to test the new version (encode) as it looks cool. But we run out of memory on a server with 64 GB of ram; it looks like it requires about 100GB. I was wondering whether we are doing something wrong, as the new version should be optimized for memory consumption. Any insight? Thanks, Ale

[francopestilli]

Hi @francopestilli , do you have any update on this issue by any chance? I was trying to run LiFE on a .tck tractogram with 5M streamlines to test the new version (encode) as it looks cool. But we run out of memory on a server with 64 GB of ram; it looks like it requires about 100GB. I was wondering whether we are doing something wrong, as the new version should be optimized for memory consumption. Any insight? Thanks, Ale

@daducci let's me look into this. Which branch of the repo are using? master?

[daducci]

Yes, master branch in this repo (https://github.com/brain-life/encode). Then we used the demo_LiFE.m script to process this tractogram. Thanks for the quick reply!

[francopestilli]

Hi @daducci

Take a look at this code: https://github.com/brain-life/encode/blob/master/life/fe/feConnectomeEncoding.m#L29

and: https://github.com/brain-life/encode/blob/master/life/fe/feConnectomeEncoding.m#L58

We provide some educated-guesses for the size of the memory that can be allocated and for the size fo the batches used to process the streamlines as input.

If the guess is not appropriate for your OS and/or the number of streamlines you are using (much bigger than we normally use), the initialization is likely to fail.

You should be able to change the batch size so that each batch can fit in memory. Does it make sense?

[ccaiafa]

Thanks @francopestilli for the clarification.
Hi @daducci, let me add something more. As explained in our paper, the information of the whole connectome is encoded into an extremely large but very sparse 3D array (tensor Phi), whose dimensions corresponds to orientation x voxel x fiber. To avoid explosion of memory requirements during the tensor building, we divide the connectome in groups of fibers (batches), we create a sparse 3D tensor for each group and, finally, we obtain the objective sparse 3D tensor by concatenating all sub-tensors along the 3rd dimension.
If you still have memory problems, you can try to continue increasing the number of batches (groups of fibers).
I hope it helps.
Best
Cesar

[daducci]

Thank you both, I really appreciate your help! Indeed, the fitting does not fail, it simply requires about 100GB of RAM and 55h/brain to complete (probably because of swapping I suspect). But then the coefficients look fine. So, if I understood correctly, you suggest reducing the size of the batches so that the amount of memory is reduced, am I right?

[francopestilli]

Hi @daducci correct, it should. But the RAM you measure worry me a little. We never see such large memory usage. Maybe your streamlines are sampled at very high resolution also (we use 1mm node spacing)? Anyways, reducing the batch size should work, I am just confused by the 100GB! If things are still so crazy (55h), would you feel comfortable sharing the dataset for a local test on our side (dwi+BVECS?BVALS and .tck file)?

[daducci]

Hi Franco and Cesar, of course, there's no problem sharing the data! We are just running a few more tests to provide you with correct timings and memory requirements we observe: we fit LIFE to all 3 shells of the HCP dataset, but then saw that in your paper you only use the b=2000 shell, so we are performing this test and will come back to you asap. We also take care of the b0=5 issue.

Meanwhile, we have run some other experiments on a smaller tractogram to match the one in your paper (500k streamlines, iFOD2 algo, default step size 0.625mm, file size 770MB). The aim was to play with the MAXMEM parameter you suggested. Indeed we observed that the time for constructing the fe-structure increased, as expected, but the total amount of ram didn't seem to change. Besides, the ram required at fitting time was about 12GB (our workstation has 64GB). I report hereafter some values we got so far:

• MAXMEM set to default value
  Encoding batch 16 took: 325.317s.
  [feConnectomeInit] fe-structure Memory Storage:3.82 Gb
  Fit process completed in 131.359 minutes
  Memory used by Matlab creating the dictionary 12GB, fitting 10GB
• MAXMEM set to half its default value
  Encoding batch 32 took: 510.341s.
  [feConnectomeInit] fe-structure Memory Storage:3.82 Gb
  Memory used by Matlab creating the dictionary 12GB, fitting 10GB
  Fit process completed in 131.851 minutes

As you can see, fitting time and memory requirements do not change, only the construction time does. What are we doing wrong?

[ccaiafa]

Hi @daducci,
Thanks for sharing the results. I think they make sense.
Using batched constructing of tensor PHI reduces memory requirements only during building. The final result, i.e. the obtained full sparse tensor PHI is the same, independently of the number of batches used. Each batch has the goal to construct a piece of the final tensor PHI.
Regarding time for fitting, your numbers are reasonable, maybe a little bit large. I remember that for our paper results each brain needed approximately 45mins to be fit on Indiana University servers.
Best
Cesar

[daducci]

Dear Cesar,

the test on the 4M streamlines and using only the b=2000 shell just finished, here are the outcomes:

HCP subject 119833
MAXMEM default value
Encoding batch 26 took: 1.33 hours.
[feConnectomeInit] fe-structure Memory Storage: 28.00 Gb
Memory used by Matlab creating the dictionary 100GB, fitting 48GB
Fit process completed in 22.88 hours

Do these numbers make sense? If so, that's ok, we are just worried we are doing something wrong. Here is the link to the data in case you want to give it a try.