3 level nested structs leading to out of memory

I'm initializing nested structs as:

struct('nestedLevelOne', repmat({struct('nestedLevelTwo',repmat({zeros(1,1080)}, [1,540]))} , [1,100]));

When I access and store data to these structures this is leading memory issues with 192gb ram on my workstation. Is there I am doing wrong with this?

[Akira Agata]

I could generate this nested structure without any issue.

Could you tell us more detail on the process when you faced the memory issue?

By the way, I would recommend break-down your code to be read easily, like:

c1 = repmat({zeros(1,1080)}, [1,540]);
c2 = repmat({struct('nestedLevelTwo',c1)} , [1,100]);

yourStruct = struct('nestedLevelOne', c2);

[Science Machine]

@Akira Agata when i start reading and writing to the structures with parfor loops, then this quickly leads to memory issue. So i was thinking that was due to

(1) how the structure was initialized (you just checked if the structure 'could' be initialized as such, which is not my issue),

(2) or maybe the fact i'm using nested structures (perhaps another data structure type would be better for lots of data?

Answer 1

[Chunru]

It takes ~472MB memory as shown below.

a = struct('nestedLevelOne', ...
    repmat({struct('nestedLevelTwo',repmat({zeros(1,1080)}, [1,540]))} , [1,100]));
whos

  Name      Size                 Bytes  Class     Attributes

  a         1x100            472192864  struct              

a(1)

ans = struct with fields:
    nestedLevelOne: [1×540 struct]

a(1).nestedLevelOne(1)

ans = struct with fields:
    nestedLevelTwo: [0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 … ]

size(a(1).nestedLevelOne(1).nestedLevelTwo)

ans = 1×2

1 1080

[Science Machine]

@Chunru

I see, a structure i have is 47.69 gb, so I should save that piecemeal. Also, using parfor loops would create copies of this, which would explain why 20 workers crashed it