"No space left on device" error when using write_to_disk feature in Itensor Julia

Question

Hi there,

I'm using writewhenmaxdim_exceeds keyword in dmrg to implement writing to disk, but I met the error message shown below. It says that there is not space left on the disk, but I checked that there is enough space in the directory (there is 2TB available space and the tensors are expected to occupy around 400GB). Can anyone help?

DMRG Command:
energy,psi = dmrg(H,psi,sweeps; writewhenmaxdim_exceeds=10000)

Space of the Directory
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/md2 15625699328 13595822844 2029876484 88% /scratch

Error Message:
ERROR: LoadError: SystemError: close: No space left on device
Stacktrace:
[1] systemerror(p::String, errno::Int32; extrainfo::Nothing)
@ Base ./error.jl:174
[2] #systemerror#68
@ ./error.jl:173 [inlined]
[3] systemerror
@ ./error.jl:173 [inlined]
[4] close
@ ./iostream.jl:63 [inlined]
[5] open(::Serialization.var"#1#2"{ITensor}, ::String, ::Vararg{String}; kwargs::Base.Pairs{Symbol, Union{}, Tuple{}, NamedTuple{(), Tuple{}}})
@ Base ./io.jl:332
[6] open
@ ./io.jl:328 [inlined]
[7] serialize
@ ~/julia-1.7.2/share/julia/stdlib/v1.7/Serialization/src/Serialization.jl:775 [inlined]
[8] setindex!
@ ~/.julia/packages/SerializedElementArrays/cdFxy/src/SerializedElementArrays.jl:78 [inlined]
[9] makeL!(P::ITensors.DiskProjMPO, psi::MPS, k::Int64)
@ ITensors ~/.julia/dev/ITensors/src/mps/abstractprojmpo.jl:164
[10] makeL!
@ ~/.julia/dev/ITensors/src/mps/diskprojmpo.jl:103 [inlined]
[11] position!
@ ~/.julia/dev/ITensors/src/mps/abstractprojmpo.jl:219 [inlined]
[12] macro expansion
@ ~/.julia/dev/ITensors/src/mps/dmrg.jl:206 [inlined]
[13] macro expansion
@ ~/.julia/packages/TimerOutputs/LDL7n/src/TimerOutput.jl:252 [inlined]
[14] macro expansion
@ ~/.julia/dev/ITensors/src/mps/dmrg.jl:205 [inlined]
[15] macro expansion
@ ./timing.jl:299 [inlined]
[16] dmrg(PH::ProjMPO, psi0::MPS, sweeps::Sweeps; kwargs::Base.Pairs{Symbol, Int64, Tuple{Symbol}, NamedTuple{(:writewhenmaxdimexceeds,), Tuple{Int64}}})
@ ITensors ~/.julia/dev/ITensors/src/mps/dmrg.jl:186
[17] #dmrg#958
@ ~/.julia/dev/ITensors/src/mps/dmrg.jl:47 [inlined]

Comments

BTW, where are the tensors stored when the write to disk feature is functioning? I ran the following example code but didnot find any new files showing up in the directory where my code is located.

https://github.com/ITensor/ITensors.jl/blob/main/examples/dmrg/write_to_disk/1d_heisenberg.jl

Answer 1

It turns out that the intermediate tensors are by default stored in the "/tmp" directory, which in my case has small disk storage. To resolve the issue, I changed the environment variable TMPDIR to a location with a bigger storage.