Sweeps

ITensors.ITensorMPS.Sweeps — Type

A Sweeps objects holds information about the various parameters controlling a density matrix renormalization group (DMRG) or similar matrix product state (MPS) calculation.

For a Sweeps object sw the available parameters are:

nsweep(sw) – the number of sweeps to do
maxdim(sw,n) – maximum MPS bond dimension for sweep n
mindim(sw,n) – minimum MPS bond dimension for sweep n
cutoff(sw,n) – truncation error cutoff for sweep n
noise(sw,n) – noise term coefficient for sweep n

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ITensors.ITensorMPS.Sweeps — Method

Sweeps(d::AbstractMatrix)

Sweeps(nsweep::Int, d::AbstractMatrix)

Make a sweeps object from a matrix of input values. The first row should be strings that define which variables are being set ("maxdim", "cutoff", "mindim", and "noise").

If the number of sweeps are not specified, they are determined from the size of the input matrix.

Examples

julia > Sweeps(
  [
    "maxdim" "mindim" "cutoff" "noise"
    50 10 1e-12 1E-7
    100 20 1e-12 1E-8
    200 20 1e-12 1E-10
    400 20 1e-12 0
    800 20 1e-12 1E-11
    800 20 1e-12 0
  ],
)
Sweeps
1cutoff = 1.0E-12, maxdim = 50, mindim = 10, noise = 1.0E-07
2cutoff = 1.0E-12, maxdim = 100, mindim = 20, noise = 1.0E-08
3cutoff = 1.0E-12, maxdim = 200, mindim = 20, noise = 1.0E-10
4cutoff = 1.0E-12, maxdim = 400, mindim = 20, noise = 0.0E+00
5cutoff = 1.0E-12, maxdim = 800, mindim = 20, noise = 1.0E-11
6cutoff = 1.0E-12, maxdim = 800, mindim = 20, noise = 0.0E+00

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Modifying Sweeps Objects

ITensors.ITensorMPS.setmaxdim! — Function

maxdim!(sw::Sweeps,maxdims::Int...)

Set the maximum MPS bond dimension for each sweep by providing up to nsweep(sw) values. If fewer values are provided, the last value is repeated for the remaining sweeps.

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ITensors.ITensorMPS.setcutoff! — Function

cutoff!(sw::Sweeps,maxdims::Int...)

Set the MPS truncation error used for each sweep by providing up to nsweep(sw) values. If fewer values are provided, the last value is repeated for the remaining sweeps.

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ITensors.ITensorMPS.setnoise! — Function

noise!(sw::Sweeps,maxdims::Int...)

Set the noise-term coefficient used for each sweep by providing up to nsweep(sw) values. If fewer values are provided, the last value is repeated for the remaining sweeps.

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ITensors.ITensorMPS.setmindim! — Function

mindim!(sw::Sweeps,maxdims::Int...)

Set the minimum MPS bond dimension for each sweep by providing up to nsweep(sw) values. If fewer values are provided, the last value is repeated for the remaining sweeps.

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