t_scramble

Number of rows in the affine scramble matrices

Specification

• Alias: None

• Arguments: INTEGER

• Default: 64

Description

Use this option to set the number of rows in the linear scramble matrices. A linear scrambling matrix is a lower-tridiagonal matrix with shape t_scramble x t_max with 1s on the diagonal, i.e.,

1 0 0 0 0
x 1 0 0 0
x x 1 0 0
x x x 1 0
x x x x 1

which is encoded as a vector of length t_max, with integer entries of t_scramble bits each, encoding the columns of the scramble matrix (analogous to the way generating matrices are stored). The value of t_scramble must be greater than or equal to t_max. Note that this option has no effect if the keyword no_scrambling is specified. By default, Dakota uses t_scramble = t_max.

Examples

environment
  tabular_data
    tabular_data_file = 'samples.dat'
    freeform

method
  sampling
    samples 32
    sample_type
      low_discrepancy
        digital_net
          generating_matrices inline
            1 2 4 8 16
            # this encodes the generating matrix
            # 1 0 0 0 0
            # 0 1 0 0 0
            # 0 0 1 0 0
            # 0 0 0 1 0
            # 0 0 0 0 1
            1 3 5 15 17
            # this encodes the generating matrix
            # 1 1 1 1 1
            # 0 1 0 1 0
            # 0 0 1 1 0
            # 0 0 0 1 0
            # 0 0 0 0 1
          m_max 5
          t_max 5
          t_scramble 5
          no_digital_shift

variables
  uniform_uncertain = 2
    lower_bounds 0.0 0.0
    upper_bounds 1.0 1.0

interface
  analysis_drivers = 'genz'
  analysis_components = 'cp1'
  direct

responses
  response_functions = 1
  no_gradients
  no_hessians