no_random_shift

Do not shift this rank-1 lattice

Specification

• Alias: None

• Arguments: None

Description

By default, the lattice points will be shifted using a random shift vector. This means that the points will be generated according to

\[\boldsymbol{t}^{(i)} = \left\{ \frac{i \boldsymbol{z}}{N} + \Delta \right\}\]

where \(\Delta\) is a \(d\)-dimensional vector with standard uniform random points. When this keyword is specified, the lattice points will not be shifted. This means that the same set of lattice points will be generated, irrespective of the value of the random seed. In that case, the first untransformed point in the sequence will always be \(\boldsymbol{t}^{(0)} = (0, 0, \ldots, 0)\).

Examples

environment
  tabular_data
    tabular_data_file = 'samples.dat'
    freeform

method
  sampling
    samples 8
    sample_type
      low_discrepancy
        rank_1_lattice
          generating_vector inline 1 5 # this is a Fibonacci lattice
          m_max 3 # 8 points in total
          no_random_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