nifty8.library.adjust_variances module#
- do_adjust_variances(position, A, minimizer, xi_key='xi', samples=[])[source]#
Adjusts the variance of xi_key to be represented by amplitude_operator.
Solves a constant likelihood optimization of the form phi = A * position[xi_key] under the constraint that phi remains constant.
The field indexed by xi_key is desired to be a Gaussian white Field, thus variations that are more easily represented by A will be absorbed in A.
- Parameters:
position (
nifty8.field.Field,nifty8.multi_field.MultiField) – Contains the initial values for amplitude_operator and the key xi_key, to be adjusted.A (Operator) – Gives the amplitude when evaluated at position.
minimizer (Minimizer) – Used to solve the optimization problem.
xi_key (String) – Key of the Field containing undesired variations. This Field is contained in position.
samples (
nifty8.field.Field,nifty8.multi_field.MultiField, optional) – Residual samples of position. If samples are supplied then phi remains only approximately constant. Default: [].
- Returns:
The new position after variances have been adjusted.
- Return type:
- make_adjust_variances_hamiltonian(a, xi, position, samples=[], scaling=None, ic_samp=None)[source]#
Creates a Hamiltonian for constant likelihood optimizations.
Constructs a Hamiltonian to solve constant likelihood optimizations of the form phi = a * xi under the constraint that phi remains constant.
xi is desired to be a Gaussian white Field, thus variations that are more easily represented by a should be absorbed in a.
- Parameters:
a (Operator) – Gives the amplitude when evaluated at position.
xi (Operator) – Field Adapter selecting a part of position. xi is desired to be a Gaussian white Field.
position (
nifty8.field.Field,nifty8.multi_field.MultiField) – Contains the initial values for the operators a and xi, to be adjustedsamples (
nifty8.field.Field,nifty8.multi_field.MultiField) – Residual samples of position.scaling (Float) – Optional rescaling of the Likelihood.
ic_samp (Controller) – Iteration Controller for Hamiltonian.
- Returns:
A Hamiltonian that can be used for further minimization.
- Return type: