Optimization

Loss functions

The following functions can be used as the loss_function argument for Metamer and MetamerCTF.

mse	Calculate the MSE between synth_rep and ref_rep.
l2_norm	Calculate the L2-norm of the difference between ref_rep and synth_rep.
relative_sse	Calculate the relative sum of squared errors between two tensors.

Loss function factories

The following functions return a function that can be used as a loss_function, as above.

portilla_simoncelli_loss_factory	Create the loss function required for PortillaSimoncelli metamer synthesis.
groupwise_relative_l2_norm_factory	Create loss function that computes groupwise relative L2 norm for synthesis.

Penalty functions

The following functions operate as penalties.

penalize_range

Calculate quadratic penalty on values outside of allowed_range.