Constrains the weights incident to each hidden unit to have unit norm.
constraint_unitnorm(axis = 0)The axis along which to calculate weight norms. For instance, in
a dense layer the weight matrix has shape input_dim, output_dim,
set axis to 0 to constrain each weight vector of length input_dim,.
In a convolution 2D layer with dim_ordering="tf", the weight tensor has
shape rows, cols, input_depth, output_depth, set axis to c(0, 1, 2)
to constrain the weights of each filter tensor of size rows, cols, input_depth.
Other constraints: constraint_maxnorm,
constraint_minmaxnorm,
constraint_nonneg