Implementation of L1, L2, ElasticNet, GroupLasso and GroupSparseRegularization

1. Publication available here: [https://towardsdatascience.com/different-types-of-regularization-on-neuronal-network-with-pytorch-a9d6faf4793e]
2. Implemented in pytorch. This is an attempt to provide different type of regularization of neuronal network weights in pytorch.
3. The regularization can be applied to one set of weight or all the weights of the model

Metrics Scores table

Regularization	Test Accuracy	Best HyperParameters
L1	98.3193	'batch_size': 32, 'ld_reg': 1e-05, 'lr': 0.0001, 'n_epoch': 200
L2	99.1596	'batch_size': 32, 'ld_reg': 1e-06, 'lr': 0.0001, 'n_epoch': 200
EL	98.3193	'alpha_reg': 0.9, 'batch_size': 32, 'ld_reg': 1e-05, 'lr': 0.001, 'n_epoch': 200
GL	97.4789	'batch_size': 32, 'ld_reg': 1e-07, 'lr': 0.0001, 'n_epoch': 200
SGL	76.4705	'batch_size': 128, 'ld_reg': 1e-06, 'lr': 1e-05, 'n_epoch': 200
FC	90.7563	'batch_size': 128, 'lr': 0.01, 'n_epoch': 200
FC with Weight decay	99.1596	'batch_size': 32, 'lr': 0.0001, 'n_epoch': 200, 'weight_decay': 0.01

Sparsity Percentage table

Model	Layer 1 (%)	Layer 2 (%)	Layer 3(%)
L1	60	80	0
L2	62.5	5	0
EL	85	80	30
GL	7.5	5	0
SGL	92.5	85	30
FC	0	0	0
FC with Weight decay	0	0	0