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85 lines
3.7 KiB
Python
85 lines
3.7 KiB
Python
"""
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Custom Loss functions and metrics for training/analysis
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"""
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from tf_funcs import *
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import tensorflow as tf
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# The following loss functions all expect the lpcnet model to output the lpc prediction
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# Computing the excitation by subtracting the lpc prediction from the target, followed by minimizing the cross entropy
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def res_from_sigloss():
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def loss(y_true,y_pred):
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p = y_pred[:,:,0:1]
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model_out = y_pred[:,:,1:]
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e_gt = tf_l2u(tf_u2l(y_true) - tf_u2l(p))
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e_gt = tf.round(e_gt)
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e_gt = tf.cast(e_gt,'int32')
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sparse_cel = tf.keras.losses.SparseCategoricalCrossentropy(reduction=tf.keras.losses.Reduction.NONE)(e_gt,model_out)
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return sparse_cel
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return loss
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# Interpolated and Compensated Loss (In case of end to end lpcnet)
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# Interpolates between adjacent embeddings based on the fractional value of the excitation computed (similar to the embedding interpolation)
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# Also adds a probability compensation (to account for matching cross entropy in the linear domain), weighted by gamma
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def interp_mulaw(gamma = 1):
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def loss(y_true,y_pred):
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p = y_pred[:,:,0:1]
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model_out = y_pred[:,:,1:]
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e_gt = tf_l2u(tf_u2l(y_true) - tf_u2l(p))
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prob_compensation = tf.squeeze((K.abs(e_gt - 128)/128.0)*K.log(256.0))
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alpha = e_gt - tf.math.floor(e_gt)
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alpha = tf.tile(alpha,[1,1,256])
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e_gt = tf.cast(e_gt,'int32')
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e_gt = tf.clip_by_value(e_gt,0,254)
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interp_probab = (1 - alpha)*model_out + alpha*tf.roll(model_out,shift = -1,axis = -1)
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sparse_cel = tf.keras.losses.SparseCategoricalCrossentropy(reduction=tf.keras.losses.Reduction.NONE)(e_gt,interp_probab)
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loss_mod = sparse_cel + gamma*prob_compensation
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return loss_mod
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return loss
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# Same as above, except a metric
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def metric_oginterploss(y_true,y_pred):
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p = y_pred[:,:,0:1]
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model_out = y_pred[:,:,1:]
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e_gt = tf_l2u(tf_u2l(y_true) - tf_u2l(p))
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prob_compensation = tf.squeeze((K.abs(e_gt - 128)/128.0)*K.log(256.0))
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alpha = e_gt - tf.math.floor(e_gt)
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alpha = tf.tile(alpha,[1,1,256])
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e_gt = tf.cast(e_gt,'int32')
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e_gt = tf.clip_by_value(e_gt,0,254)
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interp_probab = (1 - alpha)*model_out + alpha*tf.roll(model_out,shift = -1,axis = -1)
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sparse_cel = tf.keras.losses.SparseCategoricalCrossentropy(reduction=tf.keras.losses.Reduction.NONE)(e_gt,interp_probab)
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loss_mod = sparse_cel + prob_compensation
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return loss_mod
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# Interpolated cross entropy loss metric
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def metric_icel(y_true, y_pred):
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p = y_pred[:,:,0:1]
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model_out = y_pred[:,:,1:]
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e_gt = tf_l2u(tf_u2l(y_true) - tf_u2l(p))
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alpha = e_gt - tf.math.floor(e_gt)
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alpha = tf.tile(alpha,[1,1,256])
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e_gt = tf.cast(e_gt,'int32')
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e_gt = tf.clip_by_value(e_gt,0,254) #Check direction
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interp_probab = (1 - alpha)*model_out + alpha*tf.roll(model_out,shift = -1,axis = -1)
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sparse_cel = tf.keras.losses.SparseCategoricalCrossentropy(reduction=tf.keras.losses.Reduction.NONE)(e_gt,interp_probab)
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return sparse_cel
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# Non-interpolated (rounded) cross entropy loss metric
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def metric_cel(y_true, y_pred):
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p = y_pred[:,:,0:1]
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model_out = y_pred[:,:,1:]
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e_gt = tf_l2u(tf_u2l(y_true) - tf_u2l(p))
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e_gt = tf.round(e_gt)
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e_gt = tf.cast(e_gt,'int32')
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e_gt = tf.clip_by_value(e_gt,0,255)
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sparse_cel = tf.keras.losses.SparseCategoricalCrossentropy(reduction=tf.keras.losses.Reduction.NONE)(e_gt,model_out)
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return sparse_cel
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# Variance metric of the output excitation
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def metric_exc_sd(y_true,y_pred):
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p = y_pred[:,:,0:1]
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e_gt = tf_l2u(tf_u2l(y_true) - tf_u2l(p))
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sd_egt = tf.keras.losses.MeanSquaredError(reduction=tf.keras.losses.Reduction.NONE)(e_gt,128)
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return sd_egt
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