""" Copyright (C) 2018 Patrick Schwab, ETH Zurich Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. """ import tensorflow as tf # SOURCE: https://github.com/clinicalml/cfrnet, MIT-License def pdist2(X, Y): """ Computes the squared Euclidean distance between all pairs x in X, y in Y """ C = -2*tf.matmul(X, tf.transpose(Y)) nx = tf.reduce_sum(tf.square(X), 1, keep_dims=True) ny = tf.reduce_sum(tf.square(Y), 1, keep_dims=True) D = (C + tf.transpose(ny)) + nx return tf.sqrt(D + 1e-8) # SOURCE: https://github.com/clinicalml/cfrnet, MIT-License def cf_nn(x, t): It = tf.where(tf.equal(t, 1))[:, 0] Ic = tf.where(tf.equal(t, 0))[:, 0] x_c = tf.gather(x, Ic) x_t = tf.gather(x, It) D = pdist2(x_c, x_t) nn_t = tf.gather(Ic, tf.argmin(D, 0)) nn_c = tf.gather(It, tf.argmin(D, 1)) return tf.stop_gradient(nn_t), tf.stop_gradient(nn_c) # SOURCE: https://github.com/clinicalml/cfrnet, MIT-License def pehe_nn(yf_p, ycf_p, y, x, t, nn_t=None, nn_c=None): if nn_t is None or nn_c is None: nn_t, nn_c = cf_nn(x, t) It = tf.where(tf.equal(t, 1))[:, 0] Ic = tf.where(tf.equal(t, 0))[:, 0] ycf_t = 1.0*tf.gather(y, nn_t) eff_nn_t = ycf_t - 1.0*tf.gather(y, It) eff_pred_t = tf.gather(ycf_p, It) - tf.gather(yf_p, It) eff_pred = eff_pred_t eff_nn = eff_nn_t pehe_nn = tf.sqrt(tf.reduce_mean(tf.square(eff_pred - eff_nn))) return pehe_nn def pehe_loss(y_true, y_pred, t, x, num_treatments): total, num_elements = 0, 0. for i in range(num_treatments): for j in range(num_treatments): if j >= i: continue t1_indices = tf.where(tf.equal(t, i))[:, 0] t2_indices = tf.where(tf.equal(t, j))[:, 0] these_x = tf.concat([tf.gather(x, t1_indices), tf.gather(x, t2_indices)], axis=0) y_pred_these_treatments = tf.concat([tf.gather(y_pred, t1_indices), tf.gather(y_pred, t2_indices)], axis=0) y_true_these_treatments = tf.concat([tf.gather(y_true, t1_indices), tf.gather(y_true, t2_indices)], axis=0) these_treatments = tf.concat([tf.ones((tf.shape(t1_indices)[0],), dtype="int32") * i, tf.ones((tf.shape(t2_indices)[0],), dtype="int32") * j], axis=0) these_y_pred_f = tf.gather(y_pred_these_treatments, tf.concat([tf.range(tf.shape(y_pred_these_treatments)[0]), these_treatments], axis=-1)) these_y_true_f = y_true_these_treatments inverse_treatments = tf.concat([tf.ones((tf.shape(t1_indices)[0],), dtype="int32") * j, tf.ones((tf.shape(t2_indices)[0],), dtype="int32") * i], axis=0) these_y_pred_cf = tf.gather(y_pred_these_treatments, tf.concat([tf.range(tf.shape(y_pred_these_treatments)[0]), inverse_treatments], axis=-1)) these_treatments = tf.concat([tf.zeros((tf.shape(t1_indices)[0],), dtype="int32"), tf.ones((tf.shape(t2_indices)[0],), dtype="int32")], axis=0) total += pehe_nn(these_y_pred_f, these_y_pred_cf, these_y_true_f, these_x, these_treatments) num_elements += 1. return total / num_elements