app.py

#! /usr/bin/env python3
# coding=utf-8
# Copyright 2018 The Uber AI Team Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# print
"""
Example command with bag of words:
python examples/run_pplm.py -B space --cond_text "The president" --length 100 --gamma 1.5 --num_iterations 3 --num_samples 10 --stepsize 0.01 --window_length 5 --kl_scale 0.01 --gm_scale 0.95

Example command with discriminator:
python examples/run_pplm.py -D sentiment --class_label 3 --cond_text "The lake" --length 10 --gamma 1.0 --num_iterations 30 --num_samples 10 --stepsize 0.01 --kl_scale 0.01 --gm_scale 0.95
"""

import gradio as gr
import argparse
import json
from operator import add
from typing import List, Optional, Tuple, Union
from random import choice, randint
import numpy as np
import torch
import torch.nn.functional as F
from torch.autograd import Variable
from tqdm import trange
from transformers import GPT2Tokenizer
from transformers.file_utils import cached_path
from transformers.modeling_gpt2 import GPT2LMHeadModel

from pplm_classification_head import ClassificationHead

PPLM_BOW = 1
PPLM_DISCRIM = 2
PPLM_BOW_DISCRIM = 3
SMALL_CONST = 1e-15
BIG_CONST = 1e10

QUIET = 0
REGULAR = 1
VERBOSE = 2
VERY_VERBOSE = 3
VERBOSITY_LEVELS = {
    'quiet': QUIET,
    'regular': REGULAR,
    'verbose': VERBOSE,
    'very_verbose': VERY_VERBOSE,
}

BAG_OF_WORDS_ARCHIVE_MAP = {
    'legal': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/legal.txt",
    'military': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/military.txt",
    'monsters': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/monsters.txt",
    'politics': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/politics.txt",
    'positive_words': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/positive_words.txt",
    'religion': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/religion.txt",
    'science': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/science.txt",
    'space': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/space.txt",
    'technology': "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/bow/technology.txt",
}

DISCRIMINATOR_MODELS_PARAMS = {
    "clickbait": {
        "url": "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/discriminators/clickbait_classifier_head.pt",
        "class_size": 2,
        "embed_size": 1024,
        "class_vocab": {"non_clickbait": 0, "clickbait": 1},
        "default_class": 1,
        "pretrained_model": "gpt2-medium",
    },
    "sentiment": {
        "url": "https://s3.amazonaws.com/models.huggingface.co/bert/pplm/discriminators/SST_classifier_head.pt",
        "class_size": 5,
        "embed_size": 1024,
        "class_vocab": {"very_positive": 2, "very_negative": 3},
        "default_class": 3,
        "pretrained_model": "gpt2-medium",
    },
    "3_PerSoothe": {
        "path": "/content/drive/Shareddrives/COS_IW04_ZL/COSIW04/Discriminators/3_class_opt_lowlr_medgpt/3_PerSoothe_classifier_head_epoch_10.pt",
        "class_size": 3, 
        "embed_size": 1024, 
        "class_vocab": {"soothes": 0, "neutral": 1, "worsens": 2}, 
        "default_class": 2,
        "pretrained_model": "microsoft/DialoGPT-medium", 
    },
    "3_PerSoothe_eot": {
        "path": "/content/drive/Shareddrives/COS_IW04_ZL/COSIW04/Discriminators/3_class_opt_eot_lowlr_medgpt/3_PerSoothe_classifier_head_epoch_10.pt",
        "class_size": 3, 
        "embed_size": 1024, 
        "class_vocab": {"soothes": 0, "neutral": 1, "worsens": 2}, 
        "default_class": 2,
        "pretrained_model": "microsoft/DialoGPT-medium", 
    },
    "3_PerSoothe_lrg": {
        "class_size": 3, 
        "embed_size": 1280, 
        "class_vocab": {"soothes": 0, "neutral": 1, "worsens": 2}, 
        "default_class": 2,
        "pretrained_model": "microsoft/DialoGPT-large", 
    },
    "3_PerSoothe_med": {
        "class_size": 3, 
        "embed_size": 1024, 
        "class_vocab": {"soothes": 0, "neutral": 1, "worsens": 2}, 
        "default_class": 2,
        "pretrained_model": "microsoft/DialoGPT-medium", 
    },
}


def to_var(x, requires_grad=False, volatile=False, device='cuda'):
    if torch.cuda.is_available() and device == 'cuda':
        x = x.cuda()
    elif device != 'cuda':
        x = x.to(device)
    return Variable(x, requires_grad=requires_grad, volatile=volatile)


def top_k_filter(logits, k, probs=False):
    """
    Masks everything but the k top entries as -infinity (1e10).
    Used to mask logits such that e^-infinity -> 0 won't contribute to the
    sum of the denominator.
    """
    if k == 0:
        return logits
    else:
        values = torch.topk(logits, k)[0]
        batch_mins = values[:, -1].view(-1, 1).expand_as(logits)
        if probs:
            return torch.where(logits < batch_mins,
                               torch.ones_like(logits) * 0.0, logits)
        return torch.where(logits < batch_mins,
                           torch.ones_like(logits) * -BIG_CONST,
                           logits)


def perturb_past(
        past,
        model,
        last,
        unpert_past =None,
        unpert_logits=None,
        accumulated_hidden=None,
        grad_norms=None,
        stepsize=0.01,
        one_hot_bows_vectors=None,
        classifier=None,
        class_label=None,
        loss_type=0,
        num_iterations=3,
        horizon_length=1,
        window_length=0,
        decay=False,
        gamma=1.5,
        kl_scale=0.01,
        device='cuda',
        verbosity_level=REGULAR
):
    # Generate inital perturbed past
    grad_accumulator = [
        (np.zeros(p.shape).astype("float32"))
        for p in past
    ]

    if accumulated_hidden is None:
        accumulated_hidden = 0

    if decay:
        decay_mask = torch.arange(
            0.,
            1.0 + SMALL_CONST,
            1.0 / (window_length)
        )[1:]
    else:
        decay_mask = 1.0

    # TODO fix this comment (SUMANTH)
    # Generate a mask is gradient perturbated is based on a past window
    _, _, _, curr_length, _ = past[0].shape

    if curr_length > window_length and window_length > 0:
        ones_key_val_shape = (
                tuple(past[0].shape[:-2])
                + tuple([window_length])
                + tuple(past[0].shape[-1:])
        )

        zeros_key_val_shape = (
                tuple(past[0].shape[:-2])
                + tuple([curr_length - window_length])
                + tuple(past[0].shape[-1:])
        )

        ones_mask = torch.ones(ones_key_val_shape)
        ones_mask = decay_mask * ones_mask.permute(0, 1, 2, 4, 3)
        ones_mask = ones_mask.permute(0, 1, 2, 4, 3)

        window_mask = torch.cat(
            (ones_mask, torch.zeros(zeros_key_val_shape)),
            dim=-2
        ).to(device)
    else:
        window_mask = torch.ones_like(past[0]).to(device)

    # accumulate perturbations for num_iterations
    loss_per_iter = []
    new_accumulated_hidden = None
    for i in range(num_iterations):
        if verbosity_level >= VERBOSE:
            print("Iteration ", i + 1)
        curr_perturbation = [
            to_var(torch.from_numpy(p_), requires_grad=True, device=device)
            for p_ in grad_accumulator
        ]

        # Compute hidden using perturbed past
        perturbed_past = list(map(add, past, curr_perturbation))
        _, _, _, curr_length, _ = curr_perturbation[0].shape
        all_logits, _, all_hidden = model(last, past_key_values=perturbed_past)
        hidden = all_hidden[-1]
        new_accumulated_hidden = accumulated_hidden + torch.sum(
            hidden,
            dim=1
        ).detach()
        # TODO: Check the layer-norm consistency of this with trained discriminator (Sumanth)
        logits = all_logits[:, -1, :]
        probs = F.softmax(logits, dim=-1)

        loss = 0.0
        loss_list = []
        if loss_type == PPLM_BOW or loss_type == PPLM_BOW_DISCRIM:
            for one_hot_bow in one_hot_bows_vectors:
                bow_logits = torch.mm(probs, torch.t(one_hot_bow))
                bow_loss = -torch.log(torch.sum(bow_logits))
                loss += bow_loss
                loss_list.append(bow_loss)
            if verbosity_level >= VERY_VERBOSE:
                print(" pplm_bow_loss:", loss.data.cpu().numpy())

        if loss_type == PPLM_DISCRIM or loss_type == PPLM_BOW_DISCRIM:
            ce_loss = torch.nn.CrossEntropyLoss()
            # TODO why we need to do this assignment and not just using unpert_past? (Sumanth)
            curr_unpert_past = unpert_past
            curr_probs = torch.unsqueeze(probs, dim=1)
            wte = model.resize_token_embeddings()
            for _ in range(horizon_length):
                inputs_embeds = torch.matmul(curr_probs, wte.weight.data)
                _, curr_unpert_past, curr_all_hidden = model(
                    past_key_values=curr_unpert_past,
                    inputs_embeds=inputs_embeds
                )
                curr_hidden = curr_all_hidden[-1]
                new_accumulated_hidden = new_accumulated_hidden + torch.sum(
                    curr_hidden, dim=1)

            prediction = classifier(new_accumulated_hidden /
                                    (curr_length + 1 + horizon_length))

            label = torch.tensor(prediction.shape[0] * [class_label],
                                 device=device,
                                 dtype=torch.long)
            discrim_loss = ce_loss(prediction, label)
            if verbosity_level >= VERY_VERBOSE:
                print(" pplm_discrim_loss:", discrim_loss.data.cpu().numpy())
            loss += discrim_loss
            loss_list.append(discrim_loss)

        kl_loss = 0.0
        if kl_scale > 0.0:
            unpert_probs = F.softmax(unpert_logits[:, -1, :], dim=-1)
            unpert_probs = (
                    unpert_probs + SMALL_CONST *
                    (unpert_probs <= SMALL_CONST).float().to(device).detach()
            )
            correction = SMALL_CONST * (probs <= SMALL_CONST).float().to(
                device).detach()
            corrected_probs = probs + correction.detach()
            kl_loss = kl_scale * (
                (corrected_probs * (corrected_probs / unpert_probs).log()).sum()
            )
            if verbosity_level >= VERY_VERBOSE:
                print(' kl_loss', kl_loss.data.cpu().numpy())
            loss += kl_loss

        loss_per_iter.append(loss.data.cpu().numpy())
        if verbosity_level >= VERBOSE:
            print(' pplm_loss', (loss - kl_loss).data.cpu().numpy())

        # compute gradients
        loss.backward()

        # calculate gradient norms
        if grad_norms is not None and loss_type == PPLM_BOW:
            grad_norms = [
                torch.max(grad_norms[index], torch.norm(p_.grad * window_mask))
                for index, p_ in enumerate(curr_perturbation)
            ]
        else:
            grad_norms = [
                (torch.norm(p_.grad * window_mask) + SMALL_CONST)
                for index, p_ in enumerate(curr_perturbation)
            ]

        # normalize gradients
        grad = [
            -stepsize *
            (p_.grad * window_mask / grad_norms[
                index] ** gamma).data.cpu().numpy()
            for index, p_ in enumerate(curr_perturbation)
        ]

        # accumulate gradient
        grad_accumulator = list(map(add, grad, grad_accumulator))

        # reset gradients, just to make sure
        for p_ in curr_perturbation:
            p_.grad.data.zero_()

        # removing past from the graph
        new_past = []
        for p_ in past:
            new_past.append(p_.detach())
        past = new_past

    # apply the accumulated perturbations to the past
    grad_accumulator = [
        to_var(torch.from_numpy(p_), requires_grad=True, device=device)
        for p_ in grad_accumulator
    ]
    pert_past = list(map(add, past, grad_accumulator))

    return pert_past, new_accumulated_hidden, grad_norms, loss_per_iter


def get_classifier(
        name: Optional[str],
        class_label: Union[str, int],
        device: str,
        verbosity_level: int = REGULAR,
        fp: str = None,
        is_deep: bool= False,
        is_deeper: bool=False,
) -> Tuple[Optional[ClassificationHead], Optional[int]]:
    if name is None:
        return None, None

    params = DISCRIMINATOR_MODELS_PARAMS[name]
    classifier = ClassificationHead(
        class_size=params['class_size'],
        embed_size=params['embed_size'],
        is_deep=is_deep,
        is_deeper=is_deeper
    ).to(device)
    if "url" in params:
        resolved_archive_file = cached_path(params["url"])
    elif "path" in params:
        resolved_archive_file = params["path"]
    elif fp != None:
        resolved_archive_file = fp
    else:
        raise ValueError("Either url or path have to be specified "
                         "in the discriminator model parameters")
    classifier.load_state_dict(
        torch.load(resolved_archive_file, map_location=device))
    classifier.eval()

    if isinstance(class_label, str):
        if class_label in params["class_vocab"]:
            label_id = params["class_vocab"][class_label]
        else:
            label_id = params["default_class"]
            if verbosity_level >= REGULAR:
                print("class_label {} not in class_vocab".format(class_label))
                print("available values are: {}".format(params["class_vocab"]))
                print("using default class {}".format(label_id))

    elif isinstance(class_label, int):
        if class_label in set(params["class_vocab"].values()):
            label_id = class_label
        else:
            label_id = params["default_class"]
            if verbosity_level >= REGULAR:
                print("class_label {} not in class_vocab".format(class_label))
                print("available values are: {}".format(params["class_vocab"]))
                print("using default class {}".format(label_id))

    else:
        label_id = params["default_class"]

    return classifier, label_id


def get_bag_of_words_indices(bag_of_words_ids_or_paths: List[str], tokenizer) -> \
        List[List[List[int]]]:
    bow_indices = []
    for id_or_path in bag_of_words_ids_or_paths:
        if id_or_path in BAG_OF_WORDS_ARCHIVE_MAP:
            filepath = cached_path(BAG_OF_WORDS_ARCHIVE_MAP[id_or_path])
        else:
            filepath = id_or_path
        with open(filepath, "r") as f:
            words = f.read().strip().split("\n")
        bow_indices.append(
            [tokenizer.encode(word.strip(),
                              add_prefix_space=True,
                              add_special_tokens=False)
             for word in words])
    return bow_indices


def build_bows_one_hot_vectors(bow_indices, tokenizer, device='cuda'):
    if bow_indices is None:
        return None

    one_hot_bows_vectors = []
    for single_bow in bow_indices:
        single_bow = list(filter(lambda x: len(x) <= 1, single_bow))
        single_bow = torch.tensor(single_bow).to(device)
        num_words = single_bow.shape[0]
        one_hot_bow = torch.zeros(num_words, tokenizer.vocab_size).to(device)
        one_hot_bow.scatter_(1, single_bow, 1)
        one_hot_bows_vectors.append(one_hot_bow)
    return one_hot_bows_vectors


def full_text_generation(
        model,
        tokenizer,
        context=None,
        num_samples=1,
        device="cuda",
        bag_of_words=None,
        discrim=None,
        class_label=None,
        length=100,
        stepsize=0.02,
        temperature=1.0,
        top_k=10,
        sample=True,
        num_iterations=3,
        grad_length=10000,
        horizon_length=1,
        window_length=0,
        decay=False,
        gamma=1.5,
        gm_scale=0.9,
        kl_scale=0.01,
        verbosity_level=REGULAR,
        fp=None,
        is_deep=False,
        is_deeper=False,
        stop_eot=False,
        **kwargs
):
    classifier, class_id = get_classifier(
        discrim,
        class_label,
        device,
        REGULAR,
        fp,
        is_deep,
        is_deeper
    )

    bow_indices = []
    if bag_of_words:
        bow_indices = get_bag_of_words_indices(bag_of_words.split(";"),
                                               tokenizer)

    if bag_of_words and classifier:
        loss_type = PPLM_BOW_DISCRIM
        if verbosity_level >= REGULAR:
            print("Both PPLM-BoW and PPLM-Discrim are on. "
                  "This is not optimized.")

    elif bag_of_words:
        loss_type = PPLM_BOW
        if verbosity_level >= REGULAR:
            print("Using PPLM-BoW")

    elif classifier is not None:
        loss_type = PPLM_DISCRIM
        if verbosity_level >= REGULAR:
            print("Using PPLM-Discrim")

    else:
        raise Exception("Specify either a bag of words or a discriminator")

    unpert_gen_tok_text, _, _, _ = generate_text_pplm(
        model=model,
        tokenizer=tokenizer,
        context=context,
        device=device,
        length=length,
        sample=sample,
        perturb=False,
        verbosity_level=verbosity_level,
        stop_eot=stop_eot
    )
    if device == 'cuda':
        torch.cuda.empty_cache()

    pert_gen_tok_texts = []
    discrim_losses = []
    losses_in_time = []
    perplexities = []

    for i in range(num_samples):
        pert_gen_tok_text, discrim_loss, loss_in_time, perplexity = generate_text_pplm(
            model=model,
            tokenizer=tokenizer,
            context=context,
            device=device,
            perturb=True,
            bow_indices=bow_indices,
            classifier=classifier,
            class_label=class_id,
            loss_type=loss_type,
            length=length,
            stepsize=stepsize,
            temperature=temperature,
            top_k=top_k,
            sample=sample,
            num_iterations=num_iterations,
            grad_length=grad_length,
            horizon_length=horizon_length,
            window_length=window_length,
            decay=decay,
            gamma=gamma,
            gm_scale=gm_scale,
            kl_scale=kl_scale,
            verbosity_level=verbosity_level,
            stop_eot=stop_eot
        )
        pert_gen_tok_texts.append(pert_gen_tok_text)
        if classifier is not None:
            discrim_losses.append(discrim_loss.data.cpu().numpy())
        losses_in_time.append(loss_in_time)
        perplexities.append(perplexity)

    if device == 'cuda':
        torch.cuda.empty_cache()

    return unpert_gen_tok_text, pert_gen_tok_texts, discrim_losses, losses_in_time, perplexities


def generate_text_pplm(
        model,
        tokenizer,
        context=None,
        past=None,
        device="cuda",
        perturb=True,
        bow_indices=None,
        classifier=None,
        class_label=None,
        loss_type=0,
        length=100,
        stepsize=0.02,
        temperature=1.0,
        top_k=10,
        sample=True,
        num_iterations=3,
        grad_length=10000,
        horizon_length=1,
        window_length=0,
        decay=False,
        gamma=1.5,
        gm_scale=0.9,
        kl_scale=0.01,
        verbosity_level=REGULAR,
        stop_eot=False
):
    output_so_far = None
    if context:
        context_t = torch.tensor(context, device=device, dtype=torch.long)
        while len(context_t.shape) < 2:
            context_t = context_t.unsqueeze(0)
        output_so_far = context_t

    # collect one hot vectors for bags of words
    one_hot_bows_vectors = build_bows_one_hot_vectors(bow_indices, tokenizer,
                                                      device)

    grad_norms = None
    last = None
    unpert_discrim_loss = 0
    loss_in_time = []

    if verbosity_level >= VERBOSE:
        range_func = trange(length, ascii=True)
    else:
        range_func = range(length)
    
    pert_total_prob = 1
    pert_times = 0
    last_reps = torch.ones(50257)
    last_reps = last_reps.to(device)
    for i in range_func:
        # Get past/probs for current output, except for last word
        # Note that GPT takes 2 inputs: past + current_token
        
        # run model forward to obtain unperturbed
        if past is None and output_so_far is not None:
            last = output_so_far[:, -1:]
            if output_so_far.shape[1] > 1:
                _, past, _ = model(output_so_far[:, :-1])

        unpert_logits, unpert_past, unpert_all_hidden = model(output_so_far)
        unpert_last_hidden = unpert_all_hidden[-1]

        # check if we are abowe grad max length
        if i >= grad_length:
            current_stepsize = stepsize * 0
        else:
            current_stepsize = stepsize

        # modify the past if necessary
        if not perturb or num_iterations == 0:
            pert_past = past

        else:
            accumulated_hidden = unpert_last_hidden[:, :-1, :]
            accumulated_hidden = torch.sum(accumulated_hidden, dim=1)

            if past is not None:
                pert_past, _, grad_norms, loss_this_iter = perturb_past(
                    past,
                    model,
                    last,
                    unpert_past=unpert_past,
                    unpert_logits=unpert_logits,
                    accumulated_hidden=accumulated_hidden,
                    grad_norms=grad_norms,
                    stepsize=current_stepsize,
                    one_hot_bows_vectors=one_hot_bows_vectors,
                    classifier=classifier,
                    class_label=class_label,
                    loss_type=loss_type,
                    num_iterations=num_iterations,
                    horizon_length=horizon_length,
                    window_length=window_length,
                    decay=decay,
                    gamma=gamma,
                    kl_scale=kl_scale,
                    device=device,
                    verbosity_level=verbosity_level
                )
                loss_in_time.append(loss_this_iter)
            else:
                pert_past = past

        pert_logits, past, pert_all_hidden = model(last, past_key_values=pert_past)
        pert_logits = pert_logits[:, -1, :] / temperature  # + SMALL_CONST
        pert_probs = F.softmax(pert_logits, dim=-1)

        if classifier is not None:
            ce_loss = torch.nn.CrossEntropyLoss()
            prediction = classifier(torch.mean(unpert_last_hidden, dim=1))
            label = torch.tensor([class_label], device=device,
                                 dtype=torch.long)
            unpert_discrim_loss = ce_loss(prediction, label)
            if verbosity_level >= VERBOSE:
                print(
                    "unperturbed discrim loss",
                    unpert_discrim_loss.data.cpu().numpy()
                )
        else:
            unpert_discrim_loss = 0

        # Fuse the modified model and original model
        if perturb:

            unpert_probs = F.softmax(unpert_logits[:, -1, :], dim=-1)

            pert_probs = ((pert_probs ** gm_scale) * (
                    unpert_probs ** (1 - gm_scale)))  # + SMALL_CONST
            if i < 2:
                pert_probs = top_k_filter(pert_probs, k=max(2, top_k), probs=True)  # + SMALL_CONST
                if i == 0: pert_probs[0][50256] = 0
                if i == 1: 
                    tmp = pert_probs[0][50256]
                    pert_probs[0][50256] = 0
                    pert_probs[0][50256] = min(torch.max(pert_probs[0]), tmp)
            else:
                pert_probs = top_k_filter(pert_probs, k=top_k, probs=True)  # + SMALL_CONST
            pert_probs = torch.div(pert_probs, last_reps)
            # rescale
            if torch.sum(pert_probs) <= 1:
                pert_probs = pert_probs / torch.sum(pert_probs)
        else:
            pert_logits = top_k_filter(pert_logits, k=top_k)  # + SMALL_CONST
            pert_probs = F.softmax(pert_logits, dim=-1)

        # sample or greedy
        if sample:
            last = torch.multinomial(pert_probs, num_samples=1)
            pert_total_prob = pert_total_prob * pert_probs[0][last[0][0]]
        else:
            _, last = torch.topk(pert_probs, k=1, dim=-1)
        last_reps[last[0][0]] = last_reps[last[0][0]] * 8
        # update context/output_so_far appending the new token
        output_so_far = (
            last if output_so_far is None
            else torch.cat((output_so_far, last), dim=1)
        )
        if verbosity_level >= REGULAR:
            print(tokenizer.decode(output_so_far.tolist()[0]))
        pert_times += 1
        if last[0][0] ==  50256 and stop_eot: 
          break
    perplexity = (1/pert_total_prob)**(1/pert_times)
    return output_so_far, unpert_discrim_loss, loss_in_time, perplexity


def set_generic_model_params(discrim_weights, discrim_meta):
    if discrim_weights is None:
        raise ValueError('When using a generic discriminator, '
                         'discrim_weights need to be specified')
    if discrim_meta is None:
        raise ValueError('When using a generic discriminator, '
                         'discrim_meta need to be specified')

    with open(discrim_meta, 'r') as discrim_meta_file:
        meta = json.load(discrim_meta_file)
    meta['path'] = discrim_weights
    DISCRIMINATOR_MODELS_PARAMS['generic'] = meta


pretrained_model="microsoft/DialoGPT-large"
cond_text=""
uncond=False
num_samples=1
bag_of_words=None
discrim="3_PerSoothe_lrg"
discrim_weights=None
discrim_meta=None
class_label=0
length=100
stepsize=0.99
temperature=1.0
top_k=2
sample=True
num_iterations=10
grad_length=10000
horizon_length=1
window_length=0
decay=False
gamma=1.0
gm_scale=0.95
kl_scale=0.01
seed=0
no_cuda=False
colorama=False
verbosity="quiet"
fp="./paper_code/discrim_models/persoothe_classifier.pt" #"/content/drive/Shareddrives/COS_IW04_ZL/COSIW04/Discriminators/3_class_lrggpt_fit_deeper_2/3_PerSoothe_classifier_head_epoch_8.pt"
model_fp="./paper_code/discrim_models/persoothe_encoder.pt" #None 
calc_perplexity=False
is_deep=False
is_deeper=True
stop_eot=True

# set Random seed
torch.manual_seed(seed)
np.random.seed(seed)

# set verbosiry
verbosity_level = VERBOSITY_LEVELS.get(verbosity.lower(), REGULAR)

# set the device
device = "cuda" if torch.cuda.is_available() and not no_cuda else "cpu"

if discrim == 'generic':
    set_generic_model_params(discrim_weights, discrim_meta)

if discrim is not None:
    discriminator_pretrained_model = DISCRIMINATOR_MODELS_PARAMS[discrim][
        "pretrained_model"
    ]
    if pretrained_model != discriminator_pretrained_model:
        pretrained_model = discriminator_pretrained_model
        if verbosity_level >= REGULAR:
            print("discrim = {}, pretrained_model set "
            "to discriminator's = {}".format(discrim, pretrained_model))

# load pretrained model
model = GPT2LMHeadModel.from_pretrained(
    pretrained_model,
    output_hidden_states=True
)
if model_fp != None and model_fp != "": 
    model.load_state_dict(torch.load(model_fp, map_location=device))
model.to(device)
model.eval()

# load tokenizer
tokenizer = GPT2Tokenizer.from_pretrained(pretrained_model)

# Freeze GPT-2 weights
for param in model.parameters():
    param.requires_grad = False

eot_token = "<|endoftext|>"

def get_reply(response, username = None, histories = {}, in_stepsize = 0.99, in_horizon_length = 1, in_num_iterations = 10, in_top_k = 2):
    if username == None or username == "": return "<div class='chatbot'>Enter a username</div>", histories
    stepsize = in_stepsize
    horizon_length = int(in_horizon_length)
    num_iterations = int(in_num_iterations)
    top_k = int(in_top_k)
    if response.endswith(("bye", "Bye", "bye.", "Bye.", "bye!", "Bye!")):
        histories[username] = None
        return "<div class='chatbot'>Chatbot restarted</div>", histories
    history = histories.get(username, None)
    convo_hist = (history if history != None else "How are you?<|endoftext|>") + response + eot_token
    # figure out conditioning text
    tokenized_cond_text = tokenizer.encode(
            eot_token + convo_hist,
            add_special_tokens=False
    )
    # generate perturbed texts

    # full_text_generation returns:
    # unpert_gen_tok_text, pert_gen_tok_texts, discrim_losses, losses_in_time
    _, pert_gen_tok_texts, _, _, _ = full_text_generation(
        model=model,
        tokenizer=tokenizer,
        context=tokenized_cond_text,
        device=device,
        num_samples=1,
        bag_of_words=bag_of_words,
        discrim=discrim,
        class_label=class_label,
        length=length,
        stepsize=stepsize,
        temperature=temperature,
        top_k=top_k,
        sample=sample,
        num_iterations=num_iterations,
        grad_length=grad_length,
        horizon_length=horizon_length,
        window_length=window_length,
        decay=decay,
        gamma=gamma,
        gm_scale=gm_scale,
        kl_scale=kl_scale,
        verbosity_level=verbosity_level,
        fp=fp,
        is_deep=is_deep,
        is_deeper=is_deeper,
        stop_eot=stop_eot
    )

    # iterate through the perturbed texts
    for i, pert_gen_tok_text in enumerate(pert_gen_tok_texts):
        try:
            pert_gen_text = tokenizer.decode(pert_gen_tok_text.tolist()[0])
            convo_hist_split = pert_gen_text.split(eot_token)
            html = "<div class='chatbot'>"
            for m, msg in enumerate(convo_hist_split[1:-1]):
                cls = "user" if m%2 == 0 else "bot"
                html += "<div class='msg {}'> {}</div>".format(cls, msg)
            html += "</div>"

            if len(convo_hist_split) > 4: convo_hist_split = convo_hist_split[-4:]
            convo_hist = eot_token.join(convo_hist_split)

        except:
            histories[username] = None
            return "<div class='chatbot'>Error occured, chatbot restarted</div>", histories
    histories[username] = convo_hist
    return html, histories

css = """
.chatbox {display:flex;flex-direction:column}
.msg {padding:4px;margin-bottom:4px;border-radius:4px;width:80%}
.msg.user {background-color:cornflowerblue;color:white}
.msg.bot {background-color:lightgray;align-self:self-end}
.footer {display:none !important}
"""

gr.Interface(fn=get_reply,
             theme="default",
             inputs=[gr.inputs.Textbox(placeholder="How are you?"), 
                    gr.inputs.Textbox(label="Username"),
                    "state"],
             outputs=["html", "state"],
             css=css).launch(debug=True, enable_queue=True)