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de_loss_vec = dfdt(nn, t) - R * t * (1 - t)

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final_loss = \
    # average over all the colocation points
    de_loss_vec.pow(2).mean() + \
    # simply square the boundary contribution which is a single value
    boundary_loss ** 2

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# create a 5-layers PINN with 5 neurons per layer
nn_approximator = PINN(5, 5)

# hyperparameters and optimizer
max_epochs = 10_000
learning_rate = 0.01
optimizer = torch.optim.Adam(nn_approximator.parameters(), lr=learning_rate)

# optimization loop
for epoch in range(max_epochs):

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#!/bin/bash

# select a list of commits starting from head and put the in a file
# this is useful when selecting a set of commits to cherry-pick
git log --oneline | head -25 | tac | awk '{print $1}' | sed ':label1 ; N ; $! b label1 ; s/\n/\ /g' > commits.txt

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import torch
import torch.nn as nn

R = 1.0  # rate of maximum population growth parameterizing the equation
X_BOUNDARY = 0.0  # boundary condition coordinate
F_BOUNDARY = 0.5  # boundary condition value


def loss_fn(params: torch.Tensor, x: torch.Tensor) -> torch.Tensor:

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from functorch import make_functional, grad, vmap

# create the PINN model and make it functional using functorch utilities
model = NNApproximator()
fmodel, params = make_functional(model)

def f(x: torch.Tensor, params: torch.Tensor) -> torch.Tensor:
    # only a single element is supported thus unsqueeze must be applied
    # for batching multiple inputs, `vmap` must be used as below
    x_ = x.unsqueeze(0)

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# choose the configuration
batch_size = 30  # number of colocation points sampled in the domain
num_iter = 100  # maximum number of iterations
learning_rate = 1e-1  # learning rate
domain = (-5.0, 5.0)  # logistic equation domain

# choose optimizer with functional API using functorch
optimizer = torchopt.FuncOptimizer(torchopt.adam(lr=learning_rate))

# train the model

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class SimpleNN(nn.Module):
    def __init__(
        self,
        num_hidden: int = 1,
        dim_hidden: int = 1,
        act: nn.Module = nn.Tanh(),
    ) -> None:
        """Basic neural network with linear layers and non-linear activation function

        Args:

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import numpy as np
import torch
from torch import nn
from torch import Tensor
from torch.func import functional_call
import torchopt
import matplotlib.pyplot as plt


class SimpleNN(nn.Module):

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type Message struct {
	Sender   string `json:"sender"`
	Receiver string `json:"receiver"`
	Body     string `json:"body"`
	Time     string `json:"time"`
}

type User struct {
	isOnline bool
	msgCh    chan Message