add solutions for logit exercise

4_logit/solutions/logit_parallel.py

+"""
+Data-parallel logistic regression
+"""
+import argparse
+import time
+from typing import Union
+
+import h5py
+from mpi4py import MPI
+import numpy as np
+
+np.random.seed(842424)  # Fix random seed for reproducibility.
+
+
+def sigmoid(z: Union[float, np.ndarray]) -> Union[float, np.ndarray]:
+    """
+    Compute sigmoid.
+
+    Parameters
+    ----------
+    z : float
+        The input for the sigmoid function.
+
+    Returns
+    ----------
+    float
+        The input's sigmoid function value.
+    """
+    return 1.0 / (1.0 + np.exp(-z))
+
+
+def lr_predict(w: np.ndarray, x: np.ndarray) -> np.ndarray:
+    """
+    Return prediction of logit model for data x using model weights w.
+
+    Parameters
+    ----------
+    x : np.ndarray[float]
+        The dataset (after bias trick), shape = [n_samples, n_features +1].
+        The 0th input should be 1.0 to take the bias into account in a simple dot product.
+    w : np.ndarray[float]
+        The parameters, i.e., weights to be learned (after bias trick), shape = [n_features + 1, ].
+        There is one weight for every input dimension plus a bias.
+
+    Returns
+    -------
+    np.ndarray[float]
+        The predicted activations of the logit model for the input dataset, shape = [n_samples, ],
+        i.e., the sigmoid of the dot product of the weights and the input data.
+    """
+    return sigmoid(x @ w)
+
+
+def mse(y_est: np.ndarray, y: np.ndarray) -> np.ndarray:
+    """
+    Compute mean-square-error loss.
+
+    Parameters
+    ----------
+    y_est : np.ndarray[float]
+        The predictions, shape = [n_samples, ].
+    y : np.ndarray[float]
+        The ground-truth labels, shape = [n_samples, ].
+
+    Returns
+    ----------
+    np.ndarray[float]
+        MSE loss
+    """
+    return (
+        (1.0 / y.shape[0]) * (y - y_est).T @ (y - y_est)
+    )  # Return MSE loss for considered batch.
+
+
+def lr_loss(
+    w: np.ndarray, x: np.ndarray, y: np.ndarray
+) -> tuple[np.ndarray, np.ndarray]:
+    """
+    Return the loss and the gradient with respect to the weights.
+
+    Parameters
+    ----------
+    w : np.ndarray[float]
+        The model's weights to be learned, where weights[0] is the bias.
+    x : np.ndarray[float]
+        The input data of shape [N x D+1], 0th element of each sample is assumed to be 1 (bias trick).
+    y : np.ndarray[float]
+        The ground-truth labels of shape [N,].
+
+    Returns
+    -------
+    np.ndarray[float]
+        The scalar mean-square-error loss for the input batch of samples.
+    np.ndarray[float]
+        The gradient of the loss with respect to the weights for the batch.
+    """
+    y_est = lr_predict(w, x)  # Compute logit prediction for all samples in batch.
+    loss = mse(y_est, y)  # Compute MSE loss over all samples in batch.
+    # Compute gradient vector of loss w.r.t. weights.
+    gradient = (
+        (-2.0 / y.shape[0]) * ((y - y_est) * y_est * y_est * np.exp(-x @ w)).T @ x
+    )
+    return loss, gradient
+
+
+def lr_train(
+    w: np.ndarray,
+    x: np.ndarray,
+    y: np.ndarray,
+    comm: MPI.Comm = MPI.COMM_WORLD,
+    epochs: int = 100,
+    eta: float = 0.001,
+    b: int = 10,
+) -> tuple[np.ndarray, np.ndarray, np.ndarray, float]:
+    """
+    Train the model, i.e., update the weights following the negative gradient until the model converges.
+
+    Parameters
+    ----------
+    w : np.ndarray[float]
+        The model weights to be learned, where weights[0] is the bias.
+    x : np.ndarray[float]
+        The input data of shape [N x D+1], where each sample's 0th element is assumed to be 1 for bias trick.
+    y : np.ndarray[float]
+        The ground-truth labels of shape [N,].
+    epochs : int
+        The number of epochs to be trained.
+    eta : float
+        The learning rate.
+    b : int
+        The batch size.
+
+    Returns
+    -------
+    np.ndarray[float]
+        The trained weights.
+    np.ndarray[float]
+        The history array with each epoch's loss.
+    np.ndarray[float]
+        The history array with each epoch's accuracy.
+    float
+        The average training time per epoch.
+    """
+    size, rank = comm.size, comm.rank
+
+    # Apply bias trick.
+    n_samples = y.shape[0]  # Determine number of samples.
+    n_batches = n_samples // b  # Determine number of full batches in data (drop last).
+    print(f"Rank {rank}/{size}: Data is divided into {n_batches} batches.")
+    loss_history = np.zeros(epochs)
+    acc_history = np.zeros(epochs)
+    training_time_per_epoch = 0.0  # Initiate training time per epoch.
+
+    for epoch in range(epochs):  # Loop over epochs.
+        # The number of epochs is a hyperparameter of gradient descent
+        # that controls the number of complete passes through the training dataset.
+        # The batch size is a hyperparameter of gradient descent
+        # that controls the number of training samples to work through before the
+        # model’s internal parameters are updated.
+
+        loss_sum = 0.0  # Initiate loss for each epoch.
+        accuracy = 0.0  # Initiate accuracy for each epoch.
+
+        start = time.perf_counter()
+
+        for nb in range(n_batches):
+            x_ = x[nb * b : (nb + 1) * b]
+            y_ = y[nb * b : (nb + 1) * b]
+            loss, gradient = lr_loss(w, x_, y_)
+            loss_sum += loss
+
+            corr = np.sum((lr_predict(w, x_) + 0.5).astype(int) == y_)
+            accuracy += corr
+            gradient_global = np.zeros_like(gradient)
+            comm.Allreduce(gradient, gradient_global, op=MPI.SUM)
+            gradient_global /= size
+            w -= eta * gradient_global
+
+        end = time.perf_counter()
+
+        # Calculate loss + accuracy after each epoch.
+        loss_sum /= n_batches
+        accuracy /= n_samples
+        accuracy *= 100
+
+        loss_sum_global = comm.allreduce(loss_sum, op=MPI.SUM) / size
+        accuracy_global = comm.allreduce(accuracy, op=MPI.SUM) / size
+
+        loss_history[epoch] = loss_sum_global
+        acc_history[epoch] = accuracy_global
+        training_time_per_epoch += end - start
+
+        # Print every tenth epoch the training status.
+        if rank == 0:
+            if epoch % 10 == 0:
+                print(
+                    f"Epoch: {epoch}, Loss: {loss_sum_global}, Accuracy: {accuracy_global}"
+                )
+    training_time_per_epoch /= epochs
+    training_time_per_epoch_global = (
+        comm.allreduce(training_time_per_epoch, op=MPI.SUM) / size
+    )
+    return w, loss_history, acc_history, training_time_per_epoch_global
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(prog="Logit")
+    parser.add_argument(
+        "--epochs",
+        type=int,
+        default=100,
+        help="The number of epochs to train.",
+    )
+
+    parser.add_argument(
+        "--batch_size",
+        type=int,
+        default=10,
+        help="The batch size.",
+    )
+
+    args = parser.parse_args()
+    comm = MPI.COMM_WORLD  # Set up communicator.
+    size, rank = comm.size, comm.rank
+
+    if rank == 0:
+        print(
+            "################################\n"
+            "# Parallel Logistic Regression #\n"
+            "################################"
+        )
+        print(
+            f"We train for {args.epochs} epochs with an effective batch size of {args.batch_size}."
+        )
+
+    path = "/pfs/work7/workspace/scratch/ku4408-VL-ScalableAI/data/logit_data_n100000_d2.h5"
+
+    with h5py.File(path, "r") as f:  # Load data in sample-parallel fashion.
+        chunk = int(f["data"].shape[0] / size)
+        if rank == size - 1:
+            data = np.array(f["data"][rank * chunk :])
+            labels = np.array(f["labels"][rank * chunk :])
+        else:
+            data = np.array(f["data"][rank * chunk : (rank + 1) * chunk])
+            labels = np.array(f["labels"][rank * chunk : (rank + 1) * chunk])
+
+    print(
+        f"Rank {rank}/{size}: Local data has {data.shape[0]} samples with {data.shape[1]} features and "
+        f"{labels.shape[0]} labels.\n0th elements are: {data[0]}\n{labels[0]}"
+    )
+
+    # Bias trick: Prepend data with 1's for additional bias dimension.
+    ones = np.ones(
+        (
+            data.shape[0],
+            1,
+        )
+    )
+    data_bt = np.hstack([ones, data])
+
+    # Initialize model parameters randomly.
+    # After bias trick, weights have shape [n_features+1, ]
+    if rank == 0:
+        weights = np.random.rand(data_bt.shape[1])
+    else:
+        weights = np.zeros(data_bt.shape[1])
+
+    # Broadcast weights from root to other processors.
+    comm.Bcast(weights, root=0)
+
+    b_local = args.batch_size // size  # Calculate local batch size.
+    print(f"Rank {rank}/{size}: Local batch size is {b_local}.")
+    # Train model.
+    (weights, loss_history, acc_history, training_time_per_epoch) = lr_train(
+        weights, data_bt, labels, b=b_local, epochs=args.epochs
+    )
+
+    if rank == 0:
+        print(
+            f"Final loss: {loss_history[-1]}, final accuracy: {acc_history[-1]}\n"
+            f"Average training time per epoch: {training_time_per_epoch} s"
+        )

4_logit/solutions/logit_serial.py

+import argparse
+import time
+from typing import Union, Tuple
+
+import h5py
+import numpy as np
+
+
+np.random.seed(842424)  # Fix random seed for reproducibility.
+
+
+def sigmoid(z: Union[float, np.ndarray]) -> Union[float, np.ndarray]:
+    """
+    Compute sigmoid.
+
+    Parameters
+    ----------
+    z : float
+        The input for the sigmoid function.
+
+    Returns
+    ----------
+    float
+        The input's sigmoid function value.
+    """
+    return 1.0 / (1.0 + np.exp(-z))
+
+
+def lr_predict(w: np.ndarray, x: np.ndarray) -> np.ndarray:
+    """
+    Return prediction of logit model for data x using model weights w.
+
+    Parameters
+    ----------
+    x : np.ndarray[float]
+        The dataset (after bias trick), shape = [n_samples, n_features +1].
+        The 0th input should be 1.0 to take the bias into account in a simple dot product.
+    w : np.ndarray[float]
+        The parameters, i.e., weights to be learned (after bias trick), shape = [n_features + 1, ].
+        There is one weight for every input dimension plus a bias.
+
+    Returns
+    -------
+    np.ndarray[float]
+        The predicted activations of the logit model for the input dataset, shape = [n_samples, ],
+        i.e., the sigmoid of the dot product of the weights and the input data.
+    """
+    return sigmoid(x @ w)
+
+
+def mse(y_est: np.ndarray, y: np.ndarray) -> np.ndarray:
+    """
+    Compute mean-square-error loss.
+
+    Parameters
+    ----------
+    y_est : np.ndarray[float]
+        The predictions, shape = [n_samples, ].
+    y : np.ndarray[float]
+        The ground-truth labels, shape = [n_samples, ].
+
+    Returns
+    ----------
+    np.ndarray[float]
+        MSE loss
+    """
+    return (
+        (1.0 / y.shape[0]) * (y - y_est).T @ (y - y_est)
+    )  # Return MSE loss for considered batch.
+
+
+def lr_loss(
+    w: np.ndarray, x: np.ndarray, y: np.ndarray
+) -> Tuple[np.ndarray, np.ndarray]:
+    """
+    Return the loss and the gradient with respect to the weights.
+
+    Parameters
+    ----------
+    w : np.ndarray[float]
+        The model's weights to be learned, where weights[0] is the bias.
+    x : np.ndarray[float]
+        The input data of shape [N x D+1], 0th element of each sample is assumed to be 1 (bias trick).
+    y : np.ndarray[float]
+        The ground-truth labels of shape [N,].
+
+    Returns
+    -------
+    np.ndarray[float]
+        The scalar mean-square-error loss for the input batch of samples.
+    np.ndarray[float]
+        The gradient of the loss with respect to the weights for the batch.
+    """
+    y_est = lr_predict(w, x)  # Compute logit prediction for all samples in batch.
+    loss = mse(y_est, y)  # Compute MSE loss over all samples in batch.
+    # Compute gradient vector of loss w.r.t. weights.
+    gradient = (
+        (-2.0 / y.shape[0]) * ((y - y_est) * y_est * y_est * np.exp(-x @ w)).T @ x
+    )
+    return loss, gradient
+
+
+def lr_train(
+    w: np.ndarray,
+    x: np.ndarray,
+    y: np.ndarray,
+    epochs: int = 100,
+    eta: float = 0.001,
+    b: int = 10,
+) -> Tuple[np.ndarray, np.ndarray, np.ndarray, float]:
+    """
+    Train the model, i.e., update the weights following the negative gradient until the model converges.
+
+    Parameters
+    ----------
+    w : np.ndarray[float]
+        The model weights to be learned, where weights[0] is the bias.
+    x : np.ndarray[float]
+        The input data of shape [N x D+1], where each sample's 0th element is assumed to be 1 for bias trick.
+    y : np.ndarray[float]
+        The ground-truth labels of shape [N,].
+    epochs : int
+        The number of epochs to be trained.
+    eta : float
+        The learning rate.
+    b : int
+        The batch size.
+
+    Returns
+    -------
+    np.ndarray[float]
+        The trained weights.
+    np.ndarray[float]
+        The history array with each epoch's loss.
+    np.ndarray[float]
+        The history array with each epoch's accuracy.
+    float
+        The average training time per epoch.
+    """
+    n_samples = y.shape[0]  # Determine number of samples in batch.
+    n_batches = n_samples // b  # Determine number of full batches in data (drop last).
+    print(f"Data is divided into {n_batches} batches.")
+    loss_history = np.zeros(epochs)
+    acc_history = np.zeros(epochs)
+    training_time_per_epoch = 0.0  # Initiate training time per epoch.
+
+    for epoch in range(epochs):  # Loop over epochs.
+        # The number of epochs is a hyperparameter of gradient descent
+        # that controls the number of complete passes through the training dataset.
+        # The batch size is a hyperparameter of gradient descent
+        # that controls the number of training samples to work through before the
+        # model’s internal parameters are updated.
+        loss_sum = 0.0  # Initiate loss for each epoch.
+        accuracy = 0.0  # Initiate accuracy for each epoch.
+
+        start = time.perf_counter()  # Start timer.
+
+        for nb in range(n_batches):
+            x_ = x[nb * b : (nb + 1) * b]
+            y_ = y[nb * b : (nb + 1) * b]
+            loss, gradient = lr_loss(w, x_, y_)
+            loss_sum += loss
+
+            corr = np.sum((lr_predict(w, x_) + 0.5).astype(int) == y_)
+            accuracy += corr
+            w -= eta * gradient
+
+        end = time.perf_counter()  # Stop timer.
+
+        # Calculate loss + accuracy after each epoch.
+        loss_sum /= n_batches
+        accuracy /= n_samples
+        accuracy *= 100
+
+        # Append loss + accuracy of current epoch to history arrays.
+        loss_history[epoch] = loss_sum
+        acc_history[epoch] = accuracy
+        training_time_per_epoch += end - start
+
+        # Print every tenth epoch the training status.
+        if epochs < 100:
+            mod = 5
+        elif 100 <= epochs < 1000:
+            mod = 10
+        elif 1000 <= epochs < 10000:
+            mod = 100
+        elif 10000 <= epochs < 100000:
+            mod = 1000
+        else:
+            mod = 10000
+        if epoch % mod == 0:
+            print(f"Epoch: {epoch}, Loss: {loss_sum}, Accuracy: {accuracy}")
+    training_time_per_epoch /= epochs
+    return w, loss_history, acc_history, training_time_per_epoch
+
+
+if __name__ == "__main__":
+    path = "/pfs/work7/workspace/scratch/ku4408-VL-ScalableAI/data/logit_data_n10000_d2.h5"
+    parser = argparse.ArgumentParser(prog="Logit")
+    parser.add_argument(
+        "--epochs",
+        type=int,
+        default=100,
+        help="The number of epochs to train.",
+    )
+
+    parser.add_argument(
+        "--batch_size",
+        type=int,
+        default=10,
+        help="The batch size.",
+    )
+
+    args = parser.parse_args()
+
+    with h5py.File(path, "r") as f:
+        data = np.array(f["data"])
+        labels = np.array(f["labels"])
+
+    print(
+        f"We have {data.shape[0]} samples with {data.shape[1]} features and {labels.shape[0]} labels."
+    )
+
+    # Bias trick: Prepend data with 1's for additional bias dimension.
+    ones = np.ones(
+        (
+            data.shape[0],
+            1,
+        )
+    )
+    data_bt = np.hstack([ones, data])
+    weights = np.random.rand(data_bt.shape[1])  # Initialize model parameters randomly.
+    weights, loss_history, acc_history, time_per_epoch = lr_train(
+        weights, data_bt, labels, epochs=args.epochs, b=args.batch_size
+    )
+    print(f"Final loss is {loss_history[-1]}, final accuracy is {acc_history[-1]}.")
+    print(f"Training time per epoch is {time_per_epoch} s.")
+

4_logit/solutions/submit_parallel.sh

+#!/bin/bash
+
+#SBATCH --job-name=logit_parallel          # Job name
+#SBATCH --partition=dev_multiple           # Queue for the resource allocation
+#SBATCH --nodes=4			   # Number of nodes
+#SBATCH --time=5:00                        # Wall-clock time limit  
+#SBATCH --cpus-per-task=40                 # Number of CPUs required per MPI task
+#SBATCH --ntasks-per-node=1                # Maximum count of tasks per node
+#SBATCH --mail-type=ALL                    # Notify user by email when certain event types occur.
+
+export OMP_NUM_THREADS=40
+export VENVDIR=<path/to/your/venv>         # Export path to your virtual environment.
+export PYDIR=<path/to/your/python/script>  # Export path to directory containing Python script.
+
+# Set up modules.
+module purge                               # Unload all currently loaded modules.
+module load compiler/gnu/13.3              # Load required modules.
+module load mpi/openmpi/4.1
+module load devel/cuda/12.4
+module load lib/hdf5/1.14.4-gnu-13.3-openmpi-4.1
+
+source ${VENVDIR}/bin/activate # Activate your virtual environment.
+mpirun python ${PYDIR}/logit_parallel.py --epochs 100 --batch_size 100

4_logit/solutions/submit_serial.sh

+#!/bin/bash
+
+#SBATCH --job-name=logit_serial            # Job name
+#SBATCH --partition=dev_single             # Queue for the resource allocation.
+#SBATCH --time=5:00                        # Wall-clock time limit  
+#SBATCH --cpus-per-task=40                 # Number of CPUs required per MPI task
+#SBATCH --ntasks-per-node=1                # Maximum count of tasks per node
+#SBATCH --mail-type=ALL                    # Notify user by email when certain event types occur.
+
+export OMP_NUM_THREADS=40
+export VENVDIR=<path/to/your/venv>         # Export path to your virtual environment.
+export PYDIR=<path/to/your/python/script>  # Export path to directory containing Python script.
+
+# Set up modules.
+module purge                               # Unload all currently loaded modules.
+module load compiler/gnu/13.3              # Load required modules.
+module load mpi/openmpi/4.1
+module load devel/cuda/12.4
+module load lib/hdf5/1.14.4-gnu-13.3-openmpi-4.1
+
+source ${VENVDIR}/bin/activate # Activate your virtual environment.
+
+python ${PYDIR}/logit_serial.py --epochs 100 --batch_size 10