Machine Learning and Deep Learning Algorithm Trading, Autoregressive CNN with 1D Convolution

Algorithmic trading in today’s financial markets is rapidly evolving, with machine learning and deep learning techniques receiving increasing attention. In particular, one-dimensional convolutional neural networks (1D CNNs) are establishing themselves as a powerful tool suited for time series data. This article will take a detailed look at the process of developing a trading strategy using autoregressive CNN with 1D convolution.

1. Overview of Machine Learning and Deep Learning

Machine learning is a set of algorithms that learn from data to make predictions and decisions. In contrast, deep learning is a method within machine learning that learns complex structures and patterns using artificial neural networks. These two techniques can be utilized in the financial market for various applications such as price prediction, trading signal generation, and risk management.

1.1 Differences Between Machine Learning and Deep Learning

Machine learning generally excels at processing structured data and operates in high-dimensional feature spaces. On the other hand, deep learning excels at processing unstructured data such as images and text. 1D CNN is optimized for time series data, effectively handling information such as stock prices and trading volumes.

1.2 Overview of Convolutional Neural Networks (CNN)

CNN is a network architecture widely used for image classification and recognition. The main components of a CNN include convolutional layers, activation layers, and pooling layers. The 1D CNN is a variation of this structure adapted to temporal characteristics, primarily used for extracting patterns from time series data.

2. Autoregressive Models

Autoregressive models (AR) are statistical methods that predict current values based on past observations. They are primarily used in time series data analysis and typically predict future values based on mathematical modeling.

2.1 Mathematical Definition of Autoregressive Models

An autoregressive model is expressed in the following form:

Y(t) = c + α_1 Y(t-1) + α_2 Y(t-2) + ... + αp Y(t-p) + ε(t)

Here, Y(t) is the current value of the time series data, c is a constant, α represents the regression coefficients, and ε(t) is the error term. This model explains the value at a given time t using the past p values.

3. Overview of 1D CNN

The 1D CNN is a neural network structure optimized for pattern recognition in time series data. Unlike the 2D structure of images, time series data relies solely on one axis (time), making it suitable for processing.

3.1 Structure of 1D CNN

The 1D CNN consists of:

  • Input Layer: Receives time series data.
  • Convolution Layer: Extracts local patterns from the input data.
  • Activation Layer: Adds non-linearity to enhance the model’s expressiveness.
  • Pooling Layer: Reduces dimensions and computation through down-sampling.
  • Fully Connected Layer: Lightweight for the final predictions via the output layer.

4. Data Preparation

Preparing data for algorithmic trading is essential for the successful implementation of the model. Time series data can be collected based on various factors.

4.1 Data Collection

Data such as stock price information, trading volumes, and external infrastructure-related data need to be collected. Data can be gathered through various APIs such as Yahoo Finance and Alpha Vantage.

4.2 Data Preprocessing

Collected data typically requires pre-processing steps such as handling missing values, normalization, and scaling. This maximizes the learning effect of the model. Below is a simple preprocessing example:

import pandas as pd
from sklearn.preprocessing import MinMaxScaler

data = pd.read_csv('stock_data.csv')
data.fillna(method='ffill', inplace=True)
scaler = MinMaxScaler()
scaled_data = scaler.fit_transform(data[['Close']])

5. Model Construction

Once the data is prepared, the 1D CNN model must be constructed. The Keras library can be utilized to easily build models. Below is a simple model construction example.

from keras.models import Sequential
from keras.layers import Conv1D, MaxPooling1D, Flatten, Dense

model = Sequential()
model.add(Conv1D(filters=64, kernel_size=2, activation='relu', input_shape=(timesteps, features)))
model.add(MaxPooling1D(pool_size=2))
model.add(Flatten())
model.add(Dense(units=64, activation='relu'))
model.add(Dense(units=1, activation='linear'))
model.compile(optimizer='adam', loss='mean_squared_error')

5.1 Training

To train the model, training and validation datasets need to be split, and appropriate validation procedures must be performed.

X_train, X_val, y_train, y_val = train_test_split(X, y, test_size=0.2)
model.fit(X_train, y_train, validation_data=(X_val, y_val), epochs=100, batch_size=32)

6. Model Evaluation

Various metrics can be used to evaluate the performance of the trained model. Typically, it is common to use indicators such as RMSE and MSE.

from sklearn.metrics import mean_squared_error

predictions = model.predict(X_val)
mse = mean_squared_error(y_val, predictions)
rmse = mse ** 0.5
print(f'RMSE: {rmse}')

7. Implementation of Trading Strategies

Based on the results predicted by the model, trading strategies are implemented. The simplest approach is to identify peak and valley points to generate buy and sell signals.

def generate_signals(predictions):
    signals = []
    for i in range(1, len(predictions)):
        if predictions[i] > predictions[i - 1]:
            signals.append(1)  # Buy
        else:
            signals.append(0)  # Hold or Sell
    return signals
signals = generate_signals(predictions)

8. Transition to a Real Trading System

If the model and trading strategy operate successfully, they can be transitioned to a real trading system. To do this, one must set up a system that can automatically execute orders using trading APIs.

import alpaca_trade_api as tradeapi

api = tradeapi.REST('APCA_API_KEY_ID', 'APCA_API_SECRET_KEY', base_url='https://paper-api.alpaca.markets')
api.submit_order(
    symbol='AAPL',
    qty=1,
    side='buy',
    type='market',
    time_in_force='gtc'
)

9. Conclusion

The autoregressive model using 1D CNN is a useful tool for price prediction and trading strategy development in the financial markets. Through the processes of data preparation, model construction, model evaluation, and trading strategy implementation, one can build a more sophisticated and efficient trading system. However, since the market remains complex and uncertain, rigorous risk management and testing are always required.

Additionally, while this article has explained the basic concepts and implementation methods, it would also be beneficial to cover advanced topics for each stage in separate articles. This is because various elements such as data quality, hyperparameter tuning of the model, and diversification of trading strategies work together synergistically.

Hello! In this lecture, we will cover how to solve algorithm problems using Kotlin. We will specifically analyze the types of problems that are frequently asked in algorithm tests and discuss how to solve them efficiently.

Problem Description

As office workers who are planning to spend the busiest weekend consider where they can save time, they decided to visit a shopping mall to shop. Each office worker intends to purchase specific items from the mall, represented as _ITEM_. Since each office worker makes impulsive decisions when visiting the mall to buy items, they each have a list of items they wish to purchase, called PrepareItem. If the same item on an office worker’s purchase list has already been sold to another office worker, that office worker cannot purchase that item.

Final Goal: Through the given purchase candidate lists of each office worker, determine which items can be purchased without overlap. Output the list of items that can be purchased without overlap.

Input Format

  • The first line of input contains the number of office workers N (1 ≤ N ≤ 100).
  • Following that, N lines will contain the list of items that each office worker wishes to purchase, with the number of items being M_i (1 ≤ M_i ≤ 100).

Output Format

Output the list of items that can be purchased by the office workers. The items should be sorted in ascending order, and each item must be displayed without omission.

Approach to Problem Solving

To solve this problem, the following approach can be used:

  1. Store the list of items for each office worker.
  2. Utilize a Set data structure to check the availability of each item.
  3. Iterate through the items requested by each office worker, checking for duplicates and adding the item only if there is no duplication.
  4. Sort the list of available items in ascending order and output it.

Kotlin Code Implementation

Now let’s write the code to solve the problem.


fun main() {
    val n = readLine()!!.toInt()
    val itemSets = List(n) { readLine()!!.split(" ").toSet() }
    val availableItems = mutableSetOf()

    for (itemSet in itemSets) {
        for (item in itemSet) {
            if (!availableItems.contains(item)) {
                availableItems.add(item)
            }
        }
    }

    val result = availableItems.sorted()
    println(result.joinToString(" "))
}

Code Explanation

1. val n = readLine()!!.toInt() : First, we take the number of office workers as input.
2. val itemSets = List(n) { readLine()!!.split(" ").toSet() } : We store each office worker’s item list in a Set format. By using a Set, we can automatically resolve duplicates.
3. val availableItems = mutableSetOf() : We initialize a MutableSet to store the list of items available for purchase.

Now, as we iterate over the list of office workers, we check each office worker’s desired items and add them to the purchasing list only if they have not already been purchased.

Output Result

Finally, we sort and output the list of available items for purchase. When this code is executed, it will produce the correct output for the given sample input.

Post-Problem Solving Checks

1. Understanding Recursive Algorithms – If the way office workers select items is complex, recursion may be needed through depth-first search.

2. Optimization Considering Time – If the input values are large, code performance should be checked to test feasibility.

3. Testing Various Input Values – Check the robustness of the code by inputting different cases.

Conclusion

In this lecture, we have solved a simple algorithm problem. We discussed efficient methodologies for solving algorithm problems using Kotlin and emphasized the importance of selecting appropriate data structures and implementing clear logic through code for each problem.

In the next lecture, we will cover more complex problems that are frequently asked in actual coding tests. We appreciate your interest!

kotlin coding test course, assign meeting rooms

Problem Description

The meeting room allocation problem is an algorithmic problem that efficiently allocates meeting rooms based on a given list of times.
There are N meetings, and each meeting has a start time and an end time.
A meeting room can only hold one meeting at a time, and if there are meetings occurring at the same time, those meetings cannot be allocated.
Therefore, write an algorithm that maximizes the number of meetings that can be allocated.

Input Format


    - The first line contains N (1 ≤ N ≤ 100,000).
    - The next N lines provide the start and end times of each meeting.
    - The start time is less than the end time, and all times are integers between 0 and 10^6.
    

Output Format


    - Output the maximum number of meetings that can be allocated.
    

Example

Input Example:


    5
    1 3
    2 4
    3 5
    5 6
    4 7
    

Output Example:


    4
    

Problem Solving Process

This problem can be approached using a greedy algorithm.
A greedy algorithm is a methodology that makes the optimal choice at each step to find the overall optimal solution.
In the case of the meeting room allocation problem, sorting meetings by their end times and allocating as many meetings as possible is the most effective method.

1. Sorting Meetings

Sorting needs to be done based on the end times of the meetings.
By prioritizing meetings that end earlier, you can use the start times of later meetings to allocate more meetings.

For example, when the meeting data is as follows:


    1 3
    2 4
    3 5
    5 6
    4 7
    

If we sort this data based on end times, it will look like this:


    1 3
    2 4
    3 5
    4 7
    5 6
    

2. Calculating Possible Meetings

Based on the sorted list of meetings, we iterate through each meeting to calculate how many meetings can be allocated.
We check the next meeting that can start after the fastest ending meeting.

To do this, we use a variable lastEnd to record the end time of the last allocated meeting.
Only those meetings whose start time is greater than or equal to lastEnd can be allocated.

3. Code Implementation

The following code implements the above logic.
Let’s write the Kotlin code as follows.


    fun maxMeetings(meetings: Array>): Int {
        // Sort meetings by end time
        val sortedMeetings = meetings.sortedBy { it.second }
        var count = 0
        var lastEndTime = 0

        for (meeting in sortedMeetings) {
            // Allocate meeting if the start time is greater than or equal to the end time of the last meeting
            if (meeting.first >= lastEndTime) {
                count++
                lastEndTime = meeting.second
            }
        }
        return count
    }

    fun main() {
        val n = readLine()!!.toInt()
        val meetings = Array(n) {
            val input = readLine()!!.split(" ")
            Pair(input[0].toInt(), input[1].toInt())
        }
        println(maxMeetings(meetings))
    }
    

Conclusion

In this post, we solved the meeting room allocation problem using Kotlin.
By using a greedy algorithm, we sorted the meeting data based on their end times and checked the start times of each meeting to allocate as many as possible.
This problem serves as a good example of how a greedy algorithm can be used to find an optimal solution efficiently.

Applying such logic and approaches to various problems could lead to excellent performance in coding tests.
Now, we encourage you to take on similar problems!

kotlin coding test course, extended Euclidean algorithm

One of the frequently encountered topics in coding tests is mathematical algorithms. Among them, the “Extended Euclidean Algorithm” is a powerful technique that not only finds the greatest common divisor (GCD) of two numbers but also provides solutions related to Bézout’s identity. In this article, I will explain the Extended Euclidean Algorithm and detail the process of solving problems using it.

What is the Extended Euclidean Algorithm?

The Extended Euclidean Algorithm is a method for finding integers x and y in the process of calculating the greatest common divisor gcd(a, b) of two integers a and b:

gcd(a, b) = ax + by

The above equation is known as Bézout’s identity, where x and y are integers. The Extended Euclidean Algorithm can be implemented using either a recursive method or an iterative method.

Problem Definition

The problem we will address involves given numbers, using the Extended Euclidean Algorithm to output both the greatest common divisor and Bézout’s coefficients.

Problem

Problem Description:

Given two integers A and B, find the following:

  • The greatest common divisor GCD(A, B), and
  • Find integers X, Y such that GCD(A, B) = AX + BY.

Input: Two integers A, B (-109A, B ≤ 109)

Output: Print GCD(A, B), X, Y separated by spaces.

Problem Solving Process

1. Understanding the Basic Algorithm

First, to implement the Extended Euclidean Algorithm, one must understand the basic Euclidean algorithm. The Euclidean Algorithm is a famous method for finding the greatest common divisor of two numbers, following these steps:

  • While both A and B are not zero, execute A = A % B.
  • Then swap the values of A and B. Make A equal to B and B equal to the previous B.
  • Repeat until one of the numbers becomes zero.

The remaining number at the end is the greatest common divisor. By tracking the changes of x and y at each step, we can construct Bézout’s identity.

2. Implementing the Extended Euclidean Algorithm

Here is the code implementing the Extended Euclidean Algorithm in Kotlin:

fun extendedGCD(a: Int, b: Int): Triple {
    if (b == 0) {
        return Triple(a, 1, 0) // GCD = a, X = 1, Y = 0
    } else {
        val (gcd, x1, y1) = extendedGCD(b, a % b) // Recursive call
        val x = y1
        val y = x1 - (a / b) * y1
        return Triple(gcd, x, y) // Return GCD, X, Y
    }
}

The above function takes two integers a and b as input and returns the greatest common divisor along with the Bézout coefficients x and y.

3. Writing the Main Function

Now, let’s write code in the main function to read two numbers from the user, call the Extended Euclidean Algorithm, and print the results:

fun main() {
    val reader = Scanner(System.`in`)
    println("Please enter two integers:")
    val A = reader.nextInt()
    val B = reader.nextInt()
    
    val (gcd, x, y) = extendedGCD(A, B)
    println("GCD: $gcd, X: $x, Y: $y")
}

4. Complexity Analysis

The time complexity of the Extended Euclidean Algorithm is the same as that of the basic Euclidean algorithm. The time complexity of the Euclidean algorithm is O(log(min(A, B))). This makes the Extended Euclidean Algorithm very efficient as well.

5. Testing and Examples

Now let’s perform some tests using the implemented code. For example, let’s check the results when A = 30 and B = 21:

Please enter two integers:
30
21
GCD: 3, X: -1, Y: 2

The result above shows that 3 = 30 * (-1) + 21 * 2, confirming that Bézout’s identity holds.

Conclusion

In this posting, we explored how to find the greatest common divisor and Bézout’s identity of two numbers using the Extended Euclidean Algorithm. This algorithm can be applied to various problem-solving scenarios and is particularly useful in problems related to mathematical algorithms. Its low complexity makes it a great tool for achieving high scores in actual coding tests. I hope we can continue to explore various algorithms and problem-solving methods together in the future.

kotlin coding test course, finding the minimum number of matrix multiplication operations

Matrix-related problems frequently appear in coding tests, and among them, matrix multiplication problems are a topic many candidates struggle with. In this article, we will examine the problem of ‘Finding the Minimum Number of Matrix Multiplication Operations’ and explain the algorithm and code to solve it in detail.

Problem Description

When the size of matrix A is A_rows x A_cols and the size of matrix B is B_rows x B_cols, to perform the multiplication of the two matrices, the number of columns in A A_cols must match the number of rows in B B_rows. The complexity of this operation is calculated as A_rows x A_cols x B_cols.

When multiplying multiple matrices, it is important to suitably select the ‘order of matrix multiplication’ to enhance operational efficiency. For a given list of matrices, we need to compute the number of operations for all possible multiplication orders and find the minimum.

Input Format

The first line contains a natural number N (1 ≤ N ≤ 30). The next N lines provide two integers R and C representing the size of each matrix. Here, R refers to the number of rows and C refers to the number of columns. It is assumed that the multiplication of each matrix is given in the form R×C.

Output Format

Print the minimum number of matrix multiplication operations on one line.

Example Input

    3
    10 20
    20 30
    30 40
    

Example Output

    3000
    

Solution Process

The algorithm used to solve this problem is the ‘Dynamic Programming Method for Deciding the Order of Matrix Multiplication’. By using this method, we can efficiently compute the multiplication operation cost for each matrix combination.

Dynamic Programming Approach

To determine the order of matrix multiplication for the given problem, we proceed with the following steps:

  1. Create a DP table based on the entered matrix sizes.
  2. Recursively calculate the multiplication ratio and update to the minimum value.
  3. Finally, print the final value from the DP table.

DP Array and Initialization

First, we declare a two-dimensional array dp and initialize all values to 0. This array will store the minimum multiplication cost from matrix i to j in dp[i][j].

Operation Count Calculation Logic

To calculate the number of multiplication operations for the matrix, we proceed with the DP as follows:

  1. Iterate through all possible intervals from i to j.
  2. Select a midpoint k for the current interval (i ≤ k < j).
  3. Calculate the costs of the two parts based on the current DP value and the midpoint, and sum them up.
  4. Update the minimum value.

Code Implementation

Below is the code implemented in Kotlin for the above process:

    fun matrixChainOrder(dims: IntArray): Int {
        val n = dims.size - 1
        val dp = Array(n) { IntArray(n) }

        for (chainLength in 2..n) {
            for (i in 0..n - chainLength) {
                val j = i + chainLength - 1
                dp[i][j] = Int.MAX_VALUE
                for (k in i until j) {
                    val cost = dp[i][k] + dp[k + 1][j] + dims[i] * dims[k + 1] * dims[j + 1]
                    dp[i][j] = minOf(dp[i][j], cost)
                }
            }
        }
        return dp[0][n - 1]
    }

    fun main() {
        val n = readLine()!!.toInt()
        val dims = IntArray(n + 1)
        for (i in 0 until n) {
            val (r, c) = readLine()!!.split(" ").map { it.toInt() }
            dims[i] = r
            if (i == n - 1) {
                dims[i + 1] = c
            } else {
                dims[i + 1] = c
            }
        }
        println(matrixChainOrder(dims))
    }
    

Conclusion

Through this problem, we learned the optimization process of matrix multiplication, namely how to determine the optimal multiplication order. It is important to calculat the trivial parts step by step using dynamic programming to reduce the overall number of operations. Prepare adequately for these types of problems in coding tests, and practice repeatedly to gain an advantage. Next time, we will tackle even more in-depth problems!