add some calculation multi feature process data

Author: FarrelAD

src/cli/multi-feature.js

@@ -1,25 +1,137 @@
-import { confirm } from '@inquirer/prompts'
+import process from 'process'
+import chalk from 'chalk'
+import inquirer from 'inquirer'
+import { input, confirm } from '@inquirer/prompts'
 
 
+
+// Simplify std out from `console.log` into `print`
 const print = console.log;
 
 
-export default async function multiFeatureProcess() {
-    print('Multi feature process')
 
-    if (await confirm({ message: 'Show visualization?'})) {
-        visualization()
+/**
+ * Process linear regression with multi feature
+ * 
+ * Formula
+ * y = a + bx
+ * 
+ * @param {Array} data - the raw data
+ */
+export default async function multiFeatureProcess(data) {
+    print('=====================================================\n')
+    print(chalk.blue('MULTI FEATURE PROCESS\n'))
+
+    const answers = await inquirer.prompt([
+        {
+            type: 'checkbox',
+            name: 'features',
+            message: 'Choose independent variable',
+            choices: Object.keys(data[0])
+        },
+        {
+            type: 'list',
+            name: 'label',
+            message: 'Choose dependent variable',
+            choices: Object.keys(data[0])
+        }
+    ])
+
+
+    for (const feature of answers.features) {
+        if (feature == answers.label) {
+            print(chalk.redBright('\n[!]  Feature and label can not be same'))
+            
+            if (await confirm({ message: 'Back?'})) return;
+        }
     }
-}
 
 
+    // const numberPattern = /^[+-]?\d+(\.\d+)?$/
+    // for (const item of data) {
+    //     if (!numberPattern.test(item[answers.features]) || !numberPattern.test(item[answers.label])) {
+    //         print(chalk.redBright('\n[!]  Some data is not a number! Unable to process further!'))
+    //         await confirm({ message: 'Continue?'})
+    //         return;
+    //     }
+    // }
+
+
+    /**
+     * Calculate the value a and b to get equation y = a + bx
+    */
+    const sumY = data.reduce((sum, val) => sum + parseInt(val[answers.label]), 0)
+
+    const sumXi = []
+    const sumXiSquared = []
+    const sumXiYi = [] // ? how ?
+    
+    for (let i = 0; i < answers.features.length; i++) {
+        sumXi.push(data.reduce((sum, val) => sum + parseInt(val[answers.features[i]]), 0))
+        sumXiSquared.push(data.reduce((sum, val) => sum + parseInt(val[answers.features[i]]) ** 2, 0))
+    }
+
+    const sumAllXi = sumXi.reduce((sum, val) => sum * val)
+    const sumAllXiSquared = sumXiSquared.reduce((sum, val) => sum * val)
+
+    const slopes = []
+    for (let i = 0; i < answers.features.length; i++) {
+        slopes.push(
+            ((data.length * sumXiYi) - (sumAllXi * sumY)) /
+            ((data.length * sumAllXiSquared) - (sumAllXi ** 2))
+        )
+    }
+
+    let sumSlopeiXi = 0
+    for (let i = 0; i < slopes.length; i++) {
+        sumSlopeiXi += slopes[i] * (sumXi[i] / data.length)
+    }
+
 
-function visualization() {
-    print('\n-----------------------------------------------------\n')
-    print('Visualization here!')
-    print('Graph, chart, or whatever...')
+    /**
+     * INSPECTION!
+     */
+    print('sumY: ', sumY)
+    print('sumXi: ', sumXi)
+    print('slopes: ', slopes)
+    print('sumXiSquare: ', sumXiSquared)
+    print('sumAllXiSquared: ', sumAllXiSquared)
+    print('sumXiYi: ', sumXiYi)
+
+    const a = (sumY / data.length) - sumSlopeiXi
+
+    // Equation result
+    const y = (...x) => a + slopes.reduce((sum, val, index) => sum + (val * x[index]))
+
+
+    // Print the equation
+    process.stdout.write(chalk.blueBright(`\nEquation result: ${a} + `))
+
+    slopes.forEach((val, index) => {
+        process.stdout.write(chalk.blueBright(`${val}x\u1d62`))
+        if (index != slopes.length - 1) process.stdout.write(chalk.blueBright(' + '))
+    })
+
+
+
+    if (await confirm({ message: 'Do you want to test?'})) {
+        do {
+            await testing(y, answers.feature, answers.label)
+        } while (await confirm({ message: 'Do you want to test again?'}));
+    }
+    
+
+    evaluation()
+}
+
+
+async function testing(y, feature, label) {
+    const inputFeature = await input({message: `Input ${feature}`})
+    print(`Prediction ${label}: ${y(inputFeature)}`)
+}
 
 
-    // 7
-    print('Show the prove of linear equation is actually match with user data')
+function evaluation() {
+    print('Evaluation!')
+    print('MSE, MAE, RMSE')
 }