lib/utils/1D/evalError/evalError.js

import { evalGuess } from '../evalGuess/evalGuess';


/** 
Returns an error value from inputs and weights
@param {array[numbers]} inputArr - An array representing the values to be evaluated, with the y value in the [0] position
@param {array[numbers]} weightArr - An array representing the weights to be used with the values, with b0 in the [0] position
@return {number} Sum of errors using the weightArr
*/
export function evalError(inputArr, weightArr) {

	if(!Array.isArray(inputArr)) {
		throw new Error('evalError: InputArr is not an array');
	}

	if(!Array.isArray(inputArr[0])) {
		return inputArr[0] - evalGuess(inputArr, weightArr);

	} else {
		return inputArr.reduce((prev, curr, i) => {
			if(!Array.isArray(curr) || typeof curr[0] != 'number') {
				throw new Error('evalError: A value in inputArr is not an array of numbers');
			}

			if(Array.isArray(prev)) {
				prev = prev[0] - evalGuess(prev, weightArr);
			}

			curr = curr[0] - evalGuess(curr, weightArr);

			return prev + curr;
		})
	}
}