import Vector 	from "./Vector.js"

function random() {
	let seed = 12345; // fixed seed

	return function() {
		seed = ( seed * 16807 ) % 2147483647;
		return ( seed - 1 ) / 2147483646;
	};
}

const randomFix = random();

export default class Matrix {
	constructor( rows, cols, fillValue = 0 ) {
		this.rows = rows;
		this.cols = cols;
		this.data = new Array( rows );
		for ( let i = 0 ; i < rows ; i++ ) {
			this.data[ i ] = new Array( cols );
			for ( let j = 0 ; j < cols ; j++ ) {
				this.data[ i ][ j ] = fillValue;
			}
		}
	}

	static random( rows, cols, scale = 0.1 ) {
		const mat = new Matrix( rows, cols );
		for ( let i = 0 ; i < rows ; i++ ) {
			for ( let j = 0 ; j < cols ; j++ ) {
				mat.data[ i ][ j ] = ( randomFix() - 0.5 ) * scale;
			}
		}
		return mat;
	}

	static matVecMul( mat, vec ) {
		const result = new Vector( mat.rows );
		for ( let i = 0 ; i < mat.rows ; i++ ) {
			let sum = 0;
			for ( let j = 0 ; j < mat.cols ; j++ ) {
				sum += mat.data[ i ][ j ] * vec.data[ j ];
			}
			result.data[ i ] = sum;
		}
		return result;
	}
}