Added invertible matrix method

matrix.ts

@@ -80,8 +80,9 @@ export class Matrix {
 	}
 
 	pow(power: number) {
-		for(let i=0; i<(power-1); i++)
-			this.set(...this.mul(this).matrix);
+		if(power > 0)
+			for(let i=0; i<(power-1); i++)
+				this.set(...this.mul(this).matrix);
 		return this;
 	}
 
@@ -159,6 +160,22 @@ export class Matrix {
 		m.splice(row, 1); this.set(...m);
 	}
 
+	invertible() {
+		let matrix = Matrix.zero(this.rows, this.cols*2);
+		this.matrix.forEach((row, i) => {
+			matrix.matrix[i][this.cols+i] = 1;
+			row.forEach((col, j) => {
+				matrix.matrix[i][j] = col;
+			});
+		});
+		let gje = GaussianElimination.gje(matrix).matrix.map(GaussianElimination.make_pivot_1);
+		let result = Matrix.zero(this.rows, this.cols);
+		result.set(...result.matrix.map((row, i) => {
+			return row.map((col, j) => gje[i][this.cols+j]);
+		}));
+		return result;
+	}
+
 }