isUnitary(epsilon) {
        let n = this.width();
        if (this.height() !== n) {
            return false;
        }
        return this.times(this.adjoint()).isApproximatelyEqualTo(Matrix.identity(n), epsilon);
    }
Determines if the matrix is approximately unitary or not.
@param {!number} epsilon Distance away from unitary the matrix is allowed to be. Defaults to 0.
@returns {!boolean}