isCommutative(df, reverse = false) {
        if (!(df instanceof DataFrame))
            throw new ArgumentTypeError(df, "DataFrame");
        return arrayEqual(
            this.df.dim(),
            reverse ? df.dim().reverse() : df.dim(),
            true
        );
    }
Check if two DataFrames are commutative, if both have the same dimensions.
@param {DataFrame} df The second DataFrame to check.
@param {Boolean} [reverse = false] Revert the second DataFrame before the comparison.
@returns {Boolean} True if they are commutative, else false.
@example
df.matrix.isCommutative(df2)