equals( sh ) {

		for ( let i = 0; i < 9; i ++ ) {

			if ( ! this.coefficients[ i ].equals( sh.coefficients[ i ] ) ) {

				return false;

			}

		}

		return true;

	}
Returns `true` if this spherical harmonics is equal with the given one.

@param {SphericalHarmonics3} sh - The spherical harmonics to test for equality.
@return {boolean} Whether this spherical harmonics is equal with the given one.