public virtual void pointAndParameterFx()
        {
            ImmutableRatesProvider test        = ImmutableRatesProvider.builder(VAL_DATE).fxRateProvider(FX_MATRIX).discountCurve(GBP, DISCOUNT_CURVE_GBP).discountCurve(USD, DISCOUNT_CURVE_USD).build();
            ImmutableRatesProvider test_gbp_up = ImmutableRatesProvider.builder(VAL_DATE).fxRateProvider(FX_MATRIX).discountCurve(GBP, DISCOUNT_CURVE_GBP_UP).discountCurve(USD, DISCOUNT_CURVE_USD).build();
            ImmutableRatesProvider test_gbp_dw = ImmutableRatesProvider.builder(VAL_DATE).fxRateProvider(FX_MATRIX).discountCurve(GBP, DISCOUNT_CURVE_GBP_DOWN).discountCurve(USD, DISCOUNT_CURVE_USD).build();
            ImmutableRatesProvider test_usd_up = ImmutableRatesProvider.builder(VAL_DATE).fxRateProvider(FX_MATRIX).discountCurve(GBP, DISCOUNT_CURVE_GBP).discountCurve(USD, DISCOUNT_CURVE_USD_UP).build();
            ImmutableRatesProvider test_usd_dw = ImmutableRatesProvider.builder(VAL_DATE).fxRateProvider(FX_MATRIX).discountCurve(GBP, DISCOUNT_CURVE_GBP).discountCurve(USD, DISCOUNT_CURVE_USD_DOWN).build();
            LocalDate matuirtyDate             = GBP_USD_WM.calculateMaturityFromFixing(VAL_DATE, REF_DATA);
            double    maturityTime             = DAY_COUNT.relativeYearFraction(VAL_DATE, matuirtyDate);
            // GBP based
            FxIndexObservation      obs = FxIndexObservation.of(GBP_USD_WM, VAL_DATE, REF_DATA);
            PointSensitivityBuilder sensiBuildCmpGBP = test.fxIndexRates(GBP_USD_WM).ratePointSensitivity(obs, GBP);
            FxIndexSensitivity      sensiBuildExpGBP = FxIndexSensitivity.of(obs, GBP, USD, 1.0);

            assertTrue(sensiBuildCmpGBP.Equals(sensiBuildExpGBP));
            double sense_gbp1 = 0.5 * (test_gbp_up.fxIndexRates(GBP_USD_WM).rate(obs, GBP) - test_gbp_dw.fxIndexRates(GBP_USD_WM).rate(obs, GBP)) / EPS_FD * (-maturityTime * GBP_DSC);
            double sense_usd1 = 0.5 * (test_usd_up.fxIndexRates(GBP_USD_WM).rate(obs, GBP) - test_usd_dw.fxIndexRates(GBP_USD_WM).rate(obs, GBP)) / EPS_FD * (-maturityTime * USD_DSC);
            PointSensitivityBuilder sensiBuildDecGBP = ZeroRateSensitivity.of(GBP, maturityTime, USD, sense_gbp1);

            sensiBuildDecGBP = sensiBuildDecGBP.combinedWith(ZeroRateSensitivity.of(USD, maturityTime, USD, sense_usd1));
            CurrencyParameterSensitivities paramSensiCmpGBP = test.parameterSensitivity(sensiBuildCmpGBP.build().normalized());
            CurrencyParameterSensitivities paramSensiExpGBP = test.parameterSensitivity(sensiBuildDecGBP.build().normalized());

            assertTrue(paramSensiCmpGBP.equalWithTolerance(paramSensiExpGBP, EPS_FD));
            // USD based
            PointSensitivityBuilder sensiBuildCmpUSD = test.fxIndexRates(GBP_USD_WM).ratePointSensitivity(obs, USD);
            FxIndexSensitivity      sensiBuildExpUSD = FxIndexSensitivity.of(obs, USD, GBP, 1.0);

            assertTrue(sensiBuildCmpUSD.Equals(sensiBuildExpUSD));
            double sense_gbp2 = 0.5 * (test_gbp_up.fxIndexRates(GBP_USD_WM).rate(obs, USD) - test_gbp_dw.fxIndexRates(GBP_USD_WM).rate(obs, USD)) / EPS_FD * (-maturityTime * GBP_DSC);
            double sense_usd2 = 0.5 * (test_usd_up.fxIndexRates(GBP_USD_WM).rate(obs, USD) - test_usd_dw.fxIndexRates(GBP_USD_WM).rate(obs, USD)) / EPS_FD * (-maturityTime * USD_DSC);
            PointSensitivityBuilder sensiBuildDecUSD = ZeroRateSensitivity.of(GBP, maturityTime, GBP, sense_gbp2);

            sensiBuildDecUSD = sensiBuildDecUSD.combinedWith(ZeroRateSensitivity.of(USD, maturityTime, GBP, sense_usd2));
            CurrencyParameterSensitivities paramSensiCmpUSD = test.parameterSensitivity(sensiBuildCmpUSD.build().normalized());
            CurrencyParameterSensitivities paramSensiExpUSD = test.parameterSensitivity(sensiBuildDecUSD.build().normalized());

            assertTrue(paramSensiCmpUSD.equalWithTolerance(paramSensiExpUSD, EPS_FD));
        }