diff --git a/algo/ca/core/data/CaMeasurementXy.h b/algo/ca/core/data/CaMeasurementXy.h
index 426f6b6b9526508f80214c7759799bd437a9d7f2..a705fb05edd6d0b1d076985026573aa258cd1956 100644
--- a/algo/ca/core/data/CaMeasurementXy.h
+++ b/algo/ca/core/data/CaMeasurementXy.h
@@ -175,18 +175,23 @@ namespace cbm::algo::ca
///------------------------------
/// Data members
- DataT fX {constants::Undef<DataT>}; ///< x coordinate of the measurement
- DataT fY {constants::Undef<DataT>}; ///< y coordinate of the measurement
- DataT fDx2 {constants::Undef<DataT>}; ///< rms^2 of the x coordinate measurement
- DataT fDy2 {constants::Undef<DataT>}; ///< rms^2 of the y coordinate measurement
- DataT fDxy {constants::Undef<DataT>}; ///< covariance of the x and y coordinate measurements
+ // Initializing parameters with NANs spoils the track fit where
+ // the masked-out SIMD entries are suppressed by a multication by 0.
+ // Therefore, we initialize the data members here with finite numbers.
+ // For the numerical safety, with some reasonable numbers.
+
+ DataT fX {0.}; ///< x coordinate of the measurement
+ DataT fY {0.}; ///< y coordinate of the measurement
+ DataT fDx2 {1.}; ///< rms^2 of the x coordinate measurement
+ DataT fDy2 {1.}; ///< rms^2 of the y coordinate measurement
+ DataT fDxy {0.}; ///< covariance of the x and y coordinate measurements
/// number of degrees of freedom (used for chi2 calculation)
/// if ndf == 1, the measurement is used in the chi2 calculation
/// if ndf == 0, the measurement is not used in the chi2 calculation
- DataT fNdfX = constants::Undef<DataT>; ///< ndf for the x coordinate measurement
- DataT fNdfY = constants::Undef<DataT>; ///< ndf for the y coordinate measurement
+ DataT fNdfX = 0.; ///< ndf for the x coordinate measurement
+ DataT fNdfY = 0.; ///< ndf for the y coordinate measurement
} _fvecalignment;
diff --git a/algo/ca/core/data/CaTrackParam.h b/algo/ca/core/data/CaTrackParam.h
index 8f1cf3a425f7d68a5939ccb4a472327121db94d2..b09731e47e4f36f94fc94110df5f01ba7da13089 100644
--- a/algo/ca/core/data/CaTrackParam.h
+++ b/algo/ca/core/data/CaTrackParam.h
@@ -537,26 +537,34 @@ namespace cbm::algo::ca
/// ---------------------------------------------------------------------------------------------------------------------
/// Class members
- // ! CI tests are failing by timeout when using undef values
- // TODO: fix it and uncomment the line below
- //static constexpr auto kUndef = cbm::algo::ca::constants::Undef<DataT>;
- static constexpr auto kUndef = 0.;
-
- CovMatrix_t fCovMatrix {kUndef}; ///< covariance matrix
-
- DataT fX {kUndef}; ///< x-position [cm]
- DataT fY {kUndef}; ///< y-position [cm]
- DataT fZ {kUndef}; ///< z-position [cm]
- DataT fTx {kUndef}; ///< slope along x-axis
- DataT fTy {kUndef}; ///< slope along y-axis
- DataT fQp {kUndef}; ///< charge over momentum [ec/GeV]
- DataT fT {kUndef}; ///< time [ns]
- DataT fVi {kUndef}; ///< inverse velocity in downstream direction [ns/cm]
-
- DataT fChiSq {kUndef}; ///< chi^2 of track fit, spatial measurements
- DataT fNdf {kUndef}; ///< NDF of track fit, spatial measurements
- DataT fChiSqTime {kUndef}; ///< chi^2 of track fit, time measurements
- DataT fNdfTime {kUndef}; ///< NDF of track fit, time measurements
+ // Initializing parameters with NANs spoils the track fit where
+ // the masked-out SIMD entries are suppressed by a multication by 0.
+ // Therefore, we initialize the data members here with finite numbers.
+ // For the numerical safety, with some reasonable numbers.
+
+ // clang-format off
+ CovMatrix_t fCovMatrix {1.,
+ 0., 1.,
+ 0., 0., 1.,
+ 0., 0., 0., 1.,
+ 0., 0., 0., 0., 1.,
+ 0., 0., 0., 0., 0., 1.,
+ 0., 0., 0., 0., 0., 0., 1.}; ///< covariance matrix
+ // clang-format on
+
+ DataT fX {0.}; ///< x-position [cm]
+ DataT fY {0.}; ///< y-position [cm]
+ DataT fZ {0.}; ///< z-position [cm]
+ DataT fTx {0.}; ///< slope along x-axis
+ DataT fTy {0.}; ///< slope along y-axis
+ DataT fQp {0.}; ///< charge over momentum [ec/GeV]
+ DataT fT {0.}; ///< time [ns]
+ DataT fVi {0.}; ///< inverse velocity in downstream direction [ns/cm]
+
+ DataT fChiSq {0.}; ///< chi^2 of track fit, spatial measurements
+ DataT fNdf {0.}; ///< NDF of track fit, spatial measurements
+ DataT fChiSqTime {0.}; ///< chi^2 of track fit, time measurements
+ DataT fNdfTime {0.}; ///< NDF of track fit, time measurements
} _fvecalignment; // class TrackParamBase