diff --git a/src/hydro/Gadget2/hydro.h b/src/hydro/Gadget2/hydro.h
index 09a8f50d5b2e9abd43c3b9bd43a12fad8a347258..2b17505c36f345779b269c90758931a13f9b4e0d 100644
--- a/src/hydro/Gadget2/hydro.h
+++ b/src/hydro/Gadget2/hydro.h
@@ -19,6 +19,18 @@
 #ifndef SWIFT_GADGET2_HYDRO_H
 #define SWIFT_GADGET2_HYDRO_H
 
+/**
+ * @file Gadget2/hydro.h
+ * @brief SPH interaction functions following the Gadget-2 version of SPH.
+ *
+ * The interactions computed here are the ones presented in the Gadget-2 paper
+ * Springel, V., MNRAS, Volume 364, Issue 4, pp. 1105-1134.
+ * We use the same numerical coefficients as the Gadget-2 code. When used with
+ * the Spline-3 kernel, the results should be equivalent to the ones obtained
+ * with Gadget-2 up to the rounding errors and interactions missed by the
+ * Gadget-2 tree-code neighbours search.
+ */
+
 #include "adiabatic_index.h"
 #include "approx_math.h"
 #include "dimension.h"
diff --git a/src/hydro/Gadget2/hydro_iact.h b/src/hydro/Gadget2/hydro_iact.h
index 82e98e87d0a50ee4346d272c7fbd1ba3f4316fc7..5ee8cd0370a970aa83cef3d1c8909d923c12ba24 100644
--- a/src/hydro/Gadget2/hydro_iact.h
+++ b/src/hydro/Gadget2/hydro_iact.h
@@ -20,18 +20,20 @@
 #ifndef SWIFT_GADGET2_HYDRO_IACT_H
 #define SWIFT_GADGET2_HYDRO_IACT_H
 
-#include "minmax.h"
-
 /**
+ * @file Gadget2/hydro_iact.h
  * @brief SPH interaction functions following the Gadget-2 version of SPH.
  *
  * The interactions computed here are the ones presented in the Gadget-2 paper
- * and use the same numerical coefficients as the Gadget-2 code. When used with
+ * Springel, V., MNRAS, Volume 364, Issue 4, pp. 1105-1134.
+ * We use the same numerical coefficients as the Gadget-2 code. When used with
  * the Spline-3 kernel, the results should be equivalent to the ones obtained
  * with Gadget-2 up to the rounding errors and interactions missed by the
  * Gadget-2 tree-code neighbours search.
  */
 
+#include "minmax.h"
+
 /**
  * @brief Density loop
  */
diff --git a/src/hydro/Gadget2/hydro_part.h b/src/hydro/Gadget2/hydro_part.h
index eac324c90c30aff6a54c7f961fe40b0ddf811c14..2c12a71ad6256d7372256b6e590790ee0ff4e22e 100644
--- a/src/hydro/Gadget2/hydro_part.h
+++ b/src/hydro/Gadget2/hydro_part.h
@@ -19,6 +19,18 @@
 #ifndef SWIFT_GADGET2_HYDRO_PART_H
 #define SWIFT_GADGET2_HYDRO_PART_H
 
+/**
+ * @file Gadget2/hydro_part.h
+ * @brief SPH interaction functions following the Gadget-2 version of SPH.
+ *
+ * The interactions computed here are the ones presented in the Gadget-2 paper
+ * Springel, V., MNRAS, Volume 364, Issue 4, pp. 1105-1134.
+ * We use the same numerical coefficients as the Gadget-2 code. When used with
+ * the Spline-3 kernel, the results should be equivalent to the ones obtained
+ * with Gadget-2 up to the rounding errors and interactions missed by the
+ * Gadget-2 tree-code neighbours search.
+ */
+
 #include "cooling_struct.h"
 
 /* Extra particle data not needed during the SPH loops over neighbours. */
diff --git a/src/hydro/Minimal/hydro.h b/src/hydro/Minimal/hydro.h
index 0bbc77f4a2384c79f7d3329c20b92990598d5c63..eeb389537c56876126c60b2d29a728029c72844b 100644
--- a/src/hydro/Minimal/hydro.h
+++ b/src/hydro/Minimal/hydro.h
@@ -29,9 +29,8 @@
  * term is implemented.
  *
  * This corresponds to equations (43), (44), (45), (101), (103)  and (104) with
- * \f$\beta=3\f$ and \f$\alpha_u=0\f$ of
- * Price, D., Journal of Computational Physics, 2012, Volume 231, Issue 3,
- * pp. 759-794.
+ * \f$\beta=3\f$ and \f$\alpha_u=0\f$ of Price, D., Journal of Computational
+ * Physics, 2012, Volume 231, Issue 3, pp. 759-794.
  */
 
 #include "adiabatic_index.h"
diff --git a/src/hydro/Minimal/hydro_iact.h b/src/hydro/Minimal/hydro_iact.h
index 9e2028c978dc7cad03cfba17931f645bbfbfe1a0..edb060e4fd71fcc136e1bedf6e8a752d1d50d54f 100644
--- a/src/hydro/Minimal/hydro_iact.h
+++ b/src/hydro/Minimal/hydro_iact.h
@@ -28,9 +28,8 @@
  * term is implemented.
  *
  * This corresponds to equations (43), (44), (45), (101), (103)  and (104) with
- * \f$\beta=3\f$ and \f$\alpha_u=0\f$ of
- * Price, D., Journal of Computational Physics, 2012, Volume 231, Issue 3,
- * pp. 759-794.
+ * \f$\beta=3\f$ and \f$\alpha_u=0\f$ of Price, D., Journal of Computational
+ * Physics, 2012, Volume 231, Issue 3, pp. 759-794.
  */
 
 #include "adiabatic_index.h"
diff --git a/src/hydro/Minimal/hydro_part.h b/src/hydro/Minimal/hydro_part.h
index c83797b42b73f8cd8dd5bc993053769ba0cd354e..8e23bddf5153043421319810683266b27d297f93 100644
--- a/src/hydro/Minimal/hydro_part.h
+++ b/src/hydro/Minimal/hydro_part.h
@@ -28,9 +28,8 @@
  * term is implemented.
  *
  * This corresponds to equations (43), (44), (45), (101), (103)  and (104) with
- * \f$\beta=3\f$ and \f$\alpha_u=0\f$ of
- * Price, D., Journal of Computational Physics, 2012, Volume 231, Issue 3,
- * pp. 759-794.
+ * \f$\beta=3\f$ and \f$\alpha_u=0\f$ of Price, D., Journal of Computational
+ * Physics, 2012, Volume 231, Issue 3, pp. 759-794.
  */
 
 #include "cooling_struct.h"
@@ -44,13 +43,14 @@
  */
 struct xpart {
 
-  float x_diff[3]; /*!< Offset between current position and position at last
-                      tree rebuild. */
+  /*! Offset between current position and position at last tree rebuild. */
+  float x_diff[3];
 
-  float v_full[3]; /*!< Velocity at the last full step. */
+  /*! Velocity at the last full step. */
+  float v_full[3];
 
-  struct cooling_xpart_data
-      cooling_data; /*!< Additional data used to record cooling information */
+  /*! Additional data used to record cooling information */
+  struct cooling_xpart_data cooling_data;
 
 } SWIFT_STRUCT_ALIGN;
 
@@ -63,27 +63,38 @@ struct xpart {
  */
 struct part {
 
-  double x[3]; /*!< Particle position. */
+  /*! Particle position. */
+  double x[3];
 
-  float v[3]; /*!< Particle predicted velocity. */
+  /*! Particle predicted velocity. */
+  float v[3];
 
-  float a_hydro[3]; /*!< Particle acceleration. */
+  /*! Particle acceleration. */
+  float a_hydro[3];
 
-  float mass; /*!< Particle mass. */
+  /*! Particle mass. */
+  float mass;
 
-  float h; /*!< Particle smoothing length. */
+  /*! Particle smoothing length. */
+  float h;
 
-  int ti_begin; /*!< Time at the beginning of time-step. */
+  /*! Time at the beginning of time-step. */
+  int ti_begin;
 
-  int ti_end; /*!< Time at the end of time-step. */
+  /*! Time at the end of time-step. */
+  int ti_end;
 
-  float u; /*!< Particle internal energy. */
+  /*! Particle internal energy. */
+  float u;
 
-  float u_dt; /*!< Time derivative of the internal energy. */
+  /*! Time derivative of the internal energy. */
+  float u_dt;
 
-  float rho; /*!< Particle density. */
+  /*! Particle density. */
+  float rho;
 
-  float rho_dh; /*!< Derivative of density with respect to h */
+  /*! Derivative of density with respect to h */
+  float rho_dh;
 
   /* Store density/force specific stuff. */
   union {
@@ -97,10 +108,12 @@ struct part {
      */
     struct {
 
-      float wcount; /*!< Neighbour number count. */
+      /*! Neighbour number count. */
+      float wcount;
+
+      /*! Derivative of the neighbour number with respect to h. */
+      float wcount_dh;
 
-      float wcount_dh; /*!< Derivative of the neighbour number with respect to
-                          h. */
     } density;
 
     /**
@@ -112,19 +125,24 @@ struct part {
      */
     struct {
 
-      float pressure; /*!< Particle pressure. */
+      /*! Particle pressure. */
+      float pressure;
 
-      float v_sig; /*!< Particle signal velocity */
+      /*! Particle signal velocity */
+      float v_sig;
 
-      float h_dt; /*!< Time derivative of smoothing length  */
+      /*! Time derivative of smoothing length  */
+      float h_dt;
 
     } force;
   };
 
-  long long id; /*!< Particle unique ID. */
+  /*! Particle unique ID. */
+  long long id;
 
-  struct gpart* gpart; /*!< Pointer to corresponding gravity part. */
+  /*! Pointer to corresponding gravity part. */
+  struct gpart* gpart;
 
-} __attribute__((aligned(part_align)));
+} SWIFT_STRUCT_ALIGN;
 
 #endif /* SWIFT_MINIMAL_HYDRO_PART_H */