vendor: Update vendored sources to igraph/igraph@27624a9 (#1672)

Co-authored-by: krlmlr <[email protected]>

src/vendor/cigraph/src/layout/fruchterman_reingold.c

@@ -332,10 +332,11 @@ static igraph_error_t igraph_layout_i_grid_fr(
  *        IGRAPH_LAYOUT_AUTOGRID. The last one uses the grid based
  *        version only for large graphs, currently the ones with
  *        more than 1000 vertices.
- * \param weights Pointer to a vector containing edge weights,
- *        the attraction along the edges will be multiplied by these.
- *        Weights must be positive.
- *        It will be ignored if it is a null-pointer.
+ * \param weights Pointer to a vector containing edge weights. Weights must
+ *        be positive. If \c NULL, all edges are assumed to have weight 1.
+ *        The attraction along the edges will be multiplied by the weights,
+ *        resulting in vertices connected by a high-weight edge being placed
+ *        closer together.
  * \param minx Pointer to a vector, or a \c NULL pointer. If not a
  *        \c NULL pointer then the vector gives the minimum
  *        \quote x \endquote coordinate for every vertex.
@@ -441,10 +442,11 @@ igraph_error_t igraph_layout_fruchterman_reingold(const igraph_t *graph,
  *        of movement alloved along one axis, within one step, for a
  *        vertex. Currently it is decreased linearly to zero during
  *        the iteration.
- * \param weights Pointer to a vector containing edge weights,
- *        the attraction along the edges will be multiplied by these.
- *        Weights must be positive.
- *        It will be ignored if it is a null-pointer.
+ * \param weights Pointer to a vector containing edge weights. Weights must
+ *        be positive. If \c NULL, all edges are assumed to have weight 1.
+ *        The attraction along the edges will be multiplied by the weights,
+ *        resulting in vertices connected by a high-weight edge being placed
+ *        closer together.
  * \param minx Pointer to a vector, or a \c NULL pointer. If not a
  *        \c NULL pointer then the vector gives the minimum
  *        \quote x \endquote coordinate for every vertex.

src/vendor/cigraph/src/layout/kamada_kawai.c

@@ -78,8 +78,10 @@
  *        and then \p maxiter iterations are performed.
  * \param kkconst The Kamada-Kawai vertex attraction constant.
  *        Typical value: number of vertices.
- * \param weights Edge weights, larger values will result longer edges.
- *        Weights must be positive. Pass \c NULL to assume unit weights
+ * \param weights A vector of edge weights. Weights are interpreted as edge
+ *        \em lengths in the shortest path calculation used by the
+ *        Kamada-Kawai algorithm. Therefore, vertices connected by high-weight
+ *        edges will be placed further apart. Pass \c NULL to assume unit weights
  *        for all edges.
  * \param minx Pointer to a vector, or a \c NULL pointer. If not a
  *        \c NULL pointer then the vector gives the minimum
@@ -383,8 +385,10 @@ igraph_error_t igraph_layout_kamada_kawai(const igraph_t *graph, igraph_matrix_t
  *        and then \p maxiter iterations are performed.
  * \param kkconst The Kamada-Kawai vertex attraction constant.
  *        Typical value: number of vertices.
- * \param weights Edge weights, larger values will result longer edges.
- *        Weights must be positive. Pass \c NULL to assume unit weights
+ * \param weights A vector of edge weights. Weights are interpreted as edge
+ *        \em lengths in the shortest path calculation used by the
+ *        Kamada-Kawai algorithm. Therefore, vertices connected by high-weight
+ *        edges will be placed further apart. Pass \c NULL to assume unit weights
  *        for all edges.
  * \param minx Pointer to a vector, or a \c NULL pointer. If not a
  *        \c NULL pointer then the vector gives the minimum

src/vendor/igraph_version.h

@@ -28,11 +28,11 @@
 
 __BEGIN_DECLS
 
-#define IGRAPH_VERSION "0.10.15-48-g2ab6b8794"
+#define IGRAPH_VERSION "0.10.15-50-g27624a9b6"
 #define IGRAPH_VERSION_MAJOR 0
 #define IGRAPH_VERSION_MINOR 10
 #define IGRAPH_VERSION_PATCH 15
-#define IGRAPH_VERSION_PRERELEASE "48-g2ab6b8794"
+#define IGRAPH_VERSION_PRERELEASE "50-g27624a9b6"
 
 IGRAPH_EXPORT void igraph_version(const char **version_string,
                                   int *major,