Update interconnectivity.rst (#2353)

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---------

Co-authored-by: Thorsten Hater <[email protected]>

doc/cpp/interconnectivity.rst

@@ -12,7 +12,7 @@ Interconnectivity
  a cell or a spike source. The target is a synapse on the post-synaptic cell.
 
  The :cpp:member:`target` does not include the gid of a cell, this is because a
- :cpp:class:`cell_connection` is bound to the target cell which means that the gid
+ :cpp:class:`cell_connection` is bound to the target cell, which means that the gid
  is implicitly known.
 
  .. cpp:member:: cell_global_label_type source
@@ -45,13 +45,22 @@ Interconnectivity
  a cell or a spike source. The target is a synapse on the post-synaptic cell.
 
  The :cpp:member:`target` does not include the gid of a cell, this is because a
- :cpp:class:`ext_cell_connection` is bound to the target cell which means that the gid
+ :cpp:class:`ext_cell_connection` is bound to the target cell, which means that the ``gid``
  is implicitly known.
 
  .. cpp:member:: cell_remote_label_type source
 
- Source end point, represented by a :cpp:type:`cell_remote_label_type` which packages
- a cell gid, integral tag of a group of sources on the cell, and source selection policy.
+ Source end point, comprising
+
+ - global id, uniquely identifying the source object inside the remote simulation,
+ - local id, uniquely identifying the location of the source on the source object,
+ - selection policy, how to map sources `(gid, lid)` to the targets in Arbor.
+
+ .. Note::
+ The tuple ``(gid, lid)`` must be unique for each source. This addressing scheme follows Arbor's model of multiple
+ sources (threshold detectors) per cell. If the remote simulation does not provide multiple items per
+ source object, ``lid`` can be ignored and set to zero.
+
 
  .. cpp:member:: cell_local_label_type target
 
@@ -76,7 +85,7 @@ Interconnectivity
 
  Describes a gap junction connection between two gap junction sites. The :cpp:member:`local` site does
  not include the gid of a cell, this is because a :cpp:class:`gap_junction_connection` is bound to the local
- cell which means that the gid is implicitly known.
+ cell, which means that the gid is implicitly known.
 
  .. note::
 
@@ -140,11 +149,11 @@ Interconnectivity
 
 .. cpp:class:: network_value
 
- A network value, describing the its calculation for each connection.
+ A network value, describing the calculation for each connection.
 
  .. cpp:function:: network_value scalar(double value)
 
- A fixed scalar valaue.
+ A fixed scalar value.
 
  .. cpp:function:: network_value named(std::string name)
 
@@ -160,11 +169,11 @@ Interconnectivity
 
  .. cpp:function:: network_value normal_distribution(unsigned seed, double mean, double std_deviation)
 
- A normal random distribution with given mean and standard deviation.
+ A normal random distribution with a given mean and standard deviation.
 
  .. cpp:function:: network_value truncated_normal_distribution(unsigned seed, double mean, double std_deviation, const std::array<double, 2>& range)
 
- A truncated normal random distribution with given mean and standard deviation. Sampled through accept-reject method to only returns values in [range_0, range_1)
+ A truncated normal random distribution with a given mean and standard deviation. Sampled through an accept-reject method to only return values in [range_0, range_1)
 
  .. cpp:function:: network_value custom(custom_func_type func)
 
@@ -196,11 +205,11 @@ Interconnectivity
 
  .. cpp:function:: network_value exp(network_value v)
 
- Exponential of given value.
+ Exponential of a given value.
 
  .. cpp:function:: network_value log(network_value v)
 
- Logarithm of given value.
+ Logarithm of a given value.
 
  .. cpp:function:: if_else(network_selection cond, network_value true_value, network_value false_value)
 
@@ -293,7 +302,7 @@ Interconnectivity
 
  .. cpp:function:: network_selection random(unsigned seed, network_value p);
 
- Random selection using the bernoulli random distribution with probability "p" between 0.0 and 1.0
+ Random selection using the Bernoulli random distribution with probability "p" between 0.0 and 1.0
 
  .. cpp:function:: network_selection custom(custom_func_type func);
 
@@ -303,12 +312,12 @@ Interconnectivity
 
  .. cpp:function:: network_selection distance_lt(double d);
 
- Only select within given distance. This may enable more efficient sampling through an
+ Only select within a given distance. This may enable more efficient sampling through an
  internal spatial data structure.
 
  .. cpp:function:: network_selection distance_gt(double d);
 
- Only select if distance greater then given distance. This may enable more efficient sampling
+ Only select if the distance is greater than a given distance. This may enable more efficient sampling
  through an internal spatial data structure.
 
 
@@ -359,14 +368,14 @@ Interconnectivity
 
  .. cpp:member:: network_label_dict dict
 
- Label dictionary for named selecations and values.
+ Label dictionary for named selections and values.
 
 
 .. function:: generate_network_connections(recipe, context, decomp)
 
  Generate network connections from the network description in the recipe. Only generates connections 
- with local gids in the domain composition as target. Does not include connections from
- the "connections_on" recipe function.
+ with local gids in the domain composition as the target. Does not include connections from
+ the ``connections_on`` recipe function.
 
 .. function:: generate_network_connections(recipe)