ENH(plot,arch): link Legend to arch + tooltips; ...

+ doc(arch): x2 terms: sideffects, eviction
+ DROP(plot): `graphop` from Legend.

Author: ankostis

docs/GraphtikFlowchart.dot

@@ -7,36 +7,36 @@ digraph {
     labelloc=t;
 
     operations  [shape=parallelogram fontname="italic" tooltip=class
-                 URL="#term-operation"];
+                 URL="arch.html#term-operation"];
     compose     [fontname="italic" tooltip=phase
-                 URL="#term-composition"];
+                 URL="arch.html#term-composition"];
     network     [shape=parallelogram fontname="italic" tooltip=class
-                 URL="#term-network"];
+                 URL="arch.html#term-network"];
     inputs      [shape=rect label="input names" tooltip=mappings
-                 URL="#term-inputs"];
+                 URL="arch.html#term-inputs"];
     outputs     [shape=rect label="output names" tooltip=mappings
-                 URL="#term-outputs"];
+                 URL="arch.html#term-outputs"];
     predicate   [shape=rect label="node predicate" tooltip=function
-                 URL="#term-node-predicate"];
+                 URL="arch.html#term-node-predicate"];
     subgraph cluster_compute {
         label=compute
         fontname=bold
         style=dashed
         labelloc=b
         tooltip="process, NetOp's method"
-        URL="#term-compute"
+        URL="arch.html#term-compute"
 
         compile     [fontname="italic" tooltip="phase, Network's method"
-                     URL="#term-compilation"];
+                     URL="arch.html#term-compilation"];
         plan        [shape=parallelogram label="execution plan" fontname="italic" tooltip=class
-                     URL="#term-execution-plan"];
+                     URL="arch.html#term-execution-plan"];
         execute     [fontname=italic fontname="italic" tooltip="phase, Plan's method"
-                     URL="#term-execution"];
+                     URL="arch.html#term-execution"];
     }
     values      [shape=rect label="input values" tooltip=mappings
-                 URL="#term-inputs"];
+                 URL="arch.html#term-inputs"];
     solution    [shape=parallelogram tooltip=class
-                 URL="#term-solution"];
+                 URL="arch.html#term-solution"];
 
     operations -> compose -> network    [arrowhead=vee];
     {network inputs outputs predicate} -> compile -> plan  [arrowhead=vee];

docs/source/arch.rst

@@ -91,14 +91,17 @@ Architecture
         It is built by :meth:`.Network._build_execution_steps()` based on
         the subgraph `dag`.
 
-        There is a single type of *instruction*, :class:`_EvictInstruction`:,
-        which evicts items from `solution` as soon as they are not needed
-        further down the dag, to reduce memory footprint while computing.
+        The only *instruction* step is for performing `eviction`.
+
+    evict
+    eviction
+        The :class:`_EvictInstruction` `steps` erase items from
+        `solution` as soon as they are not needed further down the dag,
+        to reduce memory footprint while computing.
 
     solution
         A :class:`.Solution` created internally by :meth:`.NetworkOperation.compute()`
-        to hold the values of the `inputs`, and those of the generated
-        (intermediate and possibly overwritten) `outputs`.
+        to hold the values both `inputs` & `outputs`, and the status of *executed* operations.
         It is based on a :class:`collections.ChainMap`, to keep one dictionary
         for each `operation` executed +1 for inputs.
 
@@ -129,7 +132,8 @@ Architecture
 
     plan
     execution plan
-        Class :class:`.ExecutionPlan` perform the `execution` phase.
+        Class :class:`.ExecutionPlan` perform the `execution` phase which contains
+        the `dag` and the `steps`.
 
         `Compile`\ed *execution plans* are cached in :attr:`.Network._cached_plans`
         across runs with (`inputs`, `outputs`, `predicate`) as key.
@@ -152,13 +156,19 @@ Architecture
         The :class:`.NetworkOperation` class holding a `network` of `operation`\s.
 
     needs
-        A list of names of the compulsory/optional values an operation's
+        A list of names of the compulsory/optional values or `sideffects` an operation's
         underlying callable requires to execute.
 
     provides
         A list of names of the values produced when the `operation`'s
         underlying callable executes.
 
+    sideffects
+        Fictive `needs` or `provides` not consumed/produced by the underlying function
+        of an `operation`, annotated with :class:`.sideffect`.
+        A *sideffect* participates in the solution of the graph but is never
+        given/asked to/from functions.
+
     prune
     pruning
         Method :meth:`.Network._prune_graph()` extracts a subgraph `dag` that