Optimizer interface and sample implementation (#19)

Reviewed-on: Rubydragon/MetagraphOptimization.jl#19
Co-authored-by: Anton Reinhard <anton.reinhard@proton.me>
Co-committed-by: Anton Reinhard <anton.reinhard@proton.me>

src/operation/validate.jl

@@ -54,9 +54,9 @@ function is_valid_node_reduction_input(graph::DAG, nodes::Vector{Node})
         @assert is_valid(graph, n)
     end
 
-    t = typeof(nodes[1].task)
+    t = typeof(task(nodes[1]))
     for n in nodes
-        if typeof(n.task) != t
+        if typeof(task(n)) != t
             throw(AssertionError("[Node Reduction] The given nodes are not of the same type"))
         end
 
@@ -115,7 +115,7 @@ Intended for use with `@assert` or `@test`.
 """
 function is_valid(graph::DAG, nr::NodeReduction)
     @assert is_valid_node_reduction_input(graph, nr.input)
-    @assert nr in graph.possibleOperations.nodeReductions "NodeReduction is not part of the graph's possible operations!"
+    #@assert nr in graph.possibleOperations.nodeReductions "NodeReduction is not part of the graph's possible operations!"
     return true
 end
 
@@ -128,7 +128,7 @@ Intended for use with `@assert` or `@test`.
 """
 function is_valid(graph::DAG, ns::NodeSplit)
     @assert is_valid_node_split_input(graph, ns.input)
-    @assert ns in graph.possibleOperations.nodeSplits "NodeSplit is not part of the graph's possible operations!"
+    #@assert ns in graph.possibleOperations.nodeSplits "NodeSplit is not part of the graph's possible operations!"
     return true
 end
 
@@ -141,6 +141,6 @@ Intended for use with `@assert` or `@test`.
 """
 function is_valid(graph::DAG, nf::NodeFusion)
     @assert is_valid_node_fusion_input(graph, nf.input[1], nf.input[2], nf.input[3])
-    @assert nf in graph.possibleOperations.nodeFusions "NodeFusion is not part of the graph's possible operations!"
+    #@assert nf in graph.possibleOperations.nodeFusions "NodeFusion is not part of the graph's possible operations!"
     return true
 end