Merge pull request #515 from genn-team/override_max_connections

Fix max connections issues
genn-team · Apr 28, 2022 · a53cbca · a53cbca
2 parents d941d60 + 17204e4
commit a53cbca
Show file tree

Hide file tree

Showing 2 changed files with 20 additions and 7 deletions.
diff --git a/src/genn/genn/code_generator/groupMerged.cc b/src/genn/genn/code_generator/groupMerged.cc
@@ -1258,10 +1258,9 @@ boost::uuids::detail::sha1::digest_type SynapseGroupMergedBase::getHashDigest(Ro
     // Update hash with number of neurons in pre and postsynaptic population
     updateHash([](const SynapseGroupInternal &g) { return g.getSrcNeuronGroup()->getNumNeurons(); }, hash);
     updateHash([](const SynapseGroupInternal &g) { return g.getTrgNeuronGroup()->getNumNeurons(); }, hash);
+    updateHash([](const SynapseGroupInternal &g) { return g.getMaxConnections(); }, hash);
     updateHash([](const SynapseGroupInternal &g) { return g.getMaxSourceConnections(); }, hash);
-    // **NOTE** ideally we'd include the row stride but this needs a backend and it SHOULDN'T be necessary
-    // as I can't think of any way of changing this without changing the hash in other places
-
+
     if(updateRole) {
         // Update hash with weight update model parameters and derived parameters
         updateHash([](const SynapseGroupInternal &g) { return g.getWUParams(); }, hash);

diff --git a/src/genn/genn/synapseGroup.cc b/src/genn/genn/synapseGroup.cc
@@ -146,8 +146,15 @@ void SynapseGroup::setMaxConnections(unsigned int maxConnections)
     }
     else {
         if(getMatrixType() & SynapseMatrixConnectivity::SPARSE) {
-            if(m_SparseConnectivityInitialiser.getSnippet()->getCalcMaxRowLengthFunc()) {
-                throw std::runtime_error("setMaxConnections: Synapse group already has max connections defined by sparse connectivity initialisation snippet.");
+            // If sparse connectivity initialiser provides a function to calculate max row length
+            auto calcMaxRowLengthFunc = m_SparseConnectivityInitialiser.getSnippet()->getCalcMaxRowLengthFunc();
+            if(calcMaxRowLengthFunc) {
+                // Call function and if max connections we specify is less than the bound imposed by the snippet, give error
+                auto connectivityMaxRowLength = calcMaxRowLengthFunc(getSrcNeuronGroup()->getNumNeurons(), getTrgNeuronGroup()->getNumNeurons(),
+                                                                     m_SparseConnectivityInitialiser.getParams());
+                if (maxConnections < connectivityMaxRowLength) {
+                    throw std::runtime_error("setMaxConnections: max connections must be higher than that already specified by sparse connectivity initialisation snippet.");
+                }
             }
 
             m_MaxConnections = maxConnections;
@@ -168,8 +175,15 @@ void SynapseGroup::setMaxSourceConnections(unsigned int maxConnections)
     }
     else {
         if(getMatrixType() & SynapseMatrixConnectivity::SPARSE) {
-            if(m_SparseConnectivityInitialiser.getSnippet()->getCalcMaxColLengthFunc()) {
-                throw std::runtime_error("setMaxSourceConnections: Synapse group already has max source connections defined by connectivity initialisation snippet.");
+            // If sparse connectivity initialiser provides a function to calculate max col length
+            auto calcMaxColLengthFunc = m_SparseConnectivityInitialiser.getSnippet()->getCalcMaxColLengthFunc();
+            if (calcMaxColLengthFunc) {
+                // Call function and if max connections we specify is less than the bound imposed by the snippet, give error
+                auto connectivityMaxColLength = calcMaxColLengthFunc(getSrcNeuronGroup()->getNumNeurons(), getTrgNeuronGroup()->getNumNeurons(),
+                                                                     m_SparseConnectivityInitialiser.getParams());
+                if (maxConnections < connectivityMaxColLength) {
+                    throw std::runtime_error("setMaxSourceConnections: max source connections must be higher than that already specified by sparse connectivity initialisation snippet.");
+                }
             }
 
             m_MaxSourceConnections = maxConnections;