diff --git a/core/src/main/java/org/nwapw/abacus/plugin/PluginManager.java b/core/src/main/java/org/nwapw/abacus/plugin/PluginManager.java
index 3d4f384..27404d4 100644
--- a/core/src/main/java/org/nwapw/abacus/plugin/PluginManager.java
+++ b/core/src/main/java/org/nwapw/abacus/plugin/PluginManager.java
@@ -141,6 +141,7 @@ public class PluginManager {
         registeredNumberImplementations.put(name, implementation);
         interfaceImplementationNames.put(implementation.getImplementation(), name);
         interfaceImplementations.put(implementation.getImplementation(), implementation);
+        cachedPi.put(implementation.getImplementation(), implementation.instanceForPi());
     }
 
     /**
@@ -218,10 +219,6 @@ public class PluginManager {
                 break;
             }
         }
-        if (toReturn == null) {
-            toReturn = new Documentation(name, "", "", "", type);
-            registerDocumentation(toReturn);
-        }
         return toReturn;
     }
 
@@ -252,14 +249,7 @@ public class PluginManager {
      * @return pi
      */
     public NumberInterface piFor(Class<? extends NumberInterface> forClass) {
-        if (cachedPi.containsKey(forClass)) return cachedPi.get(forClass);
-        NumberImplementation implementation = interfaceImplementationFor(forClass);
-        NumberInterface generatedPi = null;
-        if (implementation != null) {
-            generatedPi = implementation.instanceForPi();
-        }
-        cachedPi.put(forClass, generatedPi);
-        return generatedPi;
+        return cachedPi.get(forClass);
     }
 
     /**
diff --git a/core/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java b/core/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
index edaa3a5..3d20019 100755
--- a/core/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
+++ b/core/src/main/java/org/nwapw/abacus/plugin/StandardPlugin.java
@@ -693,8 +693,7 @@ public class StandardPlugin extends Plugin {
      * @param n              non-negative integer.
      * @return a number of numClass with value n factorial.
      */
-    public static NumberInterface factorial(NumberImplementation implementation, int n) {
-
+    synchronized public static NumberInterface factorial(NumberImplementation implementation, int n) {
         if (!FACTORIAL_LISTS.containsKey(implementation)) {
             FACTORIAL_LISTS.put(implementation, new ArrayList<>());
             FACTORIAL_LISTS.get(implementation).add(implementation.instanceForString("1"));
diff --git a/core/src/main/kotlin/org/nwapw/abacus/number/PromotionManager.kt b/core/src/main/kotlin/org/nwapw/abacus/number/PromotionManager.kt
index 421d642..a49a61c 100644
--- a/core/src/main/kotlin/org/nwapw/abacus/number/PromotionManager.kt
+++ b/core/src/main/kotlin/org/nwapw/abacus/number/PromotionManager.kt
@@ -37,21 +37,6 @@ class PromotionManager(val abacus: Abacus) : PluginListener {
         return null
     }
 
-    /**
-     * If a path between the given implementations has already been computed, uses
-     * the already calculated path. Otherwise, calls [computePathBetween] to compute a new
-     * path.
-     *
-     * @param from the implementation to start from.
-     * @param to the implementation to get to.
-     * @return the resulting promotion path, or null if it is not found
-     */
-    fun getPathBetween(from: NumberImplementation, to: NumberImplementation): PromotionPath? {
-        return computePaths.computeIfAbsent(from to to, {
-             computePathBetween(it.first, it.second)
-        })
-    }
-
     /**
      * Promote all the numbers in the list to the same number implementation, to ensure
      * they can be used with each other. Finds the highest priority implementation
@@ -66,16 +51,26 @@ class PromotionManager(val abacus: Abacus) : PluginListener {
         val highestPriority = implementations.sortedBy { it.priority }.last()
         return PromotionResult(items = numbers.map {
             if(it.javaClass == highestPriority.implementation) it
-            else getPathBetween(pluginManager.interfaceImplementationFor(it.javaClass), highestPriority)
+            else computePaths[pluginManager.interfaceImplementationFor(it.javaClass) to highestPriority]
                     ?.promote(it) ?: return null
         }.toTypedArray(), promotedTo = highestPriority)
     }
 
-    override fun onLoad(manager: PluginManager?) {
+    override fun onLoad(manager: PluginManager) {
+        val implementations = manager.allNumberImplementations.map { manager.numberImplementationFor(it) }
+        for((index, value) in implementations.withIndex()){
+            for(i in index until implementations.size){
+                val other = implementations[i]
 
+                val promoteFrom = if(other.priority > value.priority) value else other
+                val promoteTo = if(other.priority > value.priority) other else value
+                val path = computePathBetween(promoteFrom, promoteTo)
+                computePaths.put(promoteFrom to promoteTo, path)
+            }
+        }
     }
 
-    override fun onUnload(manager: PluginManager?) {
+    override fun onUnload(manager: PluginManager) {
         computePaths.clear()
     }
 
diff --git a/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java b/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java
index 1f50424..f903618 100644
--- a/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java
+++ b/fx/src/main/java/org/nwapw/abacus/fx/AbacusController.java
@@ -361,7 +361,12 @@ public class AbacusController implements PluginListener {
             enabledPlugins.add(plugin);
         }
         PluginManager pluginManager = abacus.getPluginManager();
-        functionList.addAll(manager.getAllFunctions().stream().map(name -> pluginManager.documentationFor(name, DocumentationType.FUNCTION))
+        functionList.addAll(manager.getAllFunctions().stream().map(name -> {
+            Documentation documentationInstance = pluginManager.documentationFor(name, DocumentationType.FUNCTION);
+            if(documentationInstance == null)
+                documentationInstance = new Documentation(name, "", "", "", DocumentationType.FUNCTION);
+            return documentationInstance;
+        })
                 .collect(Collectors.toCollection(ArrayList::new)));
         functionList.addAll(manager.getAllTreeValueFunctions().stream().map(name -> pluginManager.documentationFor(name, DocumentationType.TREE_VALUE_FUNCTION))
                 .collect(Collectors.toCollection(ArrayList::new)));