diff --git a/kmath-polynomial/src/commonMain/kotlin/space/kscience/kmath/functions/collectionUtils.kt b/kmath-polynomial/src/commonMain/kotlin/space/kscience/kmath/functions/collectionUtils.kt
index ee32aa9a7..0d2ea3653 100644
--- a/kmath-polynomial/src/commonMain/kotlin/space/kscience/kmath/functions/collectionUtils.kt
+++ b/kmath-polynomial/src/commonMain/kotlin/space/kscience/kmath/functions/collectionUtils.kt
@@ -9,7 +9,13 @@ import kotlin.contracts.InvocationKind.*
 import kotlin.contracts.contract
 
 
-// TODO: Docs
+/**
+ * Computes the given lambda [compute] on value corresponding to the provided [key] or `null` if the key is not present.
+ *
+ * @param key key which corresponding value will be used if it's present.
+ * @param compute lambda that is computed on the received value.
+ * @return result of the computation of the lambda.
+ */
 internal inline fun <K, V, R> Map<in K, V>.computeOn(key: K, compute: (V?) -> R): R {
     contract {
         callsInPlace(compute, EXACTLY_ONCE)
@@ -17,7 +23,15 @@ internal inline fun <K, V, R> Map<in K, V>.computeOn(key: K, compute: (V?) -> R)
     return compute(get(key))
 }
 
-// TODO: Docs
+/**
+ * Computes the given lambda [compute] on value corresponding to the provided [key] or computes the given lambda
+ * [defaultResult] if the key is not present.
+ *
+ * @param key key which corresponding value will be used if it's present.
+ * @param compute lambda that is computed on the value corresponding to the [key].
+ * @param defaultResult lambda that is computed if the [key] is not present.
+ * @return result of [compute] lambda if the [key] is present or result of [defaultResult] otherwise.
+ */
 internal inline fun <K, V, R> Map<K, V>.computeOnOrElse(key: K, defaultResult: () -> R, compute: (value: V) -> R): R {
     contract {
         callsInPlace(defaultResult, AT_MOST_ONCE)
@@ -27,7 +41,15 @@ internal inline fun <K, V, R> Map<K, V>.computeOnOrElse(key: K, defaultResult: (
     return (if (key !in this) defaultResult() else compute(get(key) as V))
 }
 
-// TODO: Docs
+/**
+ * Computes the given lambda [compute] on value corresponding to the provided [key] or computes the given lambda
+ * [defaultResult] if the key is not present.
+ *
+ * @param key key which corresponding value will be used if it's present.
+ * @param compute lambda that is computed on the value corresponding to the [key].
+ * @param defaultResult default result that is returned in case of the [key]'s absence.
+ * @return result of [compute] lambda if the [key] is present or [defaultResult] otherwise.
+ */
 internal inline fun <K, V, R> Map<K, V>.computeOnOrElse(key: K, defaultResult: R, compute: (value: V) -> R): R {
     contract {
         callsInPlace(compute, AT_MOST_ONCE)
@@ -35,7 +57,15 @@ internal inline fun <K, V, R> Map<K, V>.computeOnOrElse(key: K, defaultResult: R
     return computeOnOrElse(key, { defaultResult }, compute)
 }
 
-// TODO: Docs
+/**
+ * Computes the given lambda [compute] on value corresponding to the provided [key] or computes the given lambda
+ * [defaultResult] if the key is not present.
+ *
+ * @param key key which corresponding value will be used if it's present.
+ * @param compute lambda that is computed on the value corresponding to the [key].
+ * @param defaultResult default result that is returned in case of the [key]'s absence.
+ * @return result of [compute] lambda if the [key] is present or [defaultResult] otherwise.
+ */
 internal inline fun <K, V, R> Map<K, V>.computeOnOrElse(key: K, defaultResult: R, compute: (key: K, value: V) -> R): R {
     contract {
         callsInPlace(compute, AT_MOST_ONCE)
@@ -374,8 +404,20 @@ internal inline fun <K, V, W, D: MutableMap<K, W>> Map<out K, V>.copyMapToBy(des
 internal inline fun <K, V, W, D: MutableMap<K, W>> Map<out K, V>.copyMapToBy(destination: D, transform: (key: K, value: V) -> W, resolve: (currentValue: W, newValue: V) -> W): D =
     copyMapToBy(destination, { (key, value) -> transform(key, value) }, { _, currentValue, newValue -> resolve(currentValue, newValue) })
 
-// TODO: Docs
-internal fun <K, V, D: MutableMap<K, V>> mergeTo(map1: Map<out K, V>, map2: Map<out K, V>, destination: D): D {
+/**
+ * Merges [the first map][map1] and [the second map][map2] prioritising the second one, puts result to the [destination]
+ * and returns the [destination].
+ *
+ * Precisely, corresponding keys and values of the received maps are put into the destination overriding existing values
+ * in the [destination] if needed. For every key appearing in both maps corresponding value from the second map is
+ * chosen.
+ *
+ * @param map1 the first (less prioritised) map to merge.
+ * @param map2 the second (more prioritised) map to merge.
+ * @param destination the map where result of the merge is put.
+ * @return the destination.
+ */
+internal fun <K, V, D: MutableMap<in K, in V>> mergeTo(map1: Map<out K, V>, map2: Map<out K, V>, destination: D): D {
     for ((key, value) in map1) {
         destination.put(key, value)
     }
@@ -385,7 +427,20 @@ internal fun <K, V, D: MutableMap<K, V>> mergeTo(map1: Map<out K, V>, map2: Map<
     return destination
 }
 
-// TODO: Docs
+/**
+ * Merges [the first map][map1] and [the second map][map2] resolving conflicts with [resolve] lambda, puts result to the
+ * [destination] and returns the [destination].
+ *
+ * Precisely, corresponding keys and values of the received maps are put into the destination overriding existing values
+ * in the [destination] if needed. For every key appearing in both maps corresponding value is a result of the [resolve]
+ * lambda calculated on the key and its corresponding values from the merged maps.
+ *
+ * @param map1 the first (less prioritised) map to merge.
+ * @param map2 the second (more prioritised) map to merge.
+ * @param resolve lambda function that resolves merge conflicts.
+ * @param destination the map where result of the merge is put.
+ * @return the destination.
+ */
 internal inline fun <K, V1: W, V2: W, W, D: MutableMap<K, W>> mergeToBy(map1: Map<out K, V1>, map2: Map<out K, V2>, destination: D, resolve: (key: K, value1: V1, value2: V2) -> W): D {
     for (key in map2.keys) {
         destination.remove(key)
@@ -400,27 +455,82 @@ internal inline fun <K, V1: W, V2: W, W, D: MutableMap<K, W>> mergeToBy(map1: Ma
     return destination
 }
 
-// TODO: Docs
+/**
+ * Merges [the first map][map1] and [the second map][map2] resolving conflicts with [resolve] lambda, puts result to the
+ * [destination] and returns the [destination].
+ *
+ * Precisely, corresponding keys and values of the received maps are put into the destination overriding existing values
+ * in the [destination] if needed. For every key appearing in both maps corresponding value is a result of the [resolve]
+ * lambda calculated on the key's corresponding values from the merged maps.
+ *
+ * @param map1 the first (less prioritised) map to merge.
+ * @param map2 the second (more prioritised) map to merge.
+ * @param resolve lambda function that resolves merge conflicts.
+ * @param destination the map where result of the merge is put.
+ * @return the destination.
+ */
 internal inline fun <K, V1: W, V2: W, W, D: MutableMap<K, W>> mergeToBy(map1: Map<K, V1>, map2: Map<K, V2>, destination: D, resolve: (value1: V1, value2: V2) -> W): D =
     mergeToBy(map1, map2, destination) { _, value1, value2 -> resolve(value1, value2) }
 
-// TODO: Docs
+/**
+ * Merges [the first map][map1] and [the second map][map2] prioritising the second one.
+ *
+ * Precisely, corresponding keys and values of the received maps are put into a new empty map which is returned after
+ * afterwards. For every key appearing in both maps corresponding value from the second map is chosen.
+ *
+ * @param map1 the first (less prioritised) map to merge.
+ * @param map2 the second (more prioritised) map to merge.
+ * @return the result of the merge.
+ */
 internal fun <K, V1: W, V2: W, W> merge(map1: Map<K, V1>, map2: Map<K, V2>): Map<K, W> {
     val result = LinkedHashMap<K, W>(map1.size + map2.size)
     return mergeTo(map1, map2, result)
 }
 
-// TODO: Docs
-internal inline fun <K, V1: W, V2: W, W> mergeBy(map1: Map<K, V1>, map2: Map<K, V2>, transform: (key: K, value1: V1, value2: V2) -> W): Map<K, W> {
+/**
+ * Merges [the first map][map1] and [the second map][map2] resolving conflicts with [resolve] lambda.
+ *
+ * Precisely, corresponding keys and values of the received maps are put into a new empty map which is returned after
+ * afterwards. For every key appearing in both maps corresponding value is a result of the [resolve] lambda calculated
+ * on the key and its corresponding values from the merged maps.
+ *
+ * @param map1 the first (less prioritised) map to merge.
+ * @param map2 the second (more prioritised) map to merge.
+ * @param resolve lambda function that resolves merge conflicts.
+ * @return the result of the merge.
+ */
+internal inline fun <K, V1: W, V2: W, W> mergeBy(map1: Map<K, V1>, map2: Map<K, V2>, resolve: (key: K, value1: V1, value2: V2) -> W): Map<K, W> {
     val result = LinkedHashMap<K, W>(map1.size + map2.size)
-    return mergeToBy(map1, map2, result, transform)
+    return mergeToBy(map1, map2, result, resolve)
 }
 
-// TODO: Docs
-internal inline fun <K, V1: W, V2: W, W> mergeBy(map1: Map<K, V1>, map2: Map<K, V2>, transform: (value1: V1, value2: V2) -> W): Map<K, W> =
-    mergeBy(map1, map2) { _, value1, value2 -> transform(value1, value2) }
+/**
+ * Merges [the first map][map1] and [the second map][map2] resolving conflicts with [resolve] lambda.
+ *
+ * Precisely, corresponding keys and values of the received maps are put into a new empty map which is returned after
+ * afterwards. For every key appearing in both maps corresponding value is a result of the [resolve] lambda calculated
+ * on the key's corresponding values from the merged maps.
+ *
+ * @param map1 the first (less prioritised) map to merge.
+ * @param map2 the second (more prioritised) map to merge.
+ * @param resolve lambda function that resolves merge conflicts.
+ * @return the result of the merge.
+ */
+internal inline fun <K, V1: W, V2: W, W> mergeBy(map1: Map<K, V1>, map2: Map<K, V2>, resolve: (value1: V1, value2: V2) -> W): Map<K, W> =
+    mergeBy(map1, map2) { _, value1, value2 -> resolve(value1, value2) }
 
-// TODO: Docs
+/**
+ * Populates the [destination] map with key-value pairs provided by [transform] function applied to each element of the
+ * given collection resolving conflicts with [resolve] function and returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each element to key-value.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <T, K, V, D : MutableMap<K, V>> Iterable<T>.associateTo(destination: D, transform: (T) -> Pair<K, V>, resolve: (key: K, currentValue: V, newValue: V) -> V): D {
     for (element in this) {
         val (key, value) = transform(element)
@@ -429,7 +539,20 @@ internal inline fun <T, K, V, D : MutableMap<K, V>> Iterable<T>.associateTo(dest
     return destination
 }
 
-// TODO: Docs
+/**
+ * Populates the [destination] map with key-value pairs, where key is provided by [keySelector] function and value is
+ * provided by [valueTransform] applied to each element of the given collection, resolving conflicts with [resolve]
+ * function and returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param valueTransform lambda functions that generates value for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <T, K, V, D : MutableMap<K, V>> Iterable<T>.associateByTo(destination: D, keySelector: (T) -> K, valueTransform: (T) -> V, resolve: (key: K, currentValue: V, newValue: V) -> V): D {
     for (element in this) {
         val key = keySelector(element)
@@ -439,7 +562,19 @@ internal inline fun <T, K, V, D : MutableMap<K, V>> Iterable<T>.associateByTo(de
     return destination
 }
 
-// TODO: Docs
+/**
+ * Populates the [destination] map with key-value pairs, where key is provided by [keySelector] function applied to each
+ * element of the given collection and value is the element itself, resolving conflicts with [resolve] function and
+ * returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <T, K, D : MutableMap<K, T>> Iterable<T>.associateByTo(destination: D, keySelector: (T) -> K, resolve: (key: K, currentValue: T, newValue: T) -> T): D {
     for (element in this) {
         val key = keySelector(element)
@@ -448,86 +583,324 @@ internal inline fun <T, K, D : MutableMap<K, T>> Iterable<T>.associateByTo(desti
     return destination
 }
 
-// TODO: Docs
+/**
+ * Populates the [destination] map with key-value pairs provided by [transform] function applied to each element of the
+ * given collection resolving conflicts with [resolve] function and returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each element to key-value pair.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <T, K, V, D : MutableMap<K, V>> Iterable<T>.associateTo(destination: D, transform: (T) -> Pair<K, V>, resolve: (currentValue: V, newValue: V) -> V): D =
     associateTo(destination, transform) { _, currentValue, newValue -> resolve(currentValue, newValue) }
 
-// TODO: Docs
+/**
+ * Populates the [destination] map with key-value pairs, where key is provided by [keySelector] function and value is
+ * provided by [valueTransform] applied to each element of the given collection, resolving conflicts with [resolve]
+ * function and returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param valueTransform lambda functions that generates value for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <T, K, V, D : MutableMap<K, V>> Iterable<T>.associateByTo(destination: D, keySelector: (T) -> K, valueTransform: (T) -> V, resolve: (currentValue: V, newValue: V) -> V): D =
     associateByTo(destination, keySelector, valueTransform) { _, currentValue, newValue -> resolve(currentValue, newValue) }
 
-// TODO: Docs
+/**
+ * Populates the [destination] map with key-value pairs, where key is provided by [keySelector] function applied to each
+ * element of the given collection and value is the element itself, resolving conflicts with [resolve] function and
+ * returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <T, K, D : MutableMap<K, T>> Iterable<T>.associateByTo(destination: D, keySelector: (T) -> K, resolve: (currentValue: T, newValue: T) -> T): D =
     associateByTo(destination, keySelector) { _, currentValue, newValue -> resolve(currentValue, newValue) }
 
-// TODO: Docs
+/**
+ * Returns a map containing key-value pairs provided by [transform] function applied to elements of the given collection.
+ *
+ * All pairs are added in order of iteration. If some key is already added to the map, adding new key-value pair with the
+ * key is resolved with [resolve] function which takes the key, current value corresponding to the key, and new value
+ * from the pair.
+ *
+ * @param transform function which transforms each element to key-value pair.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <T, K, V> Iterable<T>.associate(transform: (T) -> Pair<K, V>, resolve: (key: K, currentValue: V, newValue: V) -> V): Map<K, V> =
     associateTo(LinkedHashMap(), transform, resolve)
 
-// TODO: Docs
+/**
+ * Returns a map containing the values provided by [valueTransform] and indexed by [keySelector] functions applied to
+ * elements of the given collection.
+ *
+ * All pairs are added in order of iteration. If some key is already added to the map, adding new key-value pair with
+ * the key is resolved with [resolve] function which takes the key, current value corresponding to the key, and new
+ * value from the pair.
+ *
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param valueTransform lambda functions that generates value for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <T, K, V> Iterable<T>.associateBy(keySelector: (T) -> K, valueTransform: (T) -> V, resolve: (key: K, currentValue: V, newValue: V) -> V): Map<K, V> =
     associateByTo(LinkedHashMap(), keySelector, valueTransform, resolve)
 
-// TODO: Docs
+/**
+ * Returns a map containing the elements from the given collection indexed by the key returned from [keySelector]
+ * function applied to each element.
+ *
+ * All pairs are added in order of iteration. If some key is already added to the map, adding new key-value pair with
+ * the key is resolved with [resolve] function which takes the key, current value corresponding to the key, and new
+ * value from the pair.
+ *
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <T, K> Iterable<T>.associateBy(keySelector: (T) -> K, resolve: (key: K, currentValue: T, newValue: T) -> T): Map<K, T> =
     associateByTo(LinkedHashMap(), keySelector, resolve)
 
-// TODO: Docs
+/**
+ * Returns a map containing key-value pairs provided by [transform] function applied to elements of the given collection.
+ *
+ * All pairs are added in order of iteration. If some key is already added to the map, adding new key-value pair with
+ * the key is resolved with [resolve] function which takes current value corresponding to the key and new value from the
+ * pair.
+ *
+ * @param transform function which transforms each element to key-value pair.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <T, K, V> Iterable<T>.associate(transform: (T) -> Pair<K, V>, resolve: (currentValue: V, newValue: V) -> V): Map<K, V> =
     associateTo(LinkedHashMap(), transform, resolve)
 
-// TODO: Docs
+/**
+ * Returns a map containing the values provided by [valueTransform] and indexed by [keySelector] functions applied to
+ * elements of the given collection.
+ *
+ * All pairs are added in order of iteration. If some key is already added to the map, adding new key-value pair with
+ * the key is resolved with [resolve] function which takes current value corresponding to the key and new value from the
+ * pair.
+ *
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param valueTransform lambda functions that generates value for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <T, K, V> Iterable<T>.associateBy(keySelector: (T) -> K, valueTransform: (T) -> V, resolve: (currentValue: V, newValue: V) -> V): Map<K, V> =
     associateByTo(LinkedHashMap(), keySelector, valueTransform, resolve)
 
-// TODO: Docs
+/**
+ * Returns a map containing the elements from the given collection indexed by the key returned from [keySelector]
+ * function applied to each element.
+ *
+ * All pairs are added in order of iteration. If some key is already added to the map, adding new key-value pair with
+ * the key is resolved with [resolve] function which takes current value corresponding to the key and new value from the
+ * pair.
+ *
+ * @param keySelector lambda functions that generates keys for the key-value pairs.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <T, K> Iterable<T>.associateBy(keySelector: (T) -> K, resolve: (currentValue: T, newValue: T) -> T): Map<K, T> =
     associateByTo(LinkedHashMap(), keySelector, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys of this map and the values obtained
+ * by applying the [transform] function to each entry in this map resolving conflicts with [resolve] function and
+ * returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new value.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <K, V, W, D : MutableMap<K, W>> Map<out K, V>.mapValuesTo(destination: D, transform: (Map.Entry<K, V>) -> W, resolve: (key: K, currentValue: W, newValue: W) -> W): D =
     entries.associateByTo(destination, { it.key }, transform, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys of this map and the values obtained
+ * by applying the [transform] function to each entry in this map resolving conflicts with [resolve] function and
+ * returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new value.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <K, V, W, D : MutableMap<K, W>> Map<out K, V>.mapValuesTo(destination: D, transform: (key: K, value: V) -> W, resolve: (key: K, currentValue: W, newValue: W) -> W): D =
     entries.associateByTo(destination, { it.key }, { (key, value) -> transform(key, value) }, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys of this map and the values obtained
+ * by applying the [transform] function to each entry in this map resolving conflicts with [resolve] function and
+ * returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new value.
+ * @param resolve lambda function that resolves merge conflicts which current and new values corresponding to some key.
+ * @return the [destination].
+ */
 internal inline fun <K, V, W, D : MutableMap<K, W>> Map<out K, V>.mapValuesTo(destination: D, transform: (Map.Entry<K, V>) -> W, resolve: (currentValue: W, newValue: W) -> W): D =
     entries.associateByTo(destination, { it.key }, transform, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys of this map and the values obtained
+ * by applying the [transform] function to each entry in this map resolving conflicts with [resolve] function and
+ * returns the [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new value.
+ * @param resolve lambda function that resolves merge conflicts which current and new values corresponding to some key.
+ * @return the [destination].
+ */
 internal inline fun <K, V, W, D : MutableMap<K, W>> Map<out K, V>.mapValuesTo(destination: D, transform: (key: K, value: V) -> W, resolve: (currentValue: W, newValue: W) -> W): D =
     entries.associateByTo(destination, { it.key }, { (key, value) -> transform(key, value) }, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys obtained by applying the [transform] function to
+ * each entry in this map and the values of this map, resolving conflicts with [resolve] function and returns the
+ * [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <K, V, L, D : MutableMap<L, V>> Map<out K, V>.mapKeysTo(destination: D, transform: (Map.Entry<K, V>) -> L, resolve: (key: L, currentValue: V, newValue: V) -> V): D =
     entries.associateByTo(destination, transform, { it.value }, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys obtained by applying the [transform] function to
+ * each entry in this map and the values of this map, resolving conflicts with [resolve] function and returns the
+ * [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the [destination].
+ */
 internal inline fun <K, V, L, D : MutableMap<L, V>> Map<out K, V>.mapKeysTo(destination: D, transform: (key: K, value: V) -> L, resolve: (key: L, currentValue: V, newValue: V) -> V): D =
     entries.associateByTo(destination, { (key, value) -> transform(key, value) }, { it.value }, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys obtained by applying the [transform] function to
+ * each entry in this map and the values of this map, resolving conflicts with [resolve] function and returns the
+ * [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which current and new values corresponding to some key.
+ * @return the [destination].
+ */
 internal inline fun <K, V, L, D : MutableMap<L, V>> Map<out K, V>.mapKeysTo(destination: D, transform: (Map.Entry<K, V>) -> L, resolve: (currentValue: V, newValue: V) -> V): D =
     entries.associateByTo(destination, transform, { it.value }, resolve)
 
-// TODO: Docs
+/**
+ * Populates the given [destination] map with entries having the keys obtained by applying the [transform] function to
+ * each entry in this map and the values of this map, resolving conflicts with [resolve] function and returns the
+ * [destination].
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param destination the destination of the generated key-value pairs.
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which current and new values corresponding to some key.
+ * @return the [destination].
+ */
 internal inline fun <K, V, L, D : MutableMap<L, V>> Map<out K, V>.mapKeysTo(destination: D, transform: (key: K, value: V) -> L, resolve: (currentValue: V, newValue: V) -> V): D =
     entries.associateByTo(destination, { (key, value) -> transform(key, value) }, { it.value }, resolve)
 
-// TODO: Docs
+/**
+ * Returns a new map with entries having the keys obtained by applying the [transform] function to each entry in this
+ * map and the values of this map and resolving conflicts with [resolve] function.
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <K, V, L> Map<out K, V>.mapKeys(transform: (Map.Entry<K, V>) -> L, resolve: (key: L, currentValue: V, newValue: V) -> V): Map<L, V> =
     mapKeysTo(LinkedHashMap(size), transform, resolve)
 
-// TODO: Docs
+/**
+ * Returns a new map with entries having the keys obtained by applying the [transform] function to each entry in this
+ * map and the values of this map and resolving conflicts with [resolve] function.
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which receives some key, its current, and new
+ * corresponding values.
+ * @return the result map.
+ */
 internal inline fun <K, V, L> Map<out K, V>.mapKeys(transform: (key: K, value: V) -> L, resolve: (key: L, currentValue: V, newValue: V) -> V): Map<L, V> =
     mapKeysTo(LinkedHashMap(size), transform, resolve)
 
-// TODO: Docs
+/**
+ * Returns a new map with entries having the keys obtained by applying the [transform] function to each entry in this
+ * map and the values of this map and resolving conflicts with [resolve] function.
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which current and new values corresponding to some key.
+ * @return the result map.
+ */
 internal inline fun <K, V, L> Map<out K, V>.mapKeys(transform: (Map.Entry<K, V>) -> L, resolve: (currentValue: V, newValue: V) -> V): Map<L, V> =
     mapKeysTo(LinkedHashMap(size), transform, resolve)
 
-// TODO: Docs
+/**
+ * Returns a new map with entries having the keys obtained by applying the [transform] function to each entry in this
+ * map and the values of this map and resolving conflicts with [resolve] function..
+ *
+ * All pairs are added and resolved in order of iteration.
+ *
+ * @param transform function which transforms each key-value pair to new key.
+ * @param resolve lambda function that resolves merge conflicts which current and new values corresponding to some key.
+ * @return the result map.
+ */
 internal inline fun <K, V, L> Map<out K, V>.mapKeys(transform: (key: K, value: V) -> L, resolve: (currentValue: V, newValue: V) -> V): Map<L, V> =
     mapKeysTo(LinkedHashMap(size), transform, resolve)
\ No newline at end of file