Implementation of SQRT

[zikajk]

Hi, I had to implement some functions, but unfortunately SQRT relies on the internal API.
What do you think about making them part of broch.core?

(defn pow [a b]
  (reduce b/* (repeat b a)))

(defn derive-sqrt-comp [x]
  (->> x
       b/composition
       (map (fn [[k v]] (if (= :broch/scaled k) 
                                     [k #?(:clj (rationalize (math/sqrt v))
                                         :cljs (math/sqrt v))] 
                                     [k (/ v 2)])))
       (into {})))
       
(defn sqrt [x]
  (let [result (math/sqrt (b/num x))
        composition (derive-sqrt-comp x)
        new-unit (get @broch.impl/composition-registry composition)]
    (when new-unit
      (broch.impl/quantity new-unit result))))

[2food]

Hi @zikajk.

We could add pow and sqrt to broch.core but as of now I'm not sure I see the need to. It would additionally require implementing sqrt for a JSRatio, and probably some more. I consider the arithmetic api of +,-,*, and / as "complete", since that's what most users will ever really need for calculations with units. Do have a specific use case where you needed this?

[zikajk]

Hi @2food,
My use is to support expressions like this:
10mm + (3m * pi()) ^ 2

You are probably right. I am still on "2023.12.15" where JSRatio doesn't exist yet.