abc_engine.py

import numpy as np
from dataclasses import dataclass, field
@dataclass
class Activity:
    name:str; cost:float; driver:str; volume:float
    @property
    def rate(s): return s.cost/max(s.volume,1e-8)
@dataclass
class Product:
    name:str; units:int; rev:float; dm:float; dl:float; usage:dict=field(default_factory=dict)
class ABCEngine:
    def __init__(s): s.acts,s.prods=[],[]
    def calc(s):
        res=[]
        for p in s.prods:
            oh=sum(p.usage.get(a.name,0)*a.rate for a in s.acts); tot=p.dm*p.units+p.dl*p.units+oh
            cpu=tot/max(p.units,1); m=p.rev-cpu
            res.append({"name":p.name,"cpu":round(cpu,2),"margin":round(m,2),"margin_pct":round(m/max(p.rev,1e-8)*100,1),"overhead":round(oh,2)})
        return res
    def whale(s):
        c=s.calc(); sc=sorted(c,key=lambda x:x["margin"]*1,reverse=True); tot=sum(x["margin"] for x in sc); cum=0
        return [{"product":x["name"],"cum_pct":round((cum:=cum+x["margin"])/max(tot,1e-8)*100,1)} for x in sc]
def demo():
    e=ABCEngine()
    e.acts=[Activity("Setup",120000,"setups",400),Activity("QC",80000,"inspections",2000),Activity("Handling",60000,"moves",5000)]
    e.prods=[Product("Standard",40000,25,8,3,{"Setup":50,"QC":400,"Handling":2000}),Product("Premium",5000,80,20,8,{"Setup":200,"QC":1000,"Handling":2000}),Product("Custom",1000,200,45,15,{"Setup":150,"QC":600,"Handling":1000})]
    for c in e.calc(): print(f"  {c['name']}: cost/unit=${c['cpu']}, margin={c['margin_pct']}%")
if __name__=="__main__": demo()