I’ve been trying to fix this issue but chat gpt ke...

python
import math, numpy as np, collections, itertools

def hold_of(p):
    q=1-p
    return p**4*(1+4*q+10*q*q)+20*p**3*q**3*((p*p)/(p*p+q*q))
def server_at_point(first,idx):
    if idx==0: return first
    block=(idx-1)//2
    return ('B' if first=='A' else 'A') if block%2==0 else first
def tb_win(spwA, spwB, first, target=7):
    active={(0,0,0):1.0}; win=0
    for step in range(240):
        nxt=collections.defaultdict(float); mass=0
        for (a,b,idx), pr in active.items():
            srv=server_at_point(first,idx)
            pA=spwA if srv=='A' else 1-spwB
            a1,b1=a+1,b
            pa=pr*pA
            if a1>=target and a1-b1>=2: win+=pa
            else: nxt[(a1,b1,idx+1)]+=pa; mass+=pa
            a1,b1=a,b+1
            pb=pr*(1-pA)
            if not (b1>=target and b1-a1>=2):
                nxt[(a1,b1,idx+1)]+=pb; mass+=pb
        active=nxt
        if mass<1e-14: break
    rem=sum(active.values())
    if rem:
        win+=sum(pr for (a,b,idx),pr in active.items() if a>b)
    return win
from functools import lru_cache
@lru_cache(None)
def set_dist(spwA_r, spwB_r, start):
    spwA=float(spwA_r); spwB=float(spwB_r)
    hA=hold_of(spwA); hB=hold_of(spwB)
    active={(0,0,start):1.0}; out=collections.defaultdict(float)
    for loop in range(20):
        nxt=collections.defaultdict(float); any_=False
        for (ga,gb,srv),pr in active.items():
            if ga==6 and gb==6:
                tba=tb_win(spwA,spwB,srv,7)
                ns='B' if srv=='A' else 'A'
                out[(7,6,ns)]+=pr*tba
                out[(6,7,ns)]+=pr*(1-tba)
                continue
            pAG=hA if srv=='A' else 1-hB
            ns='B' if srv=='A' else 'A'
            for a,b,p in [(ga+1,gb,pr*pAG),(ga,gb+1,pr*(1-pAG))]:
                if p<=0: continue
                term=(a==6 and b<=4) or (b==6 and a<=4) or (a==7 and b==5) or (b==7 and a==5)
                if term: out[(a,b,ns)]+=p
                else: nxt[(a,b,ns)]+=p; any_=True
        active=nxt
        if not any_: break
    z=sum(out.values())
    return {k:v/z for k,v in out.items()}
def bo3_score(spwA, spwB, sf='AUTO'):
    starts=[('A',.5),('B',.5)] if sf=='AUTO' else [(sf,1)]
    states=collections.defaultdict(float)
    for s,w in starts: states[(0,0,s)] += w
    score=collections.defaultdict(float)
    for setNo in range(3):
        nxt=collections.defaultdict(float)
        for (sa,sb,srv),pr in states.items():
            sd=set_dist(round(spwA,8),round(spwB,8),srv)
            for (xA,xB,ns),ps in sd.items():
                nsa=sa+(xA>xB); nsb=sb+(xB>xA); p=pr*ps
                if nsa==2 or nsb==2:
                    score[(nsa,nsb)]+=p
                else:
                    nxt[(nsa,nsb,ns)]+=p
        states=nxt
    z=sum(score.values())
    score={k:v/z for k,v in score.items()}
    p3=score.get((2,1),0)+score.get((1,2),0)
    return p3, score
mx=(0,None)
for a in np.linspace(.45,.75,31):
    for b in np.linspace(.45,.75,31):
        p3,sc=bo3_score(float(a),float(b))
        if p3>mx[0]: mx=(p3,(a,b,sc))
mx[:2]


(0.5000000000000001,
 (np.float64(0.6),
  np.float64(0.6),
  {(2, 0): 0.24999999999999956,
   (0, 2): 0.25000000000000044,
   (2, 1): 0.2499999999999998,
   (1, 2): 0.2500000000000003}))