回答此问题可获得 20 贡献值,回答如果被采纳可获得 50 分。
<p>当我执行这段代码时,它会产生算术发散,或者不是非常接近的浮点数,当数的形式为2时会发生,n-p/q会产生一个可接受的结果,有时会产生一个非常快的发散。我读过一些关于浮点运算的文档,但我认为问题在别处,但在哪里呢?如果有人有主意,我很乐意理解这件事。。。你知道吗</p>
<p>我曾尝试在python3.4.5(32位)上执行代码,并在网上试用过复制和韦小宝网址[<a href="https://trinket.io/python3/d3f3655168]" rel="nofollow noreferrer">https://trinket.io/python3/d3f3655168]</a>的结果是相似的。你知道吗</p>
<pre class="lang-py prettyprint-override"><code>#this code illustrates arithmetical divergence with floating point numbers
# on Python 3.4 an 3.6.6
def ErrL(r):
s=1
L=[]
for k in range(10):
s=s*(r+1)-r
L.append(s)
return L
print(ErrL(2**11-2/3.0)) # this number generate a fast divergence in loop for
#[0.9999999999997726, 0.9999999995341113, 0.9999990457047261, 0.9980452851802966, -3.003907522359441, -8200.33724163292, -16799071.44994476, -34410100067.30351, -70483354973240.67, -1.4437340543685667e+17]
print(ErrL(2**12-1/3.0)) # this number generate a fast divergence in loop for
#[0.9999999999995453, 0.9999999981369001, 0.9999923674999991, 0.968732191662184, -127.09378815725313, -524756.5521508802, -2149756770.9781055, -8806836909202.637, -3.607867520470422e+16, -1.4780230608860496e+20]
print(ErrL(2**12-1/10.0)) # this number generate a fast divergence in loop for
#[0.9999999999995453, 0.9999999981369001, 0.9999923670652606, 0.9687286296662023, -127.11567712053602, -524876.117595124, -2150369062.0754633, -8809847014512.865, -3.609306223376185e+16, -1.478696666654989e+20]
print(ErrL(2**12-1/9.0)) # no problem here
#[1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0]
print(ErrL(2**12-1/11.0)) # no problem here
#[1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0]
</code></pre>
<p>我所期望的显然是一个十个一的向量!你知道吗</p>