<p>如果预期结果在<code>225...240</code>范围内,则可能出现以下问题:</p>
<ul>
<li>生成<code>fun</code>时出错</li>
<li><code>d</code>中的值不正确</li>
<li>函数<code>add</code>、<code>sub</code>、<code>mul</code>和<code>safeDiv</code>应该做一些比浮点加法、减法、乘法和除法更复杂的事情。在</li>
</ul>
<p>问题中提供的输入不能给出<code>-2786.17215265</code>之外的任何内容,因为这是一个完美的数值结果。没有浮点舍入错误或溢出。下面是测试脚本的输出,其中包含详细版本的算术函数,所有浮点运算都定义良好。没有任何东西可以引起明显的舍入误差。当减去接近值时,存在一些风险操作:</p>
<pre><code>add: -10626.8589858 + 10627.794501 = 0.935515251547
</code></pre>
<p>然而,这远不是舍入误差。在</p>
<p>同样的结果可以通过C程序或数学工具(MATLAB/Octave)得到。在</p>
<hr/>
<p>屏幕截图中的不同输出是由于没有显示的局部变量的值造成的。由于<code>Out[108]</code>与<code>Out[110]</code>相同,我假设<code>ds</code>与{<cd12>}相同。局部变量用于输出<code>Out[109]</code>和<code>Out[110]</code>,因此差异在于<code>rv</code>的值,因为在<code>In[110]</code>中只有该变量被更改。如果所有其他变量的值都是固定的,那么可以看到如果<code>rv</code>等于下列值之一,则可以得到<code>Out[109]</code>(<code>230.62977145178198</code>),即<code>4.075164147</code>,<code>4.485709922</code>,<code>51.72476610</code>。下面测试脚本中的最后一行输出也说明了这一点。在</p>
<p>注意,如果<code>fun</code>被分析为<code>rv</code>的函数,它有两个极点(围绕<code>3.3</code>和{<cd26>})。所以,从技术上讲,这个函数可以给出从负无穷到正无穷的结果。在</p>
<hr/>
<blockquote>
<p>Test</p>
</blockquote>
^{pr2}$
<blockquote>
<p>Output</p>
</blockquote>
<pre><code>sub: 26.2235845341 - 0 = 26.2235845341
mul: 2708.41452689 * 3.25991727261 = 8829.20729761
add: 26.2235845341 + 8829.20729761 = 8855.43088215
add: 2708.41452689 + 3 = 2711.41452689
mul: 51.6965219541 * 2711.41452689 = 140170.700616
sub: 8855.43088215 - 140170.700616 = -131315.269734
mul: -131315.269734 * 51.6965219541 = -6788542.72473
add: 2708.41452689 + -6788542.72473 = -6785834.3102
div: 51.6965219541 / -6785834.3102 = -7.61830006318e-06
add: 0 + 3.25991727261 = 3.25991727261
sub: -7.61830006318e-06 - 3.25991727261 = -3.25992489091
sub: 2708.41452689 - 27.491618858 = 2680.92290804
div: 51.6965219541 / 26.2235845341 = 1.97137511414
sub: 1.97137511414 - 1 = 0.971375114142
div: 77.1000519162 / 51.6965219541 = 1.49139727397
sub: 4 - 54.6298636339 = -50.6298636339
div: 1.49139727397 / -50.6298636339 = -0.029456869265
add: 31.1561128065 + 51.6965219541 = 82.8526347606
add: -0.029456869265 + 82.8526347606 = 82.8231778914
div: 0.971375114142 / 82.8231778914 = 0.0117283004453
mul: 2680.92290804 * 0.0117283004453 = 31.4426693361
div: 31.4426693361 / 31.1561128065 = 1.00919744165
sub: -3.25992489091 - 1.00919744165 = -4.26912233256
add: 4 + 77.1000519162 = 81.1000519162
add: -4.26912233256 + 81.1000519162 = 76.8309295836
add: 26.2235845341 + 26.2235845341 = 52.4471690682
add: 51.6965219541 + 51.6965219541 = 103.393043908
mul: 2708.41452689 * -4 = -10833.6581076
mul: 27.491618858 * 27.491618858 = 755.789107434
div: 77.1000519162 / 31.1561128065 = 2.47463643475
div: 755.789107434 / 2.47463643475 = 305.414200171
div: 54.6298636339 / 77.1000519162 = 0.708558065477
add: 2708.41452689 + 0.708558065477 = 2709.12308496
sub: 2709.12308496 - 2708.41452689 = 0.708558065477
add: 305.414200171 + 0.708558065477 = 306.122758237
sub: 4 - 77.1000519162 = -73.1000519162
add: 306.122758237 + -73.1000519162 = 233.02270632
add: -10833.6581076 + 233.02270632 = -10600.6354013
sub: -10600.6354013 - 26.2235845341 = -10626.8589858
mul: 27.491618858 * 51.6965219541 = 1421.22107785
mul: 3.25991727261 * 54.6298636339 = 178.088836061
mul: 51.6965219541 * 178.088836061 = 9206.57342319
add: 1421.22107785 + 9206.57342319 = 10627.794501
add: -10626.8589858 + 10627.794501 = 0.935515251547
div: 51.6965219541 / 0.935515251547 = 55.2599456488
mul: 54.6298636339 * 55.2599456488 = 3018.84329521
sub: 103.393043908 - 3018.84329521 = -2915.4502513
add: 52.4471690682 + -2915.4502513 = -2863.00308224
add: 76.8309295836 + -2863.00308224 = -2786.17215265
-2786.17215265
230.629771452
</code></pre>