20       <panic_description>&lt;p&gt;This panic is raised by &lt;code&gt;operator+=&lt;/code&gt;, &lt;code&gt;operator-=&lt;/code&gt; and &lt;code&gt;operator*=&lt;/code&gt; of a &lt;code class="ApiItem"&gt;TRealX&lt;/code&gt;, when the the operands are invalid.&lt;/p&gt;&lt;p&gt;For &lt;code&gt;operator+=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;p&gt;the target operand is not a number,&lt;/p&gt; &lt;p&gt;the source operand is not a number,&lt;/p&gt; &lt;p&gt;the target and the source operands are infinite and have different signs.&lt;/p&gt; &lt;p&gt; For &lt;code&gt;operator-=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;p&gt;the target operand is not a number, &lt;/p&gt; &lt;p&gt;the source operand is not a number,&lt;/p&gt; &lt;p&gt;the target and the source operands are infinite and have different signs&lt;/p&gt; &lt;p&gt;For &lt;code&gt;operator*=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;p&gt;the target operand is not a number, &lt;/p&gt; &lt;p&gt;the source operand is not a number, &lt;/p&gt; &lt;p&gt;the target operand is infinite and the source operand is zero &lt;/p&gt; &lt;p&gt;the target operand is zero and the source operand is infinite.&lt;/p&gt; &lt;p&gt;For &lt;code&gt;operator/=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;p&gt;the target operand is not a number,&lt;/p&gt; &lt;p&gt;the source operand is not a number,&lt;/p&gt; &lt;p&gt;the target operand and the source operand are both infinite,&lt;/p&gt; &lt;p&gt;the target operand and the source operand are both zero.&lt;/p&gt;</panic_description>

    20       <panic_description>&lt;p&gt;This panic is raised by &lt;code&gt;operator+=&lt;/code&gt;, &lt;code&gt;operator-=&lt;/code&gt; and &lt;code&gt;operator*=&lt;/code&gt; of a &lt;code class="ApiItem" &gt;TRealX&lt;/code&gt;, when the the operands are invalid.&lt;/p&gt; &lt;p&gt;For &lt;code&gt;operator+=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;ul&gt; &lt;li&gt; &lt;p&gt; the target operand is not a number &lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the source operand is not a number&lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the target and the source operands are infinite and have different signs.&lt;/p&gt; &lt;/li&gt; &lt;/ul&gt; &lt;p&gt; For &lt;code&gt;operator-=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;ul&gt; &lt;li&gt; &lt;p&gt;the target operand is not a number &lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the source operand is not a number&lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the target and the source operands are infinite and have different signs&lt;/p&gt; &lt;/li&gt; &lt;/ul&gt; &lt;p&gt;For &lt;code&gt;operator*=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;ul&gt; &lt;li&gt; &lt;p&gt;the target operand is not a number &lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the source operand is not a number &lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the target operand is infinite and the source operand is zero &lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the target operand is zero and the source operand is infinite.&lt;/p&gt; &lt;/li&gt; &lt;/ul&gt; &lt;p&gt;For &lt;code&gt;operator/=&lt;/code&gt;, the panic is raised if one of these conditions applies:&lt;/p&gt; &lt;ul&gt; &lt;li&gt; &lt;p&gt;the target operand is not a number&lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the source operand is not a number&lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the target operand and the source operand are both infinite&lt;/p&gt; &lt;/li&gt; &lt;li&gt; &lt;p&gt;the target operand and the source operand are both zero.&lt;/p&gt; &lt;/li&gt; &lt;/ul&gt;</panic_description>