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std::log10(std::complex)

來自 cppreference.com
< cpp‎ | 數值‎ | 複數
 
 
 
 
定義於標頭檔案 <complex>
template< class T >
std::complex<T> log10( const std::complex<T>& z );

計算複數值 z 的複數常用(以 10 為底)對數,其分支切割沿負實軸。

此函式的行為等同於 std::log(z) / std::log(T(10))

目錄

[編輯] 引數

z - 複數型別的值

[編輯] 返回值

複數 z 的常用複對數。

[編輯] 示例

#include <cmath>
#include <complex>
#include <iostream>
 
int main()
{
    std::complex<double> z(0.0, 1.0); // r = 0, θ = pi / 2
    std::cout << "2 * log10" << z << " = " << 2.0 * std::log10(z) << '\n';
 
    std::complex<double> z2(sqrt(2.0) / 2, sqrt(2.0) / 2); // r = 1, θ = pi / 4
    std::cout << "4 * log10" << z2 << " = " << 4.0 * std::log10(z2) << '\n';
 
    std::complex<double> z3(-100.0, 0.0); // r = 100, θ = pi
    std::cout << "log10" << z3 << " = " << std::log10(z3) << '\n';
    std::complex<double> z4(-100.0, -0.0); // the other side of the cut
    std::cout << "log10" << z4 << " = " << std::log10(z4) << " "
                 "(the other side of the cut)\n"
                 "(note: pi / log(10) = " << std::acos(-1.0) / std::log(10.0) << ")\n";
}

可能的輸出

2 * log10(0,1) = (0,1.36438)
4 * log10(0.707107,0.707107) = (0,1.36438)
log10(-100,0) = (2,1.36438)
log10(-100,-0) = (2,-1.36438) (the other side of the cut)
(note: pi / log(10) = 1.36438)

[編輯] 參閱

具有沿負實軸分支割線的複數自然對數
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計算常用(以 10 為底)對數 (log10(x))
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將函式 std::log10 應用於 valarray 的每個元素
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