std::log10(std::valarray)

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros(C++20)

Language support library

Concepts library(C++20)

Diagnostics library

Memory management library

Metaprogramming library(C++11)

General utilities library

Containers library

Iterators library

Ranges library(C++20)

Algorithms library

Strings library

Text processing library

Numerics library

Date and time library

Input/output library

Filesystem library(C++17)

Concurrency support library(C++11)

Execution control library(C++26)

Technical specifications

Symbols index

External libraries

 

Numerics library

Common mathematical functions
Mathematical special functions(C++17)
Mathematical constants(C++20)
Basic linear algebra algorithms(C++26)
Data-parallel types (SIMD)(C++26)
Floating-point environment(C++11)
Complex numbers
Numeric array (valarray)
Pseudo-random number generation
Bit manipulation(C++20)
Saturation arithmetic(C++26)
Factor operations
gcd (C++17)	lcm (C++17)
Interpolations
midpoint (C++20)	lerp (C++20)
Generic numeric operations
iota (C++11) ranges::iota (C++23) accumulate inner_product adjacent_difference    partial_sum	reduce (C++17) transform_reduce (C++17) inclusive_scan (C++17) exclusive_scan (C++17) transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)
C-style checked integer arithmetic
ckd_add (C++26) ckd_sub (C++26)	ckd_mul (C++26)

 

std::valarray

Member functions
valarray::valarray valarray::~valarray valarray::operator= valarray::operator[] valarray::swap valarray::size valarray::resize valarray::sum valarray::min valarray::max valarray::shift valarray::cshift valarray::apply	valarray::operator+valarray::operator-valarray::operator~valarray::operator! valarray::operator+=valarray::operator-=valarray::operator*=valarray::operator/=valarray::operator%=valarray::operator&=valarray::operator|=valarray::operator^=valarray::operator<<=valarray::operator>>=
Non-member functions
swap(std::valarray) (C++11) begin(std::valarray) (C++11)   end(std::valarray) (C++11) abs exp log log10 pow sqrt sin cos tan asin acos atan atan2 sinh cosh tanh	operator*operator/operator%operator+operator-operator^operator&operator|operator<<operator>>operator&&operator|| operator==operator!=operator<operator>operator<=operator>=
Helper classes
slice_array gslice_array indirect_array	slice gslice mask_array
Deduction guides(C++17)

 

Defined in header <valarray>
template<class T > valarray<T> log10(const valarray<T>& va );

For each element in va computes common (base 10) logarithm of the value of the element.

Parameters

va

-

value array to apply the operation to

Return value

Value array containing common logarithms of the values in va.

Notes

Unqualified function (log10) is used to perform the computation. If such function is not available, std::log10 is used due to argument-dependent lookup.

The function can be implemented with the return type different from std::valarray. In this case, the replacement type has the following properties:

• All const member functions of std::valarray are provided.
• std::valarray, std::slice_array, std::gslice_array, std::mask_array and std::indirect_array can be constructed from the replacement type.
• For every function taking a conststd::valarray<T>&except begin() and end()(since C++11), identical functions taking the replacement types shall be added;
• For every function taking two conststd::valarray<T>& arguments, identical functions taking every combination of conststd::valarray<T>& and replacement types shall be added.
• The return type does not add more than two levels of template nesting over the most deeply-nested argument type.

Possible implementation

template<class T> valarray<T> log10(const valarray<T>& va){ valarray<T> other = va;for(T& i : other) i = log10(i);   return other;// proxy object may be returned}

Example

Run this code

#include <cmath>#include <iomanip>#include <iostream>#include <valarray>   void show(charconst* title, conststd::valarray<float>& va){std::cout<< title <<" : "<<std::right;for(float x : va)std::cout<<std::setw(6)<< x;std::cout<<'\n';}   int main(){conststd::valarray<float> n{-2.f, -1.f, 0.f, 1.f, 2.f, 3.f, INFINITY};conststd::valarray<float> pow10{std::pow(10.f, n)};conststd::valarray<float> log10_pow10{std::log10(pow10)};   show("n ", n); show("10ⁿ ", pow10); show("lg(10ⁿ)", log10_pow10);}

Output:

n  : -2 -1 0 1 2 3 inf 10ⁿ  : 0.01 0.1 1 10 100 1000 inf lg(10ⁿ) : -2 -1 0 1 2 3 inf

See also

log(std::valarray)	applies the function std::log to each element of valarray (function template)
log10log10flog10l (C++11)(C++11)	computes common (base 10) logarithm (\({\small\log_{10}{x}}\)log10(x)) (function)
log10(std::complex)	complex common logarithm with the branch cuts along the negative real axis (function template)