E.V.E  0.1-beta

◆ logspace_add

eve::logspace_add = {}
inlineconstexpr

Callable object computing the logspace_add operation: \(\log\left(\sum_{i = 0}^n e^{x_i}\right)\).

Required header: #include <eve/function/logspace_add.hpp>

Members Functions

Member Effect
operator() the logspace_add operation
operator[] Construct a conditional version of current function object

template< floating_value T, floating_value U, floating_value ...Ts> auto operator()( T arg0, U arg1, Ts... args ) const noexcept
requires (compatible_values< T, U, Ts > && ...);
Definition: value.hpp:83

Parameters

arg0, arg1, args, ... : values.

Return value

The call logspace_add(arg0, arg1, args...) is semantically equivalent to log(exp(arg0) + exp(arg1) + exp(args)...);.

The result type is the common compatible type of the parameters.


auto operator[]( conditional_expression auto cond ) const noexcept;

Higher-order function generating a masked version of eve::logspace_add

Parameters

cond : conditional expression

Return value

A Callable object so that the expression logspace_add[cond](x, ...) is equivalent to if_else(cond,logspace_add(x, ...),x)


Supported decorators

  • eve::diff, eve::diff_1st, eve::diff_2nd, eve::diff_3rd, eve::diff_nth

    Required header: #include <eve/function/diff/logspace_add.hpp>

    The expression diff_nth< N >(logspace_add)(arg0,arg1,args...) computes the partial diff of the function relative to its Nth parameter. The returned value is 0 if N is greater that the actual number of parameters, otherwise if the parameters are \( x_1, ... x_n \) returns \( \displaystyle\frac{e^{x_N}}{e^{x_1} + ... + e^{x_n}} \)

Example

See it live on Compiler Explorer

#include <eve/function/logspace_add.hpp>
#include <eve/literals.hpp>
#include <eve/wide.hpp>
#include <iostream>
int main()
{
w_t pi = {3, 2, 3, 3}, qi = {4, 1, 1, ~0};
std::cout << "---- simd" << '\n'
<< " <- pi = " << pi << '\n'
<< " <- qi = " << qi << '\n'
<< " -> logspace_add(pi, qi) = " << eve::logspace_add(pi, qi) << '\n';
float xi = 3, yi = 4;
std::cout << "---- scalar" << '\n'
<< " xi = " << xi << '\n'
<< " yi = " << yi << '\n'
<< " -> logspace_add(xi, yi) = " << eve::logspace_add(xi, yi) << '\n';
return 0;
}
constexpr callable_pi_ pi
Callable object computing the value.
Definition: pi.hpp:54
constexpr callable_logspace_add_ logspace_add
Callable object computing the logspace_add operation: .
Definition: logspace_add.hpp:84
Wrapper for SIMD registers.
Definition: wide.hpp:65