trigamma

auto eve::trigamma = functor<trigamma_t>

inlineconstexpr

Header file

#include <eve/module/special.hpp>

Callable Signatures

namespace eve
{
   // Regular overload
   constexpr auto trigamma(floating_value auto x)                          noexcept; // 1
 
   // Lanes masking
   constexpr auto trigamma[conditional_expr auto c](floating_value auto x) noexcept; // 2
   constexpr auto trigamma[logical_value auto m](floating_value auto x)    noexcept; // 2
}

Parameters

• x: floating_value.
• c: Conditional expression masking the operation.
• m: Logical value masking the operation.

Return value

1. The value of the Trigamma function: \(\psi(x) = \frac{\Gamma'(x)}{\Gamma(x)}\) is returned.
2. The operation is performed conditionally.

External references

• DLMF: Gamma and Psi Functions
• Wolfram MathWorld: Trigamma Function

Example

// revision 0
#include <eve/module/special.hpp>
#include <iostream>
#include <iomanip>
 
int main()
{
  eve::wide wf = {0.5, 1.0, 1.5, 2.0, 3.0, 10.0, 0.25, 100.0};
 
  std::cout << std::setprecision(15);
  std::cout << "<- wf              = " << wf << "\n";
  std::cout << "-> trigamma(wf)    = " << eve::trigamma(wf) << "\n";
  std::cout << "-> trigamma[wf > 1.0](wf) = " << eve::trigamma[wf > 1.0](wf) << "\n";
}