I have no idea whether this is a problem with boost or Eigen, but putting
boost::multiprecision into Eigen Array/Matrix worked in older versions of
Eigen from circa 2017, but no longer does. For instance this example (
https://www.boost.org/doc/libs/1_75_0/libs/multiprecision/doc/html/boost_multiprecision/tut/eigen.html
; copied below) used to work, but now when I compile with master, I get
complaints about the NumTraits. I'm at
commit fdf2ee62c5174441076fb64c9737d89bbe102759. I tried to look into this
a bit, but template-fu needs work.
On Visual Studio 2019:
Build started...
1>------ Build started: Project: boosteigen, Configuration: Release x64
------
1>boosteigentest.cpp
1>C:\Users\ihb\PapersInProgress\Working\03a.
UlrichCubicSuperAncillary\code\bld\_deps\boost-src\boost/multiprecision/eigen.hpp(147,23):
error C2977: 'Eigen::internal::conj_impl': too many template arguments
1>C:\Users\ihb\PapersInProgress\Working\03a.
UlrichCubicSuperAncillary\code\bld\_deps\boost-src\boost/multiprecision/eigen.hpp(147):
message : see declaration of 'Eigen::internal::conj_impl'
1>C:\Users\ihb\PapersInProgress\Working\03a.
UlrichCubicSuperAncillary\code\bld\_deps\boost-src\boost/multiprecision/eigen.hpp(164,8):
error C2977: 'Eigen::internal::conj_impl': too many template arguments
1>C:\Users\ihb\PapersInProgress\Working\03a.
UlrichCubicSuperAncillary\code\bld\_deps\boost-src\boost/multiprecision/eigen.hpp(157):
message : see declaration of 'Eigen::internal::conj_impl'
And on gcc 9.3.0:
[100%] Building CXX object CMakeFiles/boosteigen.dir/boosteigentest.cpp.o
In file included from /input/boosteigentest.cpp:3:
/bld/_deps/boost-src/boost/multiprecision/eigen.hpp:147:14: error:
redeclared with 2 template parameters
147 | struct conj_impl;
| ^~~~~~~~~
In file included from
/input/externals/ChebTools/externals/Eigen/Eigen/Core:164,
from
/bld/_deps/boost-src/boost/multiprecision/eigen.hpp:10,
from /input/boosteigentest.cpp:3:
/input/externals/ChebTools/externals/Eigen/Eigen/src/Core/MathFunctions.h:263:34:
note: previous declaration 'template<class Scalar> struct
Eigen::internal::conj_impl' used 1 template parameter
263 | template<typename Scalar> struct conj_impl :
conj_default_impl<Scalar> {};
| ^~~~~~~~~
In file included from /input/boosteigentest.cpp:3:
/bld/_deps/boost-src/boost/multiprecision/eigen.hpp:157:100: error: wrong
number of template arguments (2, should be 1)
157 | struct
conj_impl<boost::multiprecision::detail::expression<tag, Arg1, Arg2, Arg3,
Arg4>, true>
|
^
In file included from
/input/externals/ChebTools/externals/Eigen/Eigen/Core:164,
from
/bld/_deps/boost-src/boost/multiprecision/eigen.hpp:10,
from /input/boosteigentest.cpp:3:
/input/externals/ChebTools/externals/Eigen/Eigen/src/Core/MathFunctions.h:263:34:
note: provided for 'template<class Scalar> struct
Eigen::internal::conj_impl'
263 | template<typename Scalar> struct conj_impl :
conj_default_impl<Scalar> {};
| ^~~~~~~~~
Example:
#include <iostream>#include <boost/multiprecision/cpp_complex.hpp>#include <boost/multiprecision/eigen.hpp>#include <Eigen/Dense>
int main(){
using namespace Eigen;
typedef boost::multiprecision::cpp_complex_quad complex_type;
//
// We want to solve Ax = b for x,
// define A and b first:
//
Matrix<complex_type, 2, 2> A, b;
A << complex_type(2, 3), complex_type(-1, -2), complex_type(-1, -4), complex_type(3, 6);
b << 1, 2, 3, 1;
std::cout << "Here is the matrix A:\n" << A << std::endl;
std::cout << "Here is the right hand side b:\n" << b << std::endl;
//
// Solve for x:
//
Matrix<complex_type, 2, 2> x = A.fullPivHouseholderQr().solve(b);
std::cout << "The solution is:\n" << x << std::endl;
//
// Compute the error in the solution by using the norms of Ax - b and b:
//
complex_type::value_type relative_error = (A*x - b).norm() / b.norm();
std::cout << "The relative error is: " << relative_error << std::endl;
return 0;}