replace ThirdParty/Core/Faddeeva by external Cerf

this requires some ad-hoc code to work with both the C and the CPP
version of libcerf.

CMakeLists.txt

@@ -20,6 +20,7 @@ project(BornAgain
     ) # LANGUAGES CXX)
      # TODO modernize FindCerf to get rid of AssertLibraryFunction to restore restriction to CXX
 
+set(CMAKE_C_STANDARD 11)
 set(CMAKE_CXX_STANDARD 14)
 
 include(CTest) # equivalent to "enable_testing() ???

Core/CMakeLists.txt

@@ -12,7 +12,11 @@ readability-*,-readability-braces-around-statements,modernize-*")
 endif()
 
 # --- source and include files ---------
-file(GLOB source_files "*/*.cpp")
+file(GLOB source_files "*/*.cpp" )
+if(NOT Cerf_IS_CPP)
+    file(GLOB s2 "*/*.c" )
+    list(APPEND source_files ${s2})
+endif()
 file(GLOB include_files "*/*.h")
 
 if(BORNAGAIN_PYTHON)
@@ -117,6 +121,9 @@ endif()
 
 
 # --- making library ---------
+if(${Cerf_IS_CPP})
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DCERF_AS_CPP=ON")
+endif()
 add_library(${library_name} SHARED ${source_files})
 
 set_target_properties(${library_name} PROPERTIES PREFIX ${libprefix} SUFFIX ${libsuffix})
@@ -146,9 +153,9 @@ target_include_directories(${library_name}
     PUBLIC ${CMAKE_SOURCE_DIR} ${Boost_INCLUDE_DIRS} ${FFTW3_INCLUDE_DIR} ${GSL_INCLUDE_DIR}
     ${tspectrum_INCLUDE_DIR}
     SYSTEM PUBLIC ${EIGEN3_INCLUDE_DIR}
-    PRIVATE ${Faddeeva_INCLUDE_DIR})
+    PRIVATE ${Cerf_INCLUDE_DIR})
 target_link_libraries(${library_name} ${Boost_LIBRARIES} ${FFTW3_LIBRARIES} ${GSL_LIBRARIES}
-    ${Faddeeva_LIBRARY} ${tspectrum_LIBRARY})
+    ${tspectrum_LIBRARY} ${Cerf_LIBRARIES})
 
 if(BORNAGAIN_MPI)
     add_definitions(-DBORNAGAIN_MPI)

Core/Computation/RoughMultiLayerComputation.cpp

@@ -23,7 +23,20 @@
 #include "Core/Multilayer/LayerRoughness.h"
 #include "Core/Multilayer/MultiLayer.h"
 #include "Core/SimulationElement/SimulationElement.h"
-#include "Faddeeva.hh"
+
+#ifdef CERF_AS_CPP
+#include <cerf.h>
+#else
+#include "cerfwrap.h"
+std::complex<double> cerfcx(std::complex<double> z) {
+    const double zx = z.real();
+    const double zy = z.imag();
+    double vx;
+    double vy;
+    wrap_cerfcx(zx, zy, &vx, &vy);
+    return {vx, vy};
+}
+#endif
 
 // Diffuse scattering from rough interfaces is modelled after
 // Phys. Rev. B, vol. 51 (4), p. 2311 (1995)
@@ -32,11 +45,11 @@ namespace
 {
 complex_t h_plus(complex_t z)
 {
-    return 0.5 * Faddeeva::erfcx(-mul_I(z) / std::sqrt(2.0));
+    return 0.5 * cerfcx(-mul_I(z) / std::sqrt(2.0));
 }
 complex_t h_min(complex_t z)
 {
-    return 0.5 * Faddeeva::erfcx(mul_I(z) / std::sqrt(2.0));
+    return 0.5 * cerfcx(mul_I(z) / std::sqrt(2.0));
 }
 } // namespace
 

Core/Computation/cerfwrap.c

+#include "cerfwrap.h"
+#include <cerf.h>
+
+#  if !defined(CMPLX) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7\
+)) && !(defined(__ICC) || defined(__INTEL_COMPILER))
+#    define CMPLX(a,b) __builtin_complex((double) (a), (double) (b))
+#  endif
+
+#  ifdef CMPLX // C11
+#    define C(a,b) CMPLX(a,b)
+#  else
+#    define C(a,b) ((a) + I*(b))
+#  endif
+
+void wrap_cerfcx(double zx, double zy, double* vx, double* vy)
+{
+    const double _Complex arg = C(zx,zy);
+    const double _Complex val = cerfcx(arg);
+    *vx = creal(val);
+    *vy = cimag(val);
+}

Core/Computation/cerfwrap.h

+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void wrap_cerfcx(double zx, double zy, double* vx, double* vy);
+
+#ifdef __cplusplus
+}
+#endif

ThirdParty/Core/CMakeLists.txt

-add_subdirectory(Faddeeva)
 add_subdirectory(tspectrum)

ThirdParty/Core/Faddeeva/CMakeLists.txt

-############################################################################
-# CMakeLists.txt file for building libFaddeeva package
-############################################################################
-set(library_name Faddeeva)
-
-# --- source and include files ---------
-set(include_dirs
-    ${CMAKE_CURRENT_SOURCE_DIR}
-)
-include_directories(${include_dirs})
-
-file(GLOB source_files "*.cc")
-
-file(GLOB include_files "*.hh")
-
-# --- making library ------------
-add_library(
-    ${library_name}
-    STATIC
-    ${source_files} ${include_files}
-)
-set(${library_name}_INCLUDE_DIR ${include_dirs} CACHE INTERNAL "")
-set(${library_name}_LIBRARY ${library_name} CACHE INTERNAL "")

ThirdParty/Core/Faddeeva/Faddeeva.hh

-/* Copyright (c) 2012 Massachusetts Institute of Technology
- * 
- * Permission is hereby granted, free of charge, to any person obtaining
- * a copy of this software and associated documentation files (the
- * "Software"), to deal in the Software without restriction, including
- * without limitation the rights to use, copy, modify, merge, publish,
- * distribute, sublicense, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- * 
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- * 
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
- * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
- * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 
- */
-
-/* Available at: http://ab-initio.mit.edu/Faddeeva
-
-   Header file for Faddeeva.cc; see that file for more information. */
-
-#ifndef FADDEEVA_HH
-#define FADDEEVA_HH 1
-
-#include <complex>
-
-namespace Faddeeva {
-
-// compute w(z) = exp(-z^2) erfc(-iz) [ Faddeeva / scaled complex error func ]
-extern std::complex<double> w(std::complex<double> z,double relerr=0);
-extern double w_im(double x); // special-case code for Im[w(x)] of real x
-
-// Various functions that we can compute with the help of w(z)
-
-// compute erfcx(z) = exp(z^2) erfc(z)
-extern std::complex<double> erfcx(std::complex<double> z, double relerr=0);
-extern double erfcx(double x); // special case for real x
-
-// compute erf(z), the error function of complex arguments
-extern std::complex<double> erf(std::complex<double> z, double relerr=0);
-extern double erf(double x); // special case for real x
-
-// compute erfi(z) = -i erf(iz), the imaginary error function
-extern std::complex<double> erfi(std::complex<double> z, double relerr=0);
-extern double erfi(double x); // special case for real x
-
-// compute erfc(z) = 1 - erf(z), the complementary error function
-extern std::complex<double> erfc(std::complex<double> z, double relerr=0);
-extern double erfc(double x); // special case for real x
-
-// compute Dawson(z) = sqrt(pi)/2  *  exp(-z^2) * erfi(z)
-extern std::complex<double> Dawson(std::complex<double> z, double relerr=0);
-extern double Dawson(double x); // special case for real x
-
-} // namespace Faddeeva
-
-#endif // FADDEEVA_HH

cmake/extensions/FindCerf.cmake

@@ -21,7 +21,11 @@ find_library(Cerf_LIBRARIES NAMES cerf)
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(Cerf DEFAULT_MSG Cerf_LIBRARIES Cerf_INCLUDE_DIR)
 
-if(NOT Cerf_FOUND)
+if(Cerf_FOUND)
+   message(STATUS "Found libcerf, version ${Cerf_VERSION}, lib=${Cerf_LIBRARIES},\
+ include_dir=${Cerf_INCLUDE_DIR}.")
+   set(Cerf_IS_CPP OFF)
+else()
     unset(Cerf_FOUND)
     unset(Cerf_LIBRARIES)
     find_library(Cerf_LIBRARIES NAMES cerfcpp)
@@ -35,11 +39,9 @@ if(NOT Cerf_FOUND)
         message(STATUS "Found neither libcerf nor libcerfcpp")
         return()
     endif()
-    message(STATUS "Found libcerfcpp")
+    message(STATUS "Found libcerfcpp, version ${Cerf_VERSION}, lib=${Cerf_LIBRARIES},\
+ include_dir=${Cerf_INCLUDE_DIR}.")
     set(Cerf_IS_CPP ON)
-else()
-   message(STATUS "Found libcerf")
-   set(Cerf_IS_CPP OFF)
 endif()
 
 mark_as_advanced(Cerf_INCLUDE_DIR Cerf_LIBRARIES)

cmake/modules/SearchInstalledSoftware.cmake

@@ -5,7 +5,7 @@ find_package(FFTW3 REQUIRED)
 find_package(GSL REQUIRED)
 
 find_package(Cerf REQUIRED)
-
+message(STATUS "Cerf found=${Cerf_FOUND} lib=${Cerf_LIBRARIES} inc=${Cerf_INCLUDE_DIR} version={Cerf_VERSION}")
 # --- Eigen3 is a git submodule; throw an error if submodule is not initialized ---
 set(EIGEN3_INCLUDE_DIR "${CMAKE_SOURCE_DIR}/ThirdParty/Core/eigen3" CACHE INTERNAL "")
 if( NOT EXISTS "${EIGEN3_INCLUDE_DIR}/.git" )