diff options
Diffstat (limited to 'Help/guide/tutorial/Complete/MathFunctions')
6 files changed, 164 insertions, 0 deletions
diff --git a/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt new file mode 100644 index 000000000..dfa84c941 --- /dev/null +++ b/Help/guide/tutorial/Complete/MathFunctions/CMakeLists.txt @@ -0,0 +1,63 @@ +# add the library that runs +add_library(MathFunctions MathFunctions.cxx) + +# state that anybody linking to us needs to include the current source dir +# to find MathFunctions.h, while we don't. +target_include_directories(MathFunctions + INTERFACE + $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}> + $<INSTALL_INTERFACE:include> + ) + +# should we use our own math functions +option(USE_MYMATH "Use tutorial provided math implementation" ON) +if(USE_MYMATH) + + target_compile_definitions(MathFunctions PRIVATE "USE_MYMATH") + + # first we add the executable that generates the table + add_executable(MakeTable MakeTable.cxx) + target_link_libraries(MakeTable tutorial_compiler_flags) + + # add the command to generate the source code + add_custom_command( + OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/Table.h + COMMAND MakeTable ${CMAKE_CURRENT_BINARY_DIR}/Table.h + DEPENDS MakeTable + ) + + # library that just does sqrt + add_library(SqrtLibrary STATIC + mysqrt.cxx + ${CMAKE_CURRENT_BINARY_DIR}/Table.h + ) + + # state that we depend on our binary dir to find Table.h + target_include_directories(SqrtLibrary PRIVATE + ${CMAKE_CURRENT_BINARY_DIR} + ) + + # state that SqrtLibrary need PIC when the default is shared libraries + set_target_properties(SqrtLibrary PROPERTIES + POSITION_INDEPENDENT_CODE ${BUILD_SHARED_LIBS} + ) + + target_link_libraries(SqrtLibrary PUBLIC tutorial_compiler_flags) + target_link_libraries(MathFunctions PRIVATE SqrtLibrary) +endif() + +target_link_libraries(MathFunctions PUBLIC tutorial_compiler_flags) + +# define the symbol stating we are using the declspec(dllexport) when +# building on windows +target_compile_definitions(MathFunctions PRIVATE "EXPORTING_MYMATH") + +# setup the version numbering +set_property(TARGET MathFunctions PROPERTY VERSION "1.0.0") +set_property(TARGET MathFunctions PROPERTY SOVERSION "1") + +# install rules +install(TARGETS MathFunctions tutorial_compiler_flags + DESTINATION lib + EXPORT MathFunctionsTargets) +install(FILES MathFunctions.h DESTINATION include) diff --git a/Help/guide/tutorial/Complete/MathFunctions/MakeTable.cxx b/Help/guide/tutorial/Complete/MathFunctions/MakeTable.cxx new file mode 100644 index 000000000..ee585568c --- /dev/null +++ b/Help/guide/tutorial/Complete/MathFunctions/MakeTable.cxx @@ -0,0 +1,25 @@ +// A simple program that builds a sqrt table +#include <cmath> +#include <fstream> +#include <iostream> + +int main(int argc, char* argv[]) +{ + // make sure we have enough arguments + if (argc < 2) { + return 1; + } + + std::ofstream fout(argv[1], std::ios_base::out); + const bool fileOpen = fout.is_open(); + if (fileOpen) { + fout << "double sqrtTable[] = {" << std::endl; + for (int i = 0; i < 10; ++i) { + fout << sqrt(static_cast<double>(i)) << "," << std::endl; + } + // close the table with a zero + fout << "0};" << std::endl; + fout.close(); + } + return fileOpen ? 0 : 1; // return 0 if wrote the file +} diff --git a/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.cxx b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.cxx new file mode 100644 index 000000000..014530062 --- /dev/null +++ b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.cxx @@ -0,0 +1,19 @@ + +#include "MathFunctions.h" + +#include <cmath> + +#ifdef USE_MYMATH +# include "mysqrt.h" +#endif + +namespace mathfunctions { +double sqrt(double x) +{ +#ifdef USE_MYMATH + return detail::mysqrt(x); +#else + return std::sqrt(x); +#endif +} +} diff --git a/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.h b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.h new file mode 100644 index 000000000..3fb547b4a --- /dev/null +++ b/Help/guide/tutorial/Complete/MathFunctions/MathFunctions.h @@ -0,0 +1,14 @@ + +#if defined(_WIN32) +# if defined(EXPORTING_MYMATH) +# define DECLSPEC __declspec(dllexport) +# else +# define DECLSPEC __declspec(dllimport) +# endif +#else // non windows +# define DECLSPEC +#endif + +namespace mathfunctions { +double DECLSPEC sqrt(double x); +} diff --git a/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx new file mode 100644 index 000000000..8153f18be --- /dev/null +++ b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.cxx @@ -0,0 +1,37 @@ +#include <iostream> + +#include "MathFunctions.h" + +// include the generated table +#include "Table.h" + +namespace mathfunctions { +namespace detail { +// a hack square root calculation using simple operations +double mysqrt(double x) +{ + if (x <= 0) { + return 0; + } + + // use the table to help find an initial value + double result = x; + if (x >= 1 && x < 10) { + std::cout << "Use the table to help find an initial value " << std::endl; + result = sqrtTable[static_cast<int>(x)]; + } + + // do ten iterations + for (int i = 0; i < 10; ++i) { + if (result <= 0) { + result = 0.1; + } + double delta = x - (result * result); + result = result + 0.5 * delta / result; + std::cout << "Computing sqrt of " << x << " to be " << result << std::endl; + } + + return result; +} +} +} diff --git a/Help/guide/tutorial/Complete/MathFunctions/mysqrt.h b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.h new file mode 100644 index 000000000..e1c42ef0c --- /dev/null +++ b/Help/guide/tutorial/Complete/MathFunctions/mysqrt.h @@ -0,0 +1,6 @@ + +namespace mathfunctions { +namespace detail { +double mysqrt(double x); +} +} |