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Tutorial: Move step 10 to step 4

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Shifts steps 4-9 to 5-10.
This commit is contained in:
Markus Ferrell
2022-07-20 13:24:40 -04:00
parent ad20e7b2ae
commit ccba87b05b
42 changed files with 224 additions and 313 deletions
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48
Help/guide/tutorial/Step8/MathFunctions/CMakeLists.txt
View File

@@ -1,29 +1,37 @@
# first we add the executable that generates the table
add_executable(MakeTable MakeTable.cxx)
# 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
)
# add the main library
add_library(MathFunctions
mysqrt.cxx
${CMAKE_CURRENT_BINARY_DIR}/Table.h
)
add_library(MathFunctions mysqrt.cxx)
# state that anybody linking to us needs to include the current source dir
# to find MathFunctions.h, while we don't.
# state that we depend on Tutorial_BINARY_DIR but consumers don't, as the
# TutorialConfig.h include is an implementation detail
# state that we depend on our binary dir to find Table.h
target_include_directories(MathFunctions
INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
PRIVATE ${CMAKE_CURRENT_BINARY_DIR}
)
target_link_libraries(MathFunctions tutorial_compiler_flags)
# does this system provide the log and exp functions?
include(CheckCXXSourceCompiles)
check_cxx_source_compiles("
#include <cmath>
int main() {
std::log(1.0);
return 0;
}
" HAVE_LOG)
check_cxx_source_compiles("
#include <cmath>
int main() {
std::exp(1.0);
return 0;
}
" HAVE_EXP)
# add compile definitions
if(HAVE_LOG AND HAVE_EXP)
target_compile_definitions(MathFunctions
PRIVATE "HAVE_LOG" "HAVE_EXP")
endif()
# install rules
install(TARGETS MathFunctions DESTINATION lib)
set(installable_libs MathFunctions tutorial_compiler_flags)
install(TARGETS ${installable_libs} DESTINATION lib)
install(FILES MathFunctions.h DESTINATION include)

17
Help/guide/tutorial/Step8/MathFunctions/mysqrt.cxx
View File

@@ -1,10 +1,8 @@
#include <cmath>
#include <iostream>
#include "MathFunctions.h"
// include the generated table
#include "Table.h"
// a hack square root calculation using simple operations
double mysqrt(double x)
{
@@ -12,12 +10,13 @@ double mysqrt(double x)
return 0;
}
// use the table to help find an initial value
// if we have both log and exp then use them
#if defined(HAVE_LOG) && defined(HAVE_EXP)
double result = std::exp(std::log(x) * 0.5);
std::cout << "Computing sqrt of " << x << " to be " << result
<< " using log and exp" << std::endl;
#else
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) {
@@ -28,6 +27,6 @@ double mysqrt(double x)
result = result + 0.5 * delta / result;
std::cout << "Computing sqrt of " << x << " to be " << result << std::endl;
}
#endif
return result;
}