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FunctionParser

Repository source: FunctionParser

Description

This example shows how to substitute values and evaluate a string such as "a+b".

Other languages

See (Java)

Question

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Code

FunctionParser.cxx

#include <vtkFunctionParser.h>
#include <vtkNew.h>

int main(int, char*[])
{
  vtkNew<vtkFunctionParser> functionParser;
  functionParser->SetFunction("a+b");

  functionParser->SetScalarVariableValue("a", 2);
  functionParser->SetScalarVariableValue("b", 3);

  double result = functionParser->GetScalarResult();

  std::cout << "result: " << result << std::endl;

  return EXIT_SUCCESS;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(FunctionParser)

find_package(VTK COMPONENTS 
  CommonCore
  CommonMisc
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "FunctionParser: Unable to find the VTK build folder.")
endif()

# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(FunctionParser MACOSX_BUNDLE FunctionParser.cxx )
  target_link_libraries(FunctionParser PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS FunctionParser
  MODULES ${VTK_LIBRARIES}
)

Download and Build FunctionParser

Click here to download FunctionParser and its CMakeLists.txt file. Once the tarball FunctionParser.tar has been downloaded and extracted,

cd FunctionParser/build

If VTK is installed:

cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

make

and run it:

./FunctionParser

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.