科學(xué)計(jì)算語言Julia及MWORKS實(shí)踐 課件 16-外部語言調(diào)用

四、Julia語言進(jìn)階4.4外部語言調(diào)用在數(shù)值計(jì)算領(lǐng)域，有很多用C/C++或Python編寫的高質(zhì)量且成熟的程序或工具。Julia提供了簡潔且高效的調(diào)用C/C++和Python的方法，不需要任何“膠水”代碼。調(diào)用C/C++C標(biāo)準(zhǔn)庫C++動(dòng)態(tài)鏈接庫調(diào)用PythonPython庫函數(shù)四、Julia語言進(jìn)階4.4.1C/C++函數(shù)ccall或宏@ccall調(diào)用C/C++程序#ccall函數(shù)調(diào)用ccall((function_name,library),returntype,(argtype1,...),argvalue1,...)ccall(function_name,returntype,(argtype1,...),argvalue1,...)ccall(function_pointer,returntype,(argtype1,...),argvalue1,...)#@ccall宏調(diào)用@ccalllibrary.function_name(argvalue1::argtype1,...)::returntype@ccallfunction_name(argvalue1::argtype1,...)::returntype@ccall$function_pointer(argvalue1::argtype1,...)::returntype函數(shù)名函數(shù)返回值類型輸入變臉的類型輸入變量聲明輸入變量類型函數(shù)返回值類型四、Julia語言進(jìn)階4.4.1C/C++調(diào)用自定義的C++動(dòng)態(tài)鏈接庫ArrayMaker.dll，其聲明如下#ifndef_ADD_H#define_ADD_Hextern"C"__declspec(dllexport)doubleGetSum(doublex,doubley);#endif//!_ADD_Hjulia>lib="C:\\Users…\\C\\ArrayMaker\\x64\\Debug\\ArrayMaker""C:\\Users\\...\\C\\ArrayMaker\\x64\\Debug\\ArrayMaker"julia>c=@ccalllib.GetSum(2::Cdouble,3::Cdouble)::Cdouble5.0動(dòng)態(tài)鏈接庫路徑聲明C語言的雙精度類型四、Julia語言進(jìn)階4.4.1C/C++Libdl庫加載動(dòng)態(tài)鏈接庫與釋放動(dòng)鏈接庫usingLibdl

#加載庫lib_path=joinpath(“C:\\Users\\…\\C\\ArrayMaker\\x64\\Debug\\ArrayMaker")lib=Libdl.dlopen(lib_path)

#獲取調(diào)用函數(shù)的符號GetSum=Libdl.dlsym(lib,:GetSum)

#調(diào)用函數(shù)c=@ccall$GetSum(2::Cdouble,3::Cdouble)::Cdouble

#關(guān)閉dllLibdl.dlclose(lib)注意：調(diào)用C++動(dòng)態(tài)鏈接庫時(shí)，需要dll文件、h文件和cpp文件。四、Julia語言進(jìn)階4.4.2Python用pyimport和@pyimport調(diào)用Python庫函數(shù)usingPyCallusingTyPlot

#case1math=pyimport("math")v=math.sin(pi/2)println("v=$v")#v=1.0

#case2@pyimportnumpyasnpx=np.linspace(0,2π,1000)y=np.sin(x)plot(x,y)Syslab程序運(yùn)行結(jié)果為：四、Julia語言進(jìn)階4.4.2Python調(diào)用Python文件需要三步：第一步將路徑添加到Python工作目錄；第二步導(dǎo)入Python文件；第三步調(diào)用Python接口。usingPyCall

function_set_python_path(path::AbstractString)py"""importsysdefset_path(path):ifpathnotinsys.path:sys.path.append(path)"""py"set_path"(path)end#1.將路徑添加到Python工作目錄中println(@__DIR__)_set_py