code-generation-printing

# SymPy 代码生成与打印 本文档涵盖了 SymPy 生成多种语言可执行代码、将表达式转换为不同输出格式以及自定义打印行为的功能。 ## 代码生成 ### 转换为 NumPy 函数 python from sympy import symbols, sin, cos, lambdify import numpy as np x, y = symbols('x y') expr = sin(x) + cos(y) # 创建 NumPy 函数 f = lambdify((x, y), expr, 'numpy') # 与 NumPy 数组配合使用 x_vals = np.linspace(0, 2*np.pi, 100) y_vals = np.linspace(0, 2*np.pi, 100) result = f(x_vals, y_vals) ### Lambdify 选项 python from sympy import lambdify, exp, sqrt # 不同的后端 f_numpy = lambdify(x, expr, 'numpy') # NumPy f_scipy = lambdify(x, expr, 'scipy') # SciPy f_mpmath = lambdify(x, expr, 'mpmath') # mpmath (任意精度) f_math = lambdify(x, expr, 'math') # Python math 模块 # 自定义函数映射 custom_funcs = {'sin': lambda x: x} # 将 sin 替换为恒等函数 f = lambdify(x, sin(x), modules=[custom_funcs, 'numpy']) # 多个表达式 exprs = [x**2, x**3, x**4] f = lambdify(x, exprs, 'numpy') # 返回结果元组 ### 生成 C/C++ 代码 python from sympy.utilities.codegen import codegen from sympy import symbols x, y = symbols('x y') expr = x**2 + y**2 # 生成 C 代码 [(c_name, c_code), (h_name, h_header)] = codegen( ('distance_squared', expr), 'C', header=False, empty=False ) print(c_code) # 输出有效的 C 函数 ### 生成 Fortran 代码 python from sympy.utilities.codegen import codegen [(f_name, f_code), (h_name, h_interface)] = codegen( ('my_function', expr), 'F95', # Fortran 95 header=False ) print(f_code) ### 高级代码生成 python from sympy.utilities.codegen import CCodeGen, make_routine from sympy import MatrixSymbol, Matrix # 矩阵运算 A = MatrixSymbol('A', 3, 3) expr = A + A.T # 创建例程 routine = make_routine('matrix_sum', expr) # 生成代码 gen = CCodeGen() code = gen.write([routine], prefix='my_module') ### 代码打印器 python from sympy.printing.c import C99CodePrinter, C89CodePrinter from sympy.printing.fortran import FCodePrinter from sympy.printing.cxx import CXX11CodePrinter # C 代码 c_printer = C99CodePrinter() c_code = c_printer.doprint(expr) # Fortran 代码 f_printer = FCodePrinter() f_code = f_printer.doprint(expr) # C++ 代码 cxx_printer = CXX11CodePrinter() cxx_code = cxx_prin