以我发现的以前的例子为基础here https://stackoverflow.com/questions/25327845/how-to-generate-fortran-subroutine-with-sympy-codegen，我尝试找出如何生成与我需要坚持的特定形式相对应的 Fortran 代码。所需的 FORTRAN 代码将如下所示（它基于 FitzHugh-Nagumo 模型 https://en.wikipedia.org/wiki/FitzHugh%E2%80%93Nagumo_model):
SUBROUTINE FF(NE,U,PAR,F)
! ---------- --
! Define the nonlinear term
IMPLICIT NONE
INTEGER, INTENT(IN) :: NE
DOUBLE PRECISION, INTENT(IN) :: U(NE),PAR(*)
DOUBLE PRECISION, INTENT(OUT) :: F(NE)
DOUBLE PRECISION u,v,e,a1,a0
u=U(1)
v=U(2)
e=PAR(1)
a1=PAR(2)
a0=PAR(3)
F(1)= u-u**3-v
F(2)= e*(u-a1*v-a0)
END SUBROUTINE FF
我设法在 SymPy 中创建正确的表达式，但我还没有弄清楚如何使用生成所需的代码codegen。到目前为止，这是我的尝试：
from sympy import symbols,latex
from sympy.utilities.codegen import codegen
from sympy.tensor import IndexedBase, Idx
from sympy import Matrix
U, PAR = symbols('U PAR', cls=IndexedBase)
u = U[1]
v = U[2]
e = PAR[1]
a1 = PAR[2]
a0 = PAR[3]
dudt = u-u**3-v
dvdt = e*(u-a1*v-a0)
print latex(dudt)
print latex(dvdt)
F = Matrix([dudt,dvdt])
print F
result = codegen(('my_function', F), 'f95', 'my_project')
print result[0][1]
但它给了我：
IndexException:
Range is not defined for all indices in: PAR[3]
