Question

我看到其他人问过类似的东西，但无论如何我都无法弄清楚问题。我正在尝试将Matlab代码转换为Python，并且在FOR循环中的以下行之后出现问题：

dx = abs（np.diff（g_coord（num）））

下面是代码，直到该循环。任何帮助将不胜感激。我真的试图自己解决它，但没有成功。对不起，如果这是一个愚蠢的错误。 MATLAB行保留为Python注释，以防它有用。

import numpy as np
from scipy.sparse import lil_matrix 

# physical parameters
seconds_per_yr = 60*60*24*365; # number of seconds in one year
lx = 10000 ; #length of spatial domain (m)
Cp = 1e3 ; # rock heat capacity (J/kg/K)
rho = 2700 ; # rock density (kg/mˆ3)
K = 3.3 ; # bulk thermal conductivity (W/m/K)
kappa = K/(Cp*rho); # thermal diffusivity (mˆ2/s)
Tb = 0 ; # temperatures at boundaries (o C)
A = 2.6e-6 ; # heat production (W/mˆ3)
H = A/(rho*Cp); # heat source term (o K/s) % numerical parameters
dt = 1000*seconds_per_yr ; # time step (s)
ntime = 5000 ; # number of time steps
nels = 40 ; # total number of elements
nod = 2 ; # number of nodes per element
nn = nels+1 # total number of nodes
dx = lx/nels ; # element size

g_coord =  np.arange(0, lx+1, dx)#[0:dx:lx] 
bcdof = np.array([1, nn]); #[ 1 nn ] ; boundary nodes
bcval = np.array([Tb, Tb]); #[ Tb Tb ] ; # boudary values

g_num = np.zeros((nod, nels), float); #zeros(nod,nels) ;
g_num[0,:]=np.arange(1, nn); #g_num(1,:) = [1:nn-1] ;
g_num[1,:]=np.arange(2, nn+1); #g_num(2,:) = [2:nn] ;


# initialise matrices and vectors
ff = np.zeros((nn,1), float); # system load vector
b = np.zeros((nn,1), float); # system rhs vector
lhs=lil_matrix((nn, nn)) #lhs = sparse(nn,nn); system lhs matrix
rhs=lil_matrix((nn, nn)) #rhs = sparse(nn,nn); system rhs matrix
displ = np.zeros((nn,1), float); # initial temperature (o C)


#-----------------------------------------------------
# matrix assembly
#-----------------------------------------------------

# Matlab version of the loop
#-----------------------------------------------------
#for iel=1:nels # loop over all elements
#    num = g_num(:,iel) ; # retrieve equation number
#    dx = abs(diff(g_coord(num))) ; # length of element
#    MM = dx*[1/3 1/6 ; 1/6 1/3 ] ;# mass matrix
#    KM = [kappa/dx -kappa/dx ; -kappa/dx kappa/dx ]; #diffn matrix
#    F = dx*H*[1/2 ; 1/2] ; # load vector
#    lhs(num,num) = lhs(num,num) + MM/dt + KM ; # assemble lhs
#    rhs(num,num) = rhs(num,num) + MM/dt ; # assemble rhs
#    ff(num) = ff(num) + F ; # assemble load
#end # end of element loop

#Python version of the loop
#-----------------------------------------------------
for iel in range(0, nels): # loop over all elements
    num = g_num[:,iel]  # retrieve equation number
    #print(num)
    dx = abs(np.diff(g_coord[num]))  # length of element
    MM = dx*(np.array([[1/3, 1/6],[1/6, 1/3]]))  # mass matrix
    KM = np.array([[kappa/dx, -kappa/dx],[-kappa/dx, kappa/dx]]) 
    F = dx*H*(np.array([1/2, 1/2])).reshape(-1,1) # load vector
    lhs[num,num] = lhs[num,num] + MM/dt + KM # assemble lhs
    rhs[num,num] = rhs[num,num] + MM/dt # assemble rhs
    ff[num] = ff[num] + F # assemble load

Answer 1

错误似乎是因为num是float。只需：

dx = abs(np.diff(g_coord[np.int32(num)]))

然而，由于num是一个2元素数组，它会在几行之后引发另一个错误。你知道代码应该做什么，我不知道。如果您有更多问题，可以在下面发表评论，或者在第一个问题解决后编辑您的问题。

另外，我注意到你将所有;留在了行的末尾，就像在Matlab中一样。你不需要在Python中使用它。另外，我认为您在创建float矩阵时无需指定zeros，它们自然是float。

TypeError：＆＃39; numpy.ndarray＆＃39;对象不可调用

1 个答案: