[Python] Using Jacobian matrix in solve_ivp

I am trying to use the solve_ivp built-in function with the Jacobian matrix. I get this error message:

UserWarning: The following arguments have no effect for a chosen solver: jac. .format(", ".join("{}".format(x) for x in extraneous)))
​

I am unsure if it is a syntax error or an error in the Jacobian matrix.

Some of my code

def MyIntFun(t,y):
return DivWatFlux(y,t,wPar, sPar, RPar,dzIN, dzN)

def jacfunc(t,y):
jac = Richardsmatrix(y, t, wPar, sPar, RPar, dzIN, dzN)
return jac

mt.tic()
hwODE = spi.solve_ivp(MyIntFun, [tout[0], tout[-1]], hw0, method='RK45',
vectorized=True,rtol=1e-4, jac=jacfunc)
mt.toc()


This is the code for the Jacobian:

def Richardsmatrix(hw, t, wPar, sPar, RPar, dzIN, dzN): #the jacobian (a,b,c)

K=Kfun(hw, wPar, m)
kRes =RPar.kRobBotR

a = np.zeros(nN)
b = np.zeros(nN)
c = np.zeros(nN)


ii=np.arange(1, nN-1)

a[ii] = K[ii, 0]/(dzIN[ii, 0]*dzN[ii-1, 0]) #middle nodes
a[0] = 0 #a1l is zero and not in matrix
a[nN-1] = K[nN-1, 0] / (dzIN[nN-1, 0] * dzN[nN-2, 0])

b[ii] = -K[ii, 0] / (dzIN[ii,0] * dzN[ii-1,0])- K[ii+1,0] / (dzIN[ii,0] * dzN[ii, 0]) #middle nodes
b[0] = -K[1, 0]/(dzIN[0 , 0]*dzN[0, 0])- kRes / dzIN[0 ,0]
b[nN-1] = -K[nN-1, 0] / (dzIN[nN-1, 0] * dzN[nN-2, 0])

c[ii] = K[ii+1,0] / (dzIN[ii,0] * dzN[ii, 0]) #middle nodes
c[0] = K[1,0] / (dzIN[0, 0] * dzN[0, 0])
c[nN-1] = 0

B = np.diag(a[1:nN], -1)+ np.diag(b, 0) + np.diag(c[0:nN-1], 1)
sB = sp.sparse.csc_matrix(B)
return


My group and I are pretty new at programming, so any help is greatly appreciated!

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