Help me on function definition

[aeneng]

Hello everyone,

I am just starting to use python in numerical cacluation. 
I need you to help me to see what's wrong with the following piece of 
codes, which computes the cross product of two vectors and returns 
the result. u and v are two 3x1 matrix.

when I import the function, error message show like this
>>> import cross
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "cross.py", line 8
    ppp2=u[2]*v[0]-u[0]*v[2]
    ^
SyntaxError: invalid syntax

WHAT IS WRONG WITH MY CODE?

I appreciate your help.

##here is the function definition.
##cross.py##
def cross(u,v)
    """input two vectors u and v in 3-D space,     
       output a cross product of vector w, in column or in row 
accordingly."""
    ppp1,ppp2,ppp3=0.0,0.0,0.0
    ppp1=u[1]*v[2]-u[2]*v[1]
    ppp2=u[2]*v[0]-u[0]*v[2]
    ppp3=u[0]*v[1]-u[1]*v[0]
    # store the result of the cross product in u
    u[0]=ppp1
    u[1]=ppp2
    u[2]=ppp3
    return u #return the cross product of vector u x v. 
if __name__=="__main__":
	from cvxopt.base import matrix
	u=matrix([1.0,0.0,0.0],(3,1))
	v=matrix([0.0,1.0,0.0],(3,1))
	print cross(u,v)
	print "file name is %s" %__name__