Help with weave.blitz()

[monkeyboy]

Hello,

I'm a new scipy user, and I'm trying to speed up some array code with
weave. I'm running xp with gcc from cgywin, and scipy.weave.test()
returns an OK status.

I'm trying to speed up the code below. I've found a couple of examples
of weave on the web, and I think it should be straight forward, but I
keep getting the following error when calling weave.blitz(expr). It's
complaining about the variable being assigned, I've tried listing it in
the blitz call with no luck.

Any help is appreciated.

PS I've also posted to scipy.org

Thank you,

Frank


***ERROR***

Traceback (most recent call last):
 File "D:/Documents/Homework/MTMG310/Project/hw6r3VectorizeWeave.py",
line 436, in -toplevel-
   prof.runcall(main)
 File "C:\Python24\Lib\hotshot\__init__.py", line 76, in runcall
   return self._prof.runcall(func, args, kw)
 File "D:/Documents/Homework/MTMG310/Project/hw6r3VectorizeWeave.py",
line 383, in main
   findw(w,wprior,phiprior,uprior,vprior)
 File "D:/Documents/Homework/MTMG310/Project/hw6r3VectorizeWeave.py",
line 136, in findw
   weave.blitz(expr)
 File "C:\Python24\Lib\site-packages\scipy\weave\blitz_tools.py", line
35, in blitz
   if check_size and not
size_check.check_expr(expr,local_dict,global_dict):
 File "C:\Python24\Lib\site-packages\scipy\weave\size_check.py", line
51, in check_expr
   exec(expr,values)
 File "<string>", line 1
   wnext[1:grows-1,1:gcols-1] =( alpha * w[1:grows-1,1:gcols-1] + ax *
(w[1:grows-1,0:gcols-2] + w[1:grows-1,2:gcols]) +
   ^
SyntaxError: invalid syntax


***CODE***

def findw(wnext,wprior,phiprior,uprior,vprior):
   #format here is x[i,j] where i's are rows, j's columns, use flipud()
to get the
   #print out consistent with the spacial up-down directions

   #assign local names that are more
   #inline with the class notation
   w = wprior
   phi = phiprior
   u = uprior
   v = vprior


   #three of the BC are known so just set them
   #symetry plane
   wnext[0,0:gcols] = 0.0

   #upper wall
   wnext[gN,0:gcols] = 2.0/gdy**2 * (phi[gN,0:gcols] -
phi[gN-1,0:gcols])

   #inlet, off the walls
   wnext[1:grows-1,0] = 0.0


   upos = where(u>0)
   vpos = where(v>0)

   Sx = ones_like(u)
   Sx[upos] = 0.0
   xSx = 1.0 - Sx


   Sy = ones_like(v)
   Sy[vpos] = 0.0
   ySy = 1.0 - Sy

   uw = u*w
   vw = v*w

   ax = gnu*gdt/gdx**2
   ay = gnu*gdt/gdy**2
   dtdx = gdt/gdx
   dtdy = gdt/gdy

   alpha = (1.0 - 2.0*ax - 2.0*ay)


   #interior nodes
   expr = """ \
   wnext[1:grows-1,1:gcols-1] =( alpha * w[1:grows-1,1:gcols-1] + ax *
(w[1:grows-1,0:gcols-2] + w[1:grows-1,2:gcols]) +
                                 ay * (w[0:grows-2,1:gcols-1] +
w[2:grows,1:gcols-1]) -
                                 dtdx * (xSx[1:grows-1,1:gcols-1] *
(uw[1:grows-1,1:gcols-1] - uw[1:grows-1,0:gcols-2]) -
                                         Sx[1:grows-1,1:gcols-1] *
(uw[1:grows-1,2:gcols] - uw[1:grows-1,1:gcols-1])) -
                                 dtdy * (ySy[1:grows-1,1:gcols-1] *
(vw[1:grows-1,1:gcols-1] - vw[1:grows-1,0:gcols-2]) -
                                         Sy[1:grows-1,1:gcols-1] *
(vw[1:grows-1,2:gcols] - vw[1:grows-1,1:gcols-1])) )
                                         """


#weave.inline(expr,['wnext','w','Sx','xSx','Sy','ySy','uw','vw','ax','ay','dtdx','dtdy','alpha','grows','gcols'])
   #weave.inline(expr,['wnext'],compiler='gcc',verbose=2)

#weave.blitz(expr,['wnext','w','Sx','xSx','Sy','ySy','uw','vw','ax','ay','dtdx','dtdy','alpha','grows','gcols'])
   #weave.blitz(expr,size_check=1)
   #weave.inline(expr,['wnext'])
   weave.blitz(expr)



##    for j in range(1,gasizej-1):
##        for i in range(1,gasizei-1):
##
##            wnext[i,j] =( w[i,j] + gnu*gdt/gdx**2 * (w[i,j-1] -
2.0*w[i,j] + w[i,j+1]) +
##                          gnu*gdt/gdy**2 * (w[i-1,j] - 2.0*w[i,j] +
w[i+1,j]) -
##                          (1.0 - Sx[i,j]) * gdt/gdx * (uw[i,j] -
uw[i,j-1]) -
##                          Sx[i,j] * gdt/gdx * (uw[i,j+1] - uw[i,j]) -
##                          (1.0 - Sy[i,j]) * gdt/gdy * (vw[i,j] -
vw[i-1,j]) -
##                          Sy[i,j] * gdt/gdy * (vw[i+1,j] - vw[i,j]) )

##        print "***wnext****"
##        print "i: ", i, "j: ", j, "wnext[i,j]: ", wnext[i,j]

   #final BC at outlet, off walls
   wnext[1:grows-1,gM] = wnext[1:grows-1,gM-1]