small fix in get slab decomposition
The variable upper_slab
was referenced without initialisation. I suppose that was a typo.
This causes a crash in the code generation (maybe earlier?) if a kernel with initial slab but no final slab was created. Example:
import loopy as lp
knl = lp.make_kernel("{[i]: 0<=i<10}",
"out[i] = 2",
iname_slab_increments={'i':(1,0)})
print(lp.generate_code_v2(knl).device_code())