Hi, I'm new to the list. I am having some difficulty finding the sum of a masked array. I'm using numarray 1.0 installed on winXP with Python 2.3.4. from numarray.ma import * Rx = ones((2500,2500)) N = make_mask_none((2500,2500)) Rx = array(Rx,mask=N) print average(Rx) ## works print sum(Rx) ## gives an error message 16 lines long, the most recent being a type error. Is there something obvious I am doing wrong here?