Difference in Spatial Convolution: Numpy vs Matlab

conv.m

a = [ 0  3  1 -4]
b = [-1 -1 -1  3]
c = cconv(a, b, 4) %  [12     4   -16     0]
l = conv(a, b, 'same') % [ -4     0    12     7]
f = conv(a, b) % [0    -3    -4     0    12     7   -12]

conv.py

import numpy as np
import scipy as sp
import scipy.signal

def spatial_full(img, kernel):
    return sp.signal.convolve(img, kernel, mode='full', method="direct")

def spatial_linear(img, kernel):
    return sp.signal.convolve(img, kernel, mode='same', method="direct")

def spatial_circ(img, kernel):
    return sp.ndimage.convolve1d(img, kernel, mode='wrap')

a = np.array([ 0,  3,  1, -4])
b = np.array([-1, -1, -1,  3])

c = spatial_circ(a, b) # array([-16,   0,  12,   4])
l = spatial_linear(a, b) # array([-3, -4,  0, 12])
f = spatial_full(a, b) # array([  0,  -3,  -4,   0,  12,   7, -12])