Bug in Convolve, version 7
- To: mathgroup at smc.vnet.net
- Subject: [mg98354] Bug in Convolve, version 7
- From: dh <dh at metrohm.com>
- Date: Wed, 8 Apr 2009 02:48:23 -0400 (EDT)
Hello,
convolution is commutative, f*g == g*f.
now consider the 2 calulations, where we simply exchange the first 2
arguments of Convolve:
f = UnitBox;
Convolve[f[x1], f[x1], x1, x2]
Convolve[%, f[x2], x2, x3]
Convolve[%, f[x3], x3, x4]
Plot[%, {x4, -2, 2}]
f = UnitBox;
Convolve[f[x1], f[x1], x1, x2]
Convolve[f[x2], %, x2, x3]
Convolve[f[x3], %, x3, x4]
Plot[%, {x4, -2, 2}]
wheras the first calculation is correct, the second is obviously wrong.
Daniel
P.S. i tried this with version 7.0.1 and Windows