On Thu, Jul 28, 2016 at 7:54 AM, Ether Jones <address@hidden> wrote:
I = dblquad(@(r,q)real(r.*sqrt(r.^2+1-2*cos(2*pi*q))),0,1,0,1)
I = dblquad(@(r,q)imag(r.*sqrt(r.^2+1-2*cos(2*pi*q))),0,1,0,1)
Thank you.
This works:
octave-3.6.4.exe:3> I = dblquad(@(r,q)abs(
r.*sqrt(r.^2+1-2*cos(2*pi*q))),0,1,0,1)
I = 0.586626703381746
... but this doesn't:
octave-3.6.4.exe:4> I =
dblquad(@(r,q)r.*sqrt(r.^2+1-2*cos(2*pi*q)),0,1,0,1)
error: quadcc: integrand F must return a single, real-valued vector
error: called from:
error: K:\OctaveVS\share\octave\3.6.4\m\general\dblquad.m at line 72,
column 10
error: at line -1, column -1
error: quadcc: integrand F must return a single, real-valued vector
error: K:\OctaveVS\share\octave\3.6.4\m\general\dblquad.m at line 65,
column 5
Why is the abs() necessary?
Your range of values for r and p start at zero.
if you put 0 and 0 in your eq. you get
sqrt(0^2+1-2*1)
sqrt(-1) this is imaginary
instead of abs you could try
Look at the plot of the surfase when you ask for the real part.
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