Bessel function with octave(answer Bard Skaflstad)

[john]

Hi,

Thank you very much for your help.I tried this

function y=besintj0(x)
global x
y=1/pi*quad(@bintegra,0,pi); thats line 18 of besintj0
endfunction


function y=bintegra(q)
global x
y=(cos(x.*sin(q));thats line 4 of bintegra(here the error product
nonconformant.
endfunction

when I run this application I get the following error:


octave.exe:2> clear all
octave.exe:3> besseljm
Approximate the Bessel function via Taylor''s series
expansion, which fails for x far away from the point
of expansion around x=0.  This program is accurate to
about 5 significant figures for 0<x<10.

Enter x: 3

Taylor''s series expansion gives:  -0.26005
error: product: nonconformant arguments (op1 is 0x0, op2 is 1x13)
error: evaluating argument list element number 1
error: evaluating argument list element number 1
error: called from:
error:   C:\Program Files\3.2.4_gcc-4.4.0\bin\mfiles\bintegra.m at line 4,
column 2
error:   C:\Program
Files\3.2.4_gcc-4.4.0\share\octave\3.2.4\m\general\quadl.m at line 93,
column 5
error:   C:\Program Files\3.2.4_gcc-4.4.0\bin\mfiles\besintj0.m at line 18,
column 3
error: evaluating argument list element number 1
error: evaluating argument list element number 1
error: evaluating argument list element number 1
error: evaluating argument list element number 1
error:   C:\Program Files\3.2.4_gcc-4.4.0\bin\mfiles\besseljm.m at line 23,
column 4
octave.exe:3>

the error about the product is like multiplication of matrices.Is it right??

Next time I avoid the "global" statement but it is just for curiousity

Sincerely

Gilbert (John)
Belgium

address@hidden



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