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Organizing output in MATLAB

by Providence88
Tags: matlab, organizing, output
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Providence88
#1
Sep30-09, 04:44 PM
P: 7
So I have this code:

function ApproxSinDeriv(x,n)
h=.5;
for i = 0:n
    h;
    approx = (1/(2*h))*(sin(x+h)-sin(x-h));
    error = abs(approx-cos(x));
    h = h/2;
    A=[i,h,approx,error]
end
Basically, it's a three-point formula for approximating a derivative, where the variables n = the number of iterations, x = the input value for the sin function, i = iteration number, approx=the approximation of the derivative, and error = the difference between the actual derivative and the approximation.

I put A equal to a matrix of these values, but the output comes out in 30 clunky, individual, one-row matrices.

How would I go about putting this data in an array? That is, one nice clean matrix with 30 rows and 4 columns [i,h,approx,error]?

Thanks!

-Eric.
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trambolin
#2
Oct1-09, 04:24 AM
P: 341
function [A] = ApproxSinDeriv(x,n)
A = zeros(n+1,4)
h=.5;
for i = 0:n
    approx = (1/(2*h))*(sin(x+h)-sin(x-h));
    error = abs(approx-cos(x));
    h = h/2;
    A(i+1,:)=[i,h,approx,error];
end
Providence88
#3
Oct1-09, 12:18 PM
P: 7
Thank you! That worked great!


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