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comparison scripts/signal/sinc.m @ 904:3470f1e25a79

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[project @ 1994-11-09 21:22:15 by jwe]
author jwe
date Wed, 09 Nov 1994 21:22:15 +0000
parents 4e826edfbc56
children 5cffc4b8de57
comparison
equal deleted inserted replaced
903:b3692d63cca3 904:3470f1e25a79
1 function result = sinc(x) 1 function result = sinc (x)
2 2
3 # usage: sinc(x) 3 # usage: sinc(x)
4 # 4 #
5 # Returns sin(pi*x)/(pi*x). 5 # Returns sin(pi*x)/(pi*x).
6 #
7 6
8 # We either need to set the do_fortran_indexing variable to "true" 7 # We either need to set the do_fortran_indexing variable to "true"
9 # or use reshape to convert the input matrix to a vector, so that 8 # or use reshape to convert the input matrix to a vector, so that
10 # we can use find to determine the elements of x that equal zero. 9 # we can use find to determine the elements of x that equal zero.
11 # I prefer reshaping. 10 # I prefer reshaping.
14 13
15 nels = nr*nc; 14 nels = nr*nc;
16 15
17 x = reshape(x,nels,1); 16 x = reshape(x,nels,1);
18 17
19 # Set result to all ones initially. 18 # Set result to all ones initially.
20 result = ones(nels,1); 19 result = ones(nels,1);
21 20
22 # Find non-zero elements in the input matrix. 21 # Find non-zero elements in the input matrix.
23 i = find(x); 22 i = find(x);
24 23
25 if (!isempty(i)) 24 if (!isempty(i))
26 result(i) = sin(pi*x(i))./(pi*x(i)); 25 result(i) = sin(pi*x(i))./(pi*x(i));
27 endif 26 endif