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1 function y = conv(a,b) |
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2 #Convolve two vectors. |
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3 #y = conv(a,b) returns a vector of length equal to length(a)+length(b)-1. |
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4 #If a and b are polynomial coefficient vectors, conv returns the |
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5 #coefficients of the product polynomial. |
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6 # |
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7 #SEE ALSO: deconv, poly, roots, residue, polyval, polyderiv, polyinteg |
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8 |
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9 # Author: |
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10 # Tony Richardson |
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11 # amr@mpl.ucsd.edu |
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12 # June 1994 |
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13 |
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14 if(nargin != 2) |
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15 error("usage: conv(a,b)"); |
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16 endif |
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17 |
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18 if(is_matrix(a) || is_matrix(b)) |
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19 error("conv: both arguments must be vectors"); |
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20 endif |
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21 |
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22 la = length(a); |
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23 lb = length(b); |
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24 |
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25 ly = la + lb - 1; |
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26 |
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27 # Ensure that both vectors are row vectors. |
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28 if(rows(a) > 1) |
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29 a = reshape(a,1,la); |
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30 endif |
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31 if(rows(b) > 1) |
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32 b = reshape(b,1,lb); |
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33 endif |
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34 |
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35 # Use the shortest vector as the coefficent vector to filter. |
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36 if (la < lb) |
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37 if(ly>lb) |
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38 x = [b zeros(1,ly-lb)]; |
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39 else |
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40 x = b; |
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41 endif |
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42 y = filter(a,1,x); |
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43 else |
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44 if(ly>la) |
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45 x = [a zeros(1,ly-la)]; |
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46 else |
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47 x = a; |
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48 endif |
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49 y = filter(b,1,x); |
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50 endif |
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51 |
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52 endfunction |
