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1 function [xb, yb] = bar (x, y) |
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2 |
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3 # usage: [xb, yb] = bar (x, y) |
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4 # |
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5 # Given two vectors of x-y data, bar produces a bar graph. |
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6 # |
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7 # If only one argument is given, it is taken as a vector of y-values |
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8 # and the x coordinates are taken to be the indices of the elements. |
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9 # |
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10 # If two output arguments are specified, the data are generated but |
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11 # not plotted. For example, |
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12 # |
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13 # bar (x, y); |
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14 # |
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15 # and |
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16 # |
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17 # [xb, yb] = bar (x, y); |
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18 # plot (xb, yb); |
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19 # |
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20 # are equivalent. |
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21 # |
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22 # See also: plot, semilogx, semilogy, loglog, polar, mesh, contour, |
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23 # stairs, gplot, gsplot, replot, xlabel, ylabel, title |
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24 |
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25 if (nargin == 1) |
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26 if (is_vector (x)) |
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27 len = 3 * length (x) + 1; |
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28 xb = yb = zeros (len, 1); |
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29 xb(1) = 0.5; |
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30 yb(1) = 0; |
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31 k = 1; |
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32 for i = 2:3:len |
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33 xb(i) = k-0.5; |
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34 xb(i+1) = k+0.5; |
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35 xb(i+2) = k+0.5; |
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36 yb(i) = x(k); |
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37 yb(i+1) = x(k); |
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38 yb(i+2) = 0.0; |
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39 k++; |
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40 endfor |
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41 else |
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42 error ("bar: argument must be a vector"); |
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43 endif |
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44 elseif (nargin == 2) |
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45 if (is_vector (x) && is_vector (y)) |
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46 xlen = length (x); |
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47 ylen = length (y); |
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48 if (xlen == ylen) |
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49 len = 3 * xlen + 1; |
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50 xb = yb = zeros (len, 1); |
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51 delta = (x(2) - x(1)) / 2.0; |
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52 xb(1) = x(1) - delta; |
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53 yb(1) = 0.0; |
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54 k = 1; |
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55 for i = 2:3:len |
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56 xb(i) = xb(i-1); |
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57 xb(i+1) = xb(i) + 2.0 * delta; |
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58 xb(i+2) = xb(i+1); |
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59 yb(i) = y(k); |
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60 yb(i+1) = y(k); |
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61 yb(i+2) = 0.0; |
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62 if (k < xlen) |
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63 delta = (x(k+1) - x(k)) / 2.0; |
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64 if (x(k+1) < x(k)) |
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65 error ("bar: x vector values must be in ascending order"); |
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66 endif |
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67 endif |
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68 k++; |
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69 endfor |
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70 else |
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71 error ("bar: arguments must be the same length"); |
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72 endif |
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73 else |
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74 error ("bar: arguments must be vectors"); |
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75 endif |
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76 else |
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77 error ("usage: [xb, yb] = bar (x, y)"); |
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78 endif |
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79 |
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80 if (nargout == 1) |
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81 plot (xb, yb); |
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82 endif |
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83 |
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84 endfunction |