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1 function retval = logspace (x1, x2, n) |
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2 |
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3 # usage: logspace (x1, x2, n) |
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4 # |
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5 # Return a vector of n logarithmically equally spaced points between |
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6 # x1 and x2 inclusive. |
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7 # |
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8 # If the final argument is omitted, n = 50 is assumed. |
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9 # |
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10 # All three arguments must be scalars. |
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11 # |
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12 # Note that if if x2 is pi, the points are between 10^x1 and pi, NOT |
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13 # 10^x1 and 10^pi. |
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14 # |
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15 # Yes, this is pretty stupid, because you could achieve the same |
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16 # result with logspace (x1, log10 (pi)), but Matlab does this, and |
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17 # claims that is useful for signal processing applications. |
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18 # |
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19 # See also: linspace |
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20 |
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21 if (nargin == 2) |
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22 npoints = 50; |
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23 elseif (nargin == 3) |
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24 if (length (n) == 1) |
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25 npoints = n; |
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26 else |
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27 error ("logspace: arguments must be scalars"); |
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28 endif |
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29 else |
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30 error ("usage: logspace (x1, x2 [, n])"); |
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31 endif |
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32 |
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33 if (npoints < 2) |
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34 error ("logspace: npoints must be greater than 2"); |
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35 endif |
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36 |
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37 if (length (x1) == 1 && length (x2) == 1) |
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38 x2_tmp = x2; |
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39 if (x2 == pi) |
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40 x2_tmp = log10 (pi); |
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41 endif |
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42 retval = linspace (x1, x2_tmp, npoints); |
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43 for i = 1:npoints |
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44 retval(i) = 10 ^ retval(i); |
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45 endfor |
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46 else |
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47 error ("logspace: arguments must be scalars"); |
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48 endif |
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49 |
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50 endfunction |
