Question

polyfit函数需要多项式度n的标量值，例如

P = polyfit(X, Y, 3)

表明应该使用for循环来确定适合相同曲线的多项式范围（比如2度到4度）：

% Fit a given curve with a series of polynomials
% of given degrees

X = 1:6; % Range of x in the sample
Y0 = [10, 11, 21, 2, 3, 7]; % Sample
DEG = 2:6; % Degrees to use for polynomials

plot(X, Y0) % Plot sample for reference
for n = DEG
  hold on
  P = polyfit(X, Y0, n); % Fitting polynomial, degree n
  Y = polyval(P, X); % Compute y for this polynomial
  plot(X, Y)
endfor

有没有办法简化此代码并将其转换为＆＃39;所有数组＆＃39;通过在函数中直接使用范围DEG？我在polyfit(X, Y0, DEG)附近尝试了几种变体，但Octave一直告诉我：

error: polyfit: N must be a non-negative integer

任何帮助表示感谢。

Answer 1

这是arrayfun的用途：

octave:1> X = 1:6;
octave:2> Y0 = [10, 11, 21, 2, 3, 7];
octave:3> DEG = 2:6;
octave:4> arrayfun (@(n) polyfit (X, Y0, n), DEG, "UniformOutput", false)
ans =
{
  [1,1] =

     -0.37500    0.96786   11.30000

  [1,2] =

      1.0833  -11.7500   35.3095  -16.0000

  [1,3] =

      0.43750   -5.04167   17.43750  -18.94048   15.50000

  [1,4] =

      -1.2750    22.7500  -150.9583   456.2500  -612.7667   296.0000

  [1,5] =

     -0.31438    5.32693  -32.26604   80.10905  -54.29889  -58.20494   69.64828

}

对于参数N，我可以使用范围而不是标量的polyfit吗？

1 个答案: