為什么此高斯函數會給出不一致的參數錯誤？

Question

function m=gaussian(med, var, n)
  if ( mod(n, 2)==0 )
      n=n+1;
  end;

  med=double(med);
  var=double(var);

  med = min (max(-(n+1)/2, med),  (n+1)/2);

  m=zeros(1,n);

  k1=(1/(2*pi*var)^0.5);
  k2=-0.5.*((med-(1:n)).^2)./var;

  m(1,1:n)=k1.*exp(k2);

輸出1

>> gaussian([101 2 ; 3 4], [4 301 ; 2 1], [2 2])
error: gaussian: operator /: nonconformant arguments (op1 is 1x1, op2 is 2x2)
error: called from
    gaussian at line 13 column 5
>>

輸出2

>> gaussian([101 2 ; 3 4], [4 301 ; 2 1], 2)
error: gaussian: operator /: nonconformant arguments (op1 is 1x1, op2 is 2x2)
error: called from
    gaussian at line 13 column 5

Answer 1

我不確定您想要的結果是什么，但是會收到該錯誤，因為您正在用[2x2]矩陣對標量（ [1x1]尺寸）進行矩陣除法 。 請注意，您正在執行矩陣除法（ /運算符），而不是逐個元素除法（ ./運算符）。

octave:1> function m=gaussian(med, var, n)
>   if ( mod(n, 2)==0 )
>       n=n+1;
>   end;
> 
>   med=double(med);
>   var=double(var);
> 
>   med = min (max(-(n+1)/2, med),  (n+1)/2);
> 
>   m=zeros(1,n);
> 
>   k1=(1/(2*pi*var)^0.5);
>   k2=-0.5.*((med-(1:n)).^2)./var;
> 
>   m(1,1:n)=k1.*exp(k2);
> endfunction
octave:2> debug_on_error (1)
octave:3> gaussian ([101 2 ; 3 4], [4 301 ; 2 1], 2)
error: gaussian: operator /: nonconformant arguments (op1 is 1x1, op2 is 2x2)
error: called from
    gaussian at line 13 column 5
stopped in gaussian at line 13
13:   k1=(1/(2*pi*var)^0.5);
debug> (2*pi*var)
ans =

     25.1327   1891.2388
     12.5664      6.2832

debug> 1/(2*pi*var) # matrix division
error: gaussian: operator /: nonconformant arguments (op1 is 1x1, op2 is 2x2)
error: called from
    gaussian at line 13 column 5
debug> 1./(2*pi*var) # your element by element division works
ans =

   0.03978874   0.00052875
   0.07957747   0.15915494

但是，這不是唯一的問題，因為以下行的減號運算符也有類似的問題：

error: gaussian: operator -: nonconformant arguments (op1 is 2x2, op2 is 1x3)
error: called from
    gaussian at line 14 column 5
stopped in gaussian at line 14
14:   k2=-0.5.*((med-(1:n)).^2)./var;

或者，函數可能不正確，並且由於錯誤地調用了函數而出現了這些錯誤。