尝试在MATLAB中计算功效时出错

Question

I have this function in matlab-

function [c,arr2]=dist1(i,c,arr1,arr2,A,mx,point)      
    for j=i+1:mx
        if arr1(i,j)==1 & A(j)~=0
            x1=point(i,1);
            y1=point(i,2);
            x2=point(j,1);
            y2=point(j,2);
            d=((((x1-x2).^2)+((y1-y2).^2)).^(0.5));
            if d< 0.5
                arr2(c)=i;
                c=c+1;
                [c,arr2]=dist1(j,c,arr1,arr2,A,mx,point);
            end
        end
    end
end

When I call this function this function I get following error-

Integers can only be raised to positive integral powers.

Error in dist1 (line 9)
            d=((((x1-x2).^2)+((y1-y2).^2)).^(0.5));

This works fine if I remove power of 0.5 in the calculation of d .Why am I getting this error,there seems to be nothing wrong in this statement.Also I checked the values of x1,x2,y1,y2 in the preceding lines and they are

x1=208 y1=171 x2=207 y2=162

Answer 1

The error is pretty explicit:

Integers can only be raised to positive integral powers.

Your x1 , x2 , y1 , y2 variables seem to be of an integer data type (such as uint8 , int32 , ...). They need to be double (or single ) to perform that operation. So, try

d = double((((x1-x2).^2)+((y1-y2).^2)).^(0.5))^0.5;

Note also that, since x1 , x2 , y1 , y2 are scalars, you could remove the dots:

d = double((((x1-x2)^2)+((y1-y2)^2))^0.5)^0.5;