Error using ==> mpower At least one operand must be scalar in mod operation
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hi all, i need ur little help here. i use this code
d=18;
n=19;
x=3;
d1=dec2bin(d);
r=1;
for i=1:length(d1)
r=mod((r^r),n);
if (d1(i)>=1)
r=r*(mod(x,n));
end
end
it's return this error: ??? Error using ==> mpower At least one operand must be scalar.
Error in ==> geje at 26
r=mod((r^r),n);
i don't know where is my mistake?? hope your solution
回答（4 个）
zikrullah muhammad
2011-6-26
0 个投票
2 个评论
Paulo Silva
2011-6-26
Run the code like this and see what appears on the command line
d=18;
n=19;
x=3;
d1=dec2bin(d);
r=1;
for i=1:length(d1)
r
n
r=mod((r^r),n)
if (d1(i)>=1)
r=r*(mod(x,n));
end
end
zikrullah muhammad
2011-6-27
Matt Fig
2011-6-26
0 个投票
There is more going on here than you say, because the code you pasted could not possibly have that error. The variable 'r' is a scalar going into the loop. Since 'x' and 'n' (both scalars) don't change in the loop, mod(x,n) is always 3. So the only way 'r' is changed, besides the line in question, is possibly by a factor of 3. A scalar multiplied by 3 is always a scalar, and so 'r' has no chance of not being a scalar. Since both operands passed to MPOWER are scalar, there can be no error.
Thus the code you show couldn't possibly have this error, assuming you haven't masked any built-in functions. So what have you left out of your post?
And by the way, please don't post new 'answers' when you are responding to an answer given by someone else. Instead, put a comment on their answer by clicking the "Comment on this Answer" link.
Walter Roberson
2011-6-26
0 个投票
r^r is an error if r is not a scalar.
MATLAB knows how to raise a square matrix to a scalar power, and knows how to raise a scalar to a matrix power, but MATLAB cannot raise a matrix to a matrix power.
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2011-6-26
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