increase factorial execution speed

Hello there

I'm attempting to use the prod function to construct the factorial code more quickly, but I'm encountering a problem.

Please let me know the reason for this and what I might be doing incorrectly.

Many thanks

n = fi(1); % n max is 20

n = 
     1

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 14

indx = max(1,max(min(n,20)));
for g = 1:indx
    out(:) = prod(1:indx,'all');
end

Error using prod
Invalid data type. First argument must be numeric or logical.

Answer 1

[Chunru]

n = 5     % n max is 20

n = 5

out = cumprod(1:n)

out = 1×5

1 2 6 24 120

n = fi(5); % n max is 20
out = (1:n);
for i = 2:n
     out(i) = out(i-1)*i;
end
out

out = 
     1     2     6    24   120

          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 16
        FractionLength: 0

[Life is Wonderful]

How ?

Error is due to "Invalid data type" and not in due to prod.

[Chunru]

You use "fi", or fixed point format. The prod function does not support the data type.

In above, I use double type for all data.

[Life is Wonderful]

You see Error,

n = fi(1); % n max is 20
indx = max(1,max(min(n,20)));
for g = 1:indx
    out(:) = cumprod(1:indx);
end

Error using cumprod
Invalid data type. First input argument must be numeric or logical.

[Life is Wonderful]

Yes, I did specify that the code I'm using is fixed point rather than double.

Do you have another suggestion?

[Chunru]

See above for the fi data type.

[Life is Wonderful]

Thanks a lot,