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Hi,
I got result 1.#QNAN00000000 and -1.#IND000000000 in my programme, what
happened?
why?
Thanks.

fcvcnet wrote:
> Hi,
> I got result 1.#QNAN00000000 and -1.#IND000000000 in my programme, what
> happened?
> why?

If you can post your code then it might be more easy to find the
problem.

"fcvcnet" <> wrote in message
news:ei9ndm$5lf$...
> Hi,
> I got result 1.#QNAN00000000 and -1.#IND000000000 in my programme, what
> happened?
> why?
> Thanks.

NAN is not a number. This can happen with a floating point math won't work.
In some cases dividing by 0 will produce a NAN, but in others it produces
infinity (not sure if the specs say whiat it should produce).

Not sure what IND is. It may be infinity, but I would think that would be
INF, so I'm not sure.

Jim Langston <> wrote:
> "fcvcnet" <> wrote in message
> news:ei9ndm$5lf$...
>> Hi,
>> I got result 1.#QNAN00000000 and -1.#IND000000000 in my programme, what
>> happened?
>> why?
>> Thanks.
>
> NAN is not a number. This can happen with a floating point math won't work.
> In some cases dividing by 0 will produce a NAN, but in others it produces
> infinity (not sure if the specs say whiat it should produce).
>
> Not sure what IND is. It may be infinity, but I would think that would be
> INF, so I'm not sure.

I'm not sure either, but IND might mean "indeterminate". As in,
(informally) 1/0 is infinity but 0/0 is indeterminate.

http://mathworld.wolfram.com/Indeterminate.html

--
Marcus Kwok
Replace 'invalid' with 'net' to reply

fcvcnet wrote:
> Hi,
> I got result 1.#QNAN00000000 and -1.#IND000000000 in my programme, what
> happened?
> why?
> Thanks.

recently I had to do some experimentation with this stuff, here's some
code and the output


float pinf = std::numeric_limits<float>::infinity();
double dpinf = std::numeric_limits<double>::infinity();

float ninf = -std::numeric_limits<float>::infinity();
float zero = 0.0;
float NaN = std::numeric_limits<float>::quiet_NaN();
float nNaN = -std::numeric_limits<float>::quiet_NaN();
double dNaN = std::numeric_limits<double>::quiet_NaN();

float xNaN = static_cast<float>(dNaN);

std::cout << "+ve infinity " << pinf << "\n";
std::cout << "-ve infinity " << ninf << "\n";
std::cout << "+ve QNAN " << NaN << "\n";
std::cout << "+ve dQNAN " << dNaN << "\n";
std::cout << "+ve xQNAN " << xNaN << "\n";
std::cout << "-ve QNAN " << nNaN << "\n";
std::cout << "+inf = +inf " << (pinf == pinf) << "\n";
std::cout << "+inf <= +inf " << (pinf <= pinf) << "\n";
std::cout << "+inf = +dinf " << (pinf == dpinf) << "\n";
std::cout << "+inf = -inf " << (pinf == ninf) << "\n";
std::cout << "+inf / +inf " << pinf/pinf << "\n";
std::cout << "+inf / -inf " << pinf/ninf << "\n";
std::cout << "+inf / zero " << pinf/zero << "\n";
std::cout << "+inf * -inf " << pinf*ninf << "\n";
std::cout << "+inf + -inf " << pinf+ninf << "\n";
std::cout << "+inf + +inf " << pinf+pinf << "\n";
std::cout << "+inf - -inf " << pinf-ninf << "\n";
std::cout << "+inf - +inf " << pinf-pinf << "\n";
std::cout << "-inf - -inf " << ninf-ninf << "\n";
std::cout << "\n\n";
std::cout << "NaN = NaN " << (NaN == NaN) << "\n";
std::cout << "-NaN = -NaN " << (nNaN == nNaN) << "\n";
std::cout << "-NaN = NaN " << (nNaN == NaN) << "\n";
std::cout << "NaN = -NaN " << (NaN == nNaN) << "\n";
std::cout << "NaN = +inf " << (NaN == pinf) << "\n";
std::cout << "NaN = -inf " << (NaN == ninf) << "\n";
std::cout << "0 / zero " << 0/zero << "\n";

+ve infinity 1.#INF
-ve infinity -1.#INF
+ve QNAN 1.#QNAN
+ve dQNAN 1.#QNAN
+ve xQNAN 1.#QNAN
-ve QNAN -1.#IND
+inf = +inf 1
+inf <= +inf 1
+inf = +dinf 1
+inf = -inf 0
+inf / +inf -1.#IND
+inf / -inf -1.#IND
+inf / zero 1.#INF
+inf * -inf -1.#INF
+inf + -inf -1.#IND
+inf + +inf 1.#INF
+inf - -inf 1.#INF
+inf - +inf -1.#IND
-inf - -inf -1.#IND


NaN = NaN 0
-NaN = -NaN 0
-NaN = NaN 0
NaN = -NaN 0
NaN = +inf 0
NaN = -inf 0
0 / zero -1.#IND

Meant to say, results are from gcc on pentium, and seem to agree with
IEEE 754. VC 6.0 results differ for some cases, VC 7.0 is the same as
gcc.

Thanks you very much.

"Geo" <>
??????: ups.com...
> Meant to say, results are from gcc on pentium, and seem to agree with
> IEEE 754. VC 6.0 results differ for some cases, VC 7.0 is the same as
> gcc.
>

Thanks you very much.
"Marcus Kwok" <> дÈëÏûÏ¢ÐÂÎÅ:eiagra$8dp$...
> Jim Langston <> wrote:
>> "fcvcnet" <> wrote in message
>> news:ei9ndm$5lf$...
>>> Hi,
>>> I got result 1.#QNAN00000000 and -1.#IND000000000 in my programme,
>>> what
>>> happened?
>>> why?
>>> Thanks.
>>
>> NAN is not a number. This can happen with a floating point math won't
>> work.
>> In some cases dividing by 0 will produce a NAN, but in others it produces
>> infinity (not sure if the specs say whiat it should produce).
>>
>> Not sure what IND is. It may be infinity, but I would think that would
>> be
>> INF, so I'm not sure.
>
> I'm not sure either, but IND might mean "indeterminate". As in,
> (informally) 1/0 is infinity but 0/0 is indeterminate.
>
> http://mathworld.wolfram.com/Indeterminate.html
>
> --
> Marcus Kwok
> Replace 'invalid' with 'net' to reply

Thanks you very much.

"Jim Langston" <> дÈëÏûÏ¢ÐÂÎÅ:Cz_1h.69$...
> "fcvcnet" <> wrote in message
> news:ei9ndm$5lf$...
>> Hi,
>> I got result 1.#QNAN00000000 and -1.#IND000000000 in my programme,
>> what happened?
>> why?
>> Thanks.
>
> NAN is not a number. This can happen with a floating point math won't
> work. In some cases dividing by 0 will produce a NAN, but in others it
> produces infinity (not sure if the specs say whiat it should produce).
>
> Not sure what IND is. It may be infinity, but I would think that would be
> INF, so I'm not sure.
>

Marcus Kwok
Thanks you very much.
your url
http://mathworld.wolfram.com/Indeterminate.html

is very useful!
Thanks again!