strange output

[mp]

When printing a floating math result I sometimes get the following:

-1.#IND00

Can anyone tell what this means and how to avoid it?

Thank you,

[Joe Wright]

mp wrote:

When printing a floating math result I sometimes get the following:

-1.#IND00

Can anyone tell what this means and how to avoid it?

Thank you,

It doesn't mean anything to me. Can you give us more detail, some code
perhaps.

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Jordan Abel]

On 2006-03-09, mp <mp****@wisc.edu> wrote:

When printing a floating math result I sometimes get the following:

-1.#IND00

Can anyone tell what this means and how to avoid it?

Thank you,

<wild speculation>
Negative infinity?

[mp]

I am new to C.
This function is used to calculate a basic F-statistic.
Most of the time it works fine, once in a while it will fail with
several values
set to -1.#IND00.

double calcF(int *marker, int *groups, double *groupmean, double
*pheno, int numStrains, int Largest, double totalmean)
{
int gpctr = 0; // group iterator
/******************** Count number in each group
***************************/
int m = 0;
int tmp = 0;
for(gpctr = 1; gpctr<=Largest; gpctr++)
{ tmp = 0;
for(m=0;m<numStrains;m++)
{
if( gpctr == marker[m] )
{
tmp++;
}

}

}

/***************** Calc mean for each group ***********************/
double tmpsum = 0.0;
for(gpctr = 1; gpctr<=Largest; gpctr++)
{
tmpsum = 0.0;
for(m=0;m<numStrains;m++)
{
if( gpctr == marker[m])
{
tmpsum += pheno[m];
}
groupmean[gpctr] = (tmpsum/groups[gpctr]);

}

}
/************************************************** ***************/

double sstot = 0.0; //sum of squares total
double ssbet = 0.0; //sum of squares between
double ssw = 0.0; //sum of squares within
double dfbet = 0.0; // degrees of freedom between
double dfw = 0.0; // degrees of freedom within
double f = 0.0; // F-statistic

/******** CALC sum of square total *********/
double sstmp = 0.0;
for(m=0;m<numStrains;m++)
{
sstmp += ((pheno[m] - totalmean) * (pheno[m] - totalmean) );

}
sstot = sstmp;

/******** CALC sum of square between *********/
sstmp = 0.0;

for(gpctr = 1; gpctr<=Largest; gpctr++)
{
sstmp += ((groupmean[gpctr] - totalmean) *
(groupmean[gpctr] - totalmean));
}
ssbet = sstmp; //########## THIS SOMETIMES SET TO -1.#IND00
/******** CALC sum of square within *********/

if( ssbet == 0)
{
ssw = sstot;
}else{
ssw = sstot - ssbet;
}
/******** CALC degrees of freedom *********/

dfbet = (Largest - 1);
dfw = (numStrains - Largest);
/******** Calc F-statistic ************************/
if(ssw == 0 || dfbet == 0 || dfw == 0 || ssbet == 0)
{
return f = 1000.1;
}else{

f = (ssbet/dfbet)/(ssw/dfw);

return f;
}

[pemo]

mp wrote:

When printing a floating math result I sometimes get the following:

-1.#IND00

Can anyone tell what this means and how to avoid it?

Thank you,

Don't know, but I get 99,300 hits for #IND00 from Google.

--
==============
*Not a pedant*
==============