Messages in this thread | | | Subject | Re: [PATCH] staging: iio: tsl2x7x_core: Fix standard deviation calculation | From | Jonathan Cameron <> | Date | Sat, 25 Mar 2017 16:48:10 +0000 |
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On 20/03/17 11:27, Eva Rachel Retuya wrote: > Standard deviation is calculated as the square root of the variance > where variance is the mean of sample_sum and length. Correct the > computation of statP->stddev in accordance to the proper calculation. > > Fixes: 3c97c08b5735 ("staging: iio: add TAOS tsl2x7x driver") > Reported-by: Abhiram Balasubramanian <abhiram@cs.utah.edu> > Signed-off-by: Eva Rachel Retuya <eraretuya@gmail.com> I've applied this to the togreg branch of iio.git rather than sending as a quick fix for the simple reason that nothing currently uses the value once it has been computed that I can immediately see!
That whole chunk of code probably just wants to be ripped out in the longer term.
Jonathan > --- > drivers/staging/iio/light/tsl2x7x_core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/staging/iio/light/tsl2x7x_core.c b/drivers/staging/iio/light/tsl2x7x_core.c > index ea15bc1..197201a 100644 > --- a/drivers/staging/iio/light/tsl2x7x_core.c > +++ b/drivers/staging/iio/light/tsl2x7x_core.c > @@ -854,7 +854,7 @@ void tsl2x7x_prox_calculate(int *data, int length, > tmp = data[i] - statP->mean; > sample_sum += tmp * tmp; > } > - statP->stddev = int_sqrt((long)sample_sum) / length; > + statP->stddev = int_sqrt((long)sample_sum / length); > } > > /** >
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