How to get stats command to calculate with precision for numbers in scientific notation?

[dmr195]

I have found that the stats command's output doesn't use scientific notation. This means that if I need to calculate some statistics on a set of very small numbers then stats just reports 0.00000.

You can see the effect with this search:

| stats count | eval small="1.23456e-306" | stats min(small)

It will always return 0.00000.

Is there a way to have the stats command in the above search keep the precision and return 1.23456e-306?

(I know in this example the stats command is pointless because there's only one value, but the real case is that I have many events containing very small numbers and I want to calculate various statistics of the data set without all the small numbers getting changed to 0.)

[dmr195]

A possibility for getting around the loss of precision in stats is to take logarithms before the stats command and then convert back afterwards. This works quite well:

| stats count | eval small="1.23456e-304" | eval lnsmall=ln(small) | stats min(lnsmall) as minlnsmall | eval minsmall=if(minlnsmall<-702.0, 0, exp(minlnsmall*1.0))

The check for minlnsmall being less than -702 is needed to avoid nan being returned close to the limits of double precision floating point accuracy, and it's necessary to multiply minlnsmall by 1.0 rather than 1 otherwise some premature rounding occurs sometimes (but not always).

[somesoni2 · Accepted solution]

Try something like this

| stats count | eval small="1.23456e-30" | eval small=small*1 | stats min(small)

PS: The example value that you gave little too small so changed to little big number.

[dmr195]

Another interesting thing is that eval can handle the full double precision accuracy, for example:

| stats count | eval small="1.23456e-303" | eval small=small*1

prints small with 308 digits to the right of the decimal point.

So it seems like it's the stats command that's limited to 125 decimal places.

[dmr195]

It seems like 125 digits to the right of the decimal point is the most that's possible. So:

| stats count | eval small="1.23456e-125" | eval small=small*1 | stats min(small)

goes to:

0.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001

and:

| stats count | eval small="1.23456e-126" | eval small=small*1 | stats min(small)

loses all precision and prints 0.

This is a shame as the smallest double precision floating point number is 2.2e-308. But with I'm better off than I was originally, so thanks for the answer!