Round Function in Cognos olap

[cognos05]

Hi ,

I have a visualization which is erroring out if i supply value like

-0.00004

so i have to round the value to 3 decimals .

I tried using round , but it says not supported in context used, my source is olap

i dont want to round up or round down

so how can i do around on my data item

[cognos05]

_round() worked