Off topic:How to make R display very small p-values?

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Hi all,

I am using a built-in function to calculate p-values for a set of genes. However, as an output, for some of the genes I am getting 0. I think its because the number is too small and R outputs it as 0. Any suggestions on how can I get over this? The line where p-value is calculated in function is

p = pchisq(df=df_brown, q=x/c, lower.tail=FALSE)

I came across "Rmpfr" package and then tried to implement it. But the resulting p-value is still 0.

 p = mpfr(pchisq(df=df_brown, q=x/c, lower.tail=FALSE), 120)

Any leads would be highly appreciated. Thanks.