force fixed format

If the issue [of suppressing scientific notation] is general, try the scipen
option:

 > options(scipen=10)
 > p <- 0.0001
 > p

[1] 0.0001

To explain further: R normally prints in scientific notation if it requires
fewer characters than standard notation.  By setting options(scipen=10), you
are imposing an addition 10-character SCIentific notation PENalty whenever this
comparison is made.  Negative values would favor scientific notation.

-- David Brahm (brahm at alum.mit.edu)