perm_test: Tests whether each row in f(x) is equal to 0 using...
In agentlans/CorTools: Permutation Tests On Correlation And Regression

Tests whether each row in f(x) is equal to 0 using permutation test

1	perm_test(f, x, x.rand = function() sample(x), n = 1000)

`f`	function that takes x and produces a vector (must have the same names in same order in every trial!)
`x`	value of x such that f(x) gives observed value
`x.rand`	function that takes no arguments and gives random value of x under null hypothesis
`n`	number of trials