fixed docstring in rand momenta test implementation, fixed bug in all…

…-fail rand momenta

test/test_implementation/random_momenta.jl

@@ -58,14 +58,15 @@ i.e. their first entries are null momenta.
 """
 function _rand_in_momenta_failed_all(rng::AbstractRNG, N1, N2)
     moms = _rand_momenta(rng, N1, N2)
-    moms[1, 1] = zero(SFourMomentum)
-    moms[1, 2] = zero(SFourMomentum)
+    for n in 1:N2
+        moms[1, n] = zero(SFourMomentum)
+    end
     return moms
 end
 
 """
-Return a collection of outgoing space points, where the first point is failing the phase space constraint, 
-i.e. the first entry of the matrix is the null momentum, but the others pass. 
+Return a collection of outgoing phase space points, where the first point is failing the phase space constraint, 
+i.e. the last entry of the matrix is the unit momentum, but the others pass. 
 """
 function _rand_out_momenta_failed_mix(rng::AbstractRNG, N1, N2)
     moms = _rand_momenta(rng, N1, N2)
@@ -75,11 +76,12 @@ end
 
 """
 Return a collection of outgoing phase space points, where all points are failing the phase space constraint, 
-i.e. their first entries are null momenta.
+i.e. their last entries are unit momenta.
 """
 function _rand_out_momenta_failed_all(rng::AbstractRNG, N1, N2)
     moms = _rand_momenta(rng, N1, N2)
-    moms[end, 1] = ones(SFourMomentum)
-    moms[end, 2] = ones(SFourMomentum)
+    for n in 1:N2
+        moms[end, n] = ones(SFourMomentum)
+    end
     return moms
 end