I get the following, on an Ubuntu 64-bit VM (edited to fit the page 
width):

prime.rb:44: warning: assigned but unused variable - rescnt
prime.rb:85: warning: assigned but unused variable - rescnt
prime.rb:119: warning: assigned but unused variable - rescnt
prime.rb:159: warning: assigned but unused variable - rescnt
prime.rb:165: warning: assigned but unused variable - modk
prime.rb:212: warning: shadowing outer local variable - p
Rehearsal -------------------------------------------------
prime tests for P = 20000000000000003
Miller-Rabin    0.000000   0.000000   0.000000 (  0.000761)
primzp7?        2.290000   0.000000   2.290000 (  2.294709)
primzp7a?       0.970000   0.000000   0.970000 (  0.971033)
primzp7b?       0.980000   0.000000   0.980000 (  0.978331)
primzp? 13      1.900000   0.010000   1.910000 (  1.905374)
primzp? 17      1.870000   0.000000   1.870000 (  1.877343)
primzpa? 13     3.200000   0.050000   3.250000 (  3.255519)
primzpa? 17     3.100000   0.040000   3.140000 (  3.127512)
factorzp 13     1.940000   0.000000   1.940000 (  1.949376)
factorzp 17     1.870000   0.000000   1.870000 (  1.870068)
prime? [ruby lib]
                26.550000   0.010000  26.560000 ( 26.569130)
prime_division [ruby lib]
                29.570000   0.000000  29.570000 ( 29.585618)
---------------------------------------- total: 74.350000sec

                user     system      total        real
prime tests for P = 20000000000000003
Miller-Rabin    0.000000   0.000000   0.000000 (  0.000562)
primzp7?        2.320000   0.000000   2.320000 (  2.319329)
primzp7a?       0.980000   0.000000   0.980000 (  0.974572)
primzp7b?       0.980000   0.000000   0.980000 (  0.984110)
primzp? 13      1.920000   0.000000   1.920000 (  1.923894)
primzp? 17      1.880000   0.010000   1.890000 (  1.884494)
primzpa? 13     3.080000   0.030000   3.110000 (  3.109670)
primzpa? 17     3.010000   0.020000   3.030000 (  3.028406)
factorzp 13     1.910000   0.000000   1.910000 (  1.917429)
factorzp 17     1.880000   0.000000   1.880000 (  1.875251)
prime? [ruby lib]
                25.170000   0.000000  25.170000 ( 25.177364)
prime_division [ruby lib]
                28.270000   0.020000  28.290000 ( 28.298034)

[Kiswono Prayogo, note the durations, especially in the core methods; 
10s is too short for calculating primality of large numbers. Have 
patience.]

Note that all the warnings can be resolved by removing the unused 
definitions, and renaming that 'p' variable in the block.  They're 
messy, but unimportant.

-- 
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