peasant algorithm

First version 3 loops / every one populate one column 

r = Peasant.new(1233, 3000)
r2 = Peasant.new(1344718,9539271)
r3 =  Peasant.new(2345642233123, 1234567890987)

Benchmark.bm do |x|
   x.report("4dig: "){ r.multiply }
   x.report("7dig: "){ r2.multiply }
   x.report("13dig: ") {r3.multiply}
end

          user     system      total        real
4dig:   0.000000   0.000000   0.000000 (  0.000053)
7dig:   0.000000   0.000000   0.000000 (  0.000057)
13dig:  0.000000   0.000000   0.000000 (  0.000127)

       user     system      total        real
4dig:   0.000000   0.000000   0.000000 (  0.000054)
7dig:   0.000000   0.000000   0.000000 (  0.000046)
13dig:   0.000000   0.000000   0.000000 (  0.000093)


        user     system      total        real
4dig:   0.000000   0.000000   0.000000 (  0.000085)
7dig:   0.000000   0.000000   0.000000 (  0.000054)
13dig:  0.000000   0.000000   0.000000 (  0.000164)


Second version reducing loops

reference values
r = Peasant.new(1234567890987654321, 1098765432123456789)
r2 =  Peasant.new(123456789098765432123456789, 909876543212345678909876543)

n= 5000
Benchmark.bm do |x|
 x.report("19dnew:"){ for i in 1..n; r = Peasant.new(1234567890987654321, 1098765432123456789); r.multiply; end}
 x.report("27dnew:"){ for i in 1..n; r2 = Peasant.new(123456789098765432123456789, 909876543212345678909876543); r2.multiply; end} 
 x.report("19dold:"){ for i in 1..n; rold = Peasant.new(1234567890987654321, 1098765432123456789); rold.multiply_old; end}
 x.report("27dold:"){ for i in 1..n; r2old = Peasant.new(123456789098765432123456789, 909876543212345678909876543); r2old.multiply_old; end}
end

       user     system      total        real
19dnew:  0.230000   0.000000   0.230000 (  0.236329)
27dnew:  0.370000   0.000000   0.370000 (  0.371231)
19dold:  0.230000   0.000000   0.230000 (  0.225444)
27dold:  0.390000   0.000000   0.390000 (  0.399403)


** complete comparison **
##### v1 = first approach
##### old = reducing loop
##### multiply = last approach


n= 5000
Benchmark.bm do |x|
 x.report("19dnew:"){ for i in 1..n; r = Peasant.new(1234567890987654321, 1098765432123456789); r.multiply; end}
 x.report("27dnew:"){ for i in 1..n; r2 = Peasant.new(123456789098765432123456789, 909876543212345678909876543); r2.multiply; end} 
 x.report("19dold:"){ for i in 1..n; rold = Peasant.new(1234567890987654321, 1098765432123456789); rold.multiply_old; end}
 x.report("27dold:"){ for i in 1..n; r2old = Peasant.new(123456789098765432123456789, 909876543212345678909876543); r2old.multiply_old; end}
 x.report("19dv1:"){ for i in 1..n; rv1 = Peasant.new(1234567890987654321, 1098765432123456789); rv1.multiply_v1; end}
 x.report("27dv1:"){ for i in 1..n; r2v1 = Peasant.new(123456789098765432123456789, 909876543212345678909876543); r2v1.multiply_v1; end}
end

       user     system      total        real
19dnew:  0.240000   0.000000   0.240000 (  0.236432)
27dnew:  0.390000   0.000000   0.390000 (  0.390416)
19dold:  0.230000   0.000000   0.230000 (  0.236033)
27dold:  0.400000   0.000000   0.400000 (  0.398432)
19dv1:  0.260000   0.000000   0.260000 (  0.259945)
27dv1:  0.440000   0.000000   0.440000 (  0.439224)