Exercise 15 Index   <<   >>


 

Let x and y be vectors of floating point numbers. Compare the times for x⍳y and x{⎕ct←0 ⋄ ⍺⍳⍵}y . Compare their results.























   I0←{⎕ct←0 ⋄ ⍺⍳⍵}

   x ← ?1e6⍴0
   y ← ?1e6⍴0
   cmpx 'x⍳y' 'x I0 y'
  x⍳y    → 2.05e¯1 |   0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕
  x I0 y → 1.22e¯1 | -41% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕

   x ← 0.1 , ?1e6⍴9e5
   y ← 100 × 100 ÷⍨ x
   cmpx 'x⍳y' 'x{⎕ct←0 ⋄ ⍺⍳⍵}y'
  x⍳y    → 1.79e¯1 |   0% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕
* x I0 y → 1.11e¯1 | -39% ⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕⎕