Inspiration Pad Pro 3.0 Logarithm

Comments

• llargando

  April 2016

  Dang it, until you mentioned natural logs, I didn't even know I wanted them!
  
  The following code isn't pretty, but it's correct within several decimal places:
  

  table: test
  ln(1) = [@NaturalLog with 1]\n&
  ln(2) = [@NaturalLog with 2]\n&
  ln(3) = [@NaturalLog with 3]\n&
  ln(4) = [@NaturalLog with 4]\n&
  ln(5) = [@NaturalLog with 5]\n&
  ln(6) = [@NaturalLog with 6]\n&
  ln(7) = [@NaturalLog with 7]\n&
  ln(8) = [@NaturalLog with 8]\n&
  ln(9) = [@NaturalLog with 9]\n&
  ln(10) = [@NaturalLog with 10]\n&
  ln(20) = [@NaturalLog with 20]\n&
  ln(30) = [@NaturalLog with 30]\n&
  ln(40) = [@NaturalLog with 40]\n&
  ln(50) = [@NaturalLog with 50]\n&
  ln(60) = [@NaturalLog with 60]\n&
  ln(70) = [@NaturalLog with 70]\n&
  ln(80) = [@NaturalLog with 80]\n&
  ln(90) = [@NaturalLog with 90]\n&
  ln(100) = [@NaturalLog with 100]\n&
  ln(200) = [@NaturalLog with 200]\n&
  ln(300) = [@NaturalLog with 300]\n&
  ln(400) = [@NaturalLog with 400]\n&
  ln(500) = [@NaturalLog with 500]\n&
  ln(600) = [@NaturalLog with 600]\n&
  ln(700) = [@NaturalLog with 700]\n&
  ln(800) = [@NaturalLog with 800]\n&
  ln(900) = [@NaturalLog with 900]\n&
  ln(1000) = [@NaturalLog with 1000]
  
  table: NaturalLog
  {e==2.718281828459}&
  {tgt=={$1}}&
  {prevLow==0}&
  {prevHigh==-1}&
  {exp==10}&
  {newTry==e^exp}&
  [@40 subNaturalLog]&
  {round(exp*1000000)/1000000}
  
  table: subNaturalLog
  {diff=={(newTry-tgt)*1000000000}}&
  [when not]{abs(diff)}<0.001[do][#{diff/abs(diff)+2} subNaturalLogTryAgain][end]&
  {newTry==e^exp}
  
  table: subNaturalLogTryAgain
  1:{prevLow==exp}[when]{prevHigh}<0[do]{exp==exp+1}[else]{exp==exp+((prevHigh-exp)/2)}[end]
  2:{prevHigh==exp}{exp==exp+((prevLow-exp)/2)}
  

  Hope it's useful!
• TTacitusMagnificatus

  April 2016

  Thank you very much largando!
  
  Will let you know as soon as I have tested it.