spacing

linspace.js

// return an array containing (len) linearly-spaced values from (min) to (max)

function linspace(from, to, len){
  var arr = new Array(len)
    , step = ( to - from ) / ( len - 1 )
    , i = 0
  for ( ; i < len; ++i )
    arr[i] = from + ( i * step )
  return arr
}

linspace(0, 10, 3)   // [0, 5, 10]
linspace(20, 40, 5)  // [20, 25, 30, 35, 40]

logspace.js

// return an array containing (len) logarithmically-spaced values from (min) to (max)
//
// useful for frequency response graphs

function logspace(from, to, len){
  var err = 'from must be greater than zero'
    , base = Math.pow( to / from, 1 / len )
    , arr = new Array(len)
    , i = 1
  if ( isNaN(base) ) throw new TypeError(err)
  for ( ; i <= len; ++i )
    arr[i - 1] = from * Math.pow(base, i)
  return arr
}