Request Rate not reaching desired level.

Hi Andy!

The Ramp component is old and it's our goal to replace it with the Ramp Sequence component as soon as we're certain that nobody will miss the Ramp component.

The Ramp component has been improved since beta 2 to be much better when it comes to the things that you point out. If you would like to give it a go, please use this code:

/**
 * Ramps up, holds steady and then ramps down.
 *
 * @id com.eviware.MultiRamp
 * @name Ramp Sequence
 * @category generators
 * @help http://loadui.org/Generators/ramp-sequence.html
 * @nonBlocking true
 */

import java.util.concurrent.TimeUnit

createProperty( 'rampLength', Long, 10 ) { calculateAcceleration() }
createProperty( 'peakRate', Long, 10 ) { calculateAcceleration() }
createProperty( 'peakLength', Long, 10 )
createProperty( 'peakRateUnit', String, 'sec' ) { calculateAcceleration(); redraw() }

future = null
cancellingFuture = null
startTime = 0
triggersSent = 0
calculateAcceleration()

onAction( 'START' ) {
 calculateAcceleration()
 startTime = currentTime()
 hasPeaked = false
 scheduleNext( startTime )
 triggersSent = 0
}

onAction( 'STOP' ) {
 future?.cancel( true )
 cancellingFuture?.cancel( true )
 startTime = null
}

scheduleNext = { wakeTime ->
 def t0 = getT0()
 
// println( "Too late with: " + wakeTime - getT0() )
// println( "Missed triggers: " + a*(t0**2 - wakeTime**2)/2 )
 
 if( t0 >= rampLength.value && !hasPeaked ) {
  hasPeaked = true
  triggersSent = 0
  def delay = 1000000/peakRate.value
  if( peakRateUnit.value == 'min' )
   delay = 1000000/(peakRate.value/60)
  future = scheduleAtFixedRate( { trigger() }, delay, delay, TimeUnit.MICROSECONDS )
  cancellingFuture = schedule( {
   future?.cancel( true )
   a = a*-1
   scheduleNext( rampLength.value )
  }, peakLength.value, TimeUnit.SECONDS )
 } else if( t0 >= 0 ) {
  def triggersThatShouldHaveBeenSent = 0
  if( hasPeaked ) {
   triggersThatShouldHaveBeenSent = Math.floor( a*t0**2/2 - a*rampLength.value**2/2 )
  }
  else
   triggersThatShouldHaveBeenSent = Math.floor( a*t0**2/2 )
  
  while( triggersSent < triggersThatShouldHaveBeenSent ) {
   trigger()
   triggersSent++
  }
 
  t1 = Math.sqrt( 2/a + t0**2 )
  future?.cancel( true )
  def diff = Math.abs( t1 - getT0() )
  if( !Double.isNaN( diff ) ) {
   future = schedule( {
     trigger()
     triggersSent++
     scheduleNext( t1 )
    }, ( diff*1000000) as long, TimeUnit.MICROSECONDS )
  }
 }
}

def getT0() {
 if( !startTime ) return 0
 relativeTime = currentTime() - startTime
 if( relativeTime >= rampLength.value + peakLength.value )
  return startTime + rampLength.value*2 + peakLength.value - currentTime()
 if( relativeTime >= rampLength.value )
  return rampLength.value
 return relativeTime
}

def redraw() {
 layout {
  property( property:rampLength, label:'Ramp Duration\n(sec)', min:1 )
  property( property:peakLength, label:'Peak Duration\n(sec)', min:0 )
  separator( vertical:true )
  property( property:peakRate, label:'Peak Rate\n(VU/' + peakRateUnit.value + ')', min:1 )
  property( property:peakRateUnit, label:'Unit', options:['sec','min'] )
  separator( vertical:true )
  box( widget:'display' ) {
   node( label:'Rate', content: { if( getT0() > 0 ) String.format( '%7.1f', peakRateUnit.value == 'sec' ? a*getT0() : a*getT0()*60 ) else 0 }, constraints:'w 45!' )
  }
 }
}
redraw()

compactLayout {
 box( widget:'display' ) {
  node( label:'Rate', content: { if( getT0() > 0 ) String.format( '%7.1f', peakRateUnit.value == 'sec' ? a*getT0() : a*getT0()*60 ) else 0 }, constraints:'w 45!' )
 }
}

def currentTime() {
 System.currentTimeMillis() / 1000
}

def calculateAcceleration() {
 if( peakRateUnit.value == 'sec' )
  a = peakRate.value / rampLength.value
 else
  a = (peakRate.value/60) / rampLength.value
}

Regards!

Henrik
SmartBear Software