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This was a seperate repository in CVS and so it missed the conversion.
benchmarks/
As above.
57 lines
1.9 KiB
Haskell
57 lines
1.9 KiB
Haskell
--
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-- Patricia Fasel
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-- Los Alamos National Laboratory
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-- 1990 August
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--
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module PushParticle (pushParticle) where
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import PicType
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import Consts
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import Data.Array--1.3
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-- Phase IV: Particle push
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-- Each particle has an initial velocity determined by its motion during the
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-- previous timestep and is accelerated by the field induced by the
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-- collection of particles
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--
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-- Compute the acceleration of each particle
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-- Find the maximum acceleration in x and y directions
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-- Determine a safe delta t, such that no particle will move a
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-- distance greater than the cell
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-- Compute new position and velocity of each particle
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pushParticle :: ParticleHeap -> Electric -> Value -> Value -> Value -> (Value, Value, ParticleHeap)
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pushParticle ([], []) xyElec dt maxAcc maxVel = (maxAcc, maxVel, ([], []))
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pushParticle (((xPos,yPos):xyPos), ((xVel,yVel):xyVel))
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(xElec, yElec) dt maxAcc maxVel =
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(maxAcc'', maxVel'',
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(((xPos',yPos'):xyPos'), ((xVel',yVel'):xyVel')))
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where
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i = truncate xPos
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j = truncate yPos
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i1 = (i+1) `rem` nCell
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j1 = (j+1) `rem` nCell
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dx = xPos - fromIntegral i
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dy = yPos - fromIntegral j
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xAcc = (charge/mass) * (xElec!(i,j)*(1-dy) + xElec!(i,j1)*dy)
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yAcc = (charge/mass) * (yElec!(i,j)*(1-dx) + yElec!(i1,j)*dx)
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xTV = xAcc*dt + xVel
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yTV = yAcc*dt + yVel
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xT = xTV*dt + xPos
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yT = yTV*dt + yPos
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maxAcc' = max maxAcc (max (abs xAcc) (abs yAcc))
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maxVel' = max maxVel (max (abs xTV) (abs yTV))
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(xVel',yVel') = (xTV, yTV)
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xPos' = if (xT >= fromIntegral nCell)
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then xT - fromIntegral nCell
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else if (xT < 0.0)
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then xT + fromIntegral nCell
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else xT
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yPos' = if (yT >= fromIntegral nCell)
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then yT - fromIntegral nCell
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else if (yT < 0.0)
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then yT + fromIntegral nCell
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else yT
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(maxAcc'', maxVel'', (xyPos', xyVel')) =
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pushParticle (xyPos, xyVel) (xElec, yElec) dt maxAcc' maxVel'
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