Overview
Comment:In implicit approach, set derivatives to zero (when switch is off)
before update. This seems to stop numerical leakage though non-return
switches.
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SHA3-256: c73a1c2553575e5eb007102a9e4791b15050a308d99fa077dc2778f46e7bad31
User & Date: gawthrop@users.sourceforge.net on 1999-03-30 21:39:25
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Context
1999-04-02
02:13:58
Back to RCS check-in: 6657031eb6 user: gawthrop@users.sourceforge.net tags: origin/master, trunk
1999-03-30
21:39:25
In implicit approach, set derivatives to zero (when switch is off)
before update. This seems to stop numerical leakage though non-return
switches. check-in: c73a1c2553 user: gawthrop@users.sourceforge.net tags: origin/master, trunk
1999-03-28
21:29:40
Initial revision check-in: 09d6bbc48c user: gawthrop@users.sourceforge.net tags: origin/master, trunk
Changes
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Modified mttroot/mtt/bin/trans/make_ode2odes from [c4ac8a5bd5] to [de3020d4fa]. 

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#! /bin/sh

     ###################################### 
     ##### Model Transformation Tools #####
     ######################################

###############################################################
## Version control history
###############################################################
## $Id$
## $Log$
## Revision 1.18  1999/03/15 01:17:07  peterg
## Removed some spurious debugging code
##
## Revision 1.17  1999/03/15 01:09:15  peterg
## Fixed bugs when Nx=0 (no state)
##
## Revision 1.16  1999/03/06 02:28:38  peterg
## Rearranged evaluation to: state - input - output - write
##
## Revision 1.15  1999/03/06 02:19:43  peterg
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$1_simpar;			# Read in simulation parameters
$1_numpar;			# Read in parameters
MTTilast = round(mttlast/mttdt); # Total number of steps

#Initialise
MTTt = 0.0;
[MTTu]  = zero_vector($Nu);	# Zero the input
if $Nx>0
#if $Nx>0
  [MTTx] = $1_state;	        # Read in initial state
else
  MTTx = 0;			# Dummy value
endif;
#else
#  MTTx = 0;			# Dummy value
#endif;

[MTTy] = $1_odeo(MTTx,MTTu,MTTt); # Evaluate initial output
[MTTu] = $1_input(MTTt,MTTx,MTTy);	# Evaluate initial input
mtt_write(MTTt,MTTx,MTTy,$Nx,$Ny); # And write them

[mttAA]  = zero_matrix($Nx);	# Zero the A matrix
[mttAAx] = zero_vector($Nx);	# Zero the AAx vector

if $Nx>0
  [MTTx] = $1_switch(MTTx);       # Switches
endif;

if mttmethod==1			# Euler
  MTTddt = mttdt/mttstepfactor; # The small sample interval
endif;


for MTTit = 1:MTTilast		#Integration loop

  if $Nx>0			# Don't if no states
  if $Nx>0			# Dont if no states
    if mttmethod==1		# Euler
      for MTTjt = 1:mttstepfactor
	[MTTdx] = $1_ode(MTTx,MTTu,MTTt); # State derivative
	[MTTx] = mtt_euler(MTTx,MTTdx,MTTddt,$Nx); # Euler update
	[MTTx] = $1_switch(MTTx);	# Switches
	MTTt = MTTt + MTTddt;
      endfor;
    endif;
    if mttmethod==2		# Implicit 
      [MTTdx] = $1_ode(MTTx,MTTu,MTTt); # State derivative
      [MTTdx] = $1_switch(MTTx);	# Set derivs to zero if states to zero
      [mttAA,mttAAx] = $1_smx(MTTx,MTTu,mttdt);	# (I-Adt) and (I-Adt)x
      [mttAA] = $1_switcha(mttAA,MTTx);	# Switches
      [MTTx] = mtt_implicit(MTTx,MTTdx,mttAA,mttAAx,mttdt,$Nx); # Implicit update
      [MTTx] = $1_switch(MTTx);	# Switches
      MTTt = MTTt + mttdt;
    endif;
    else
      MTTt = MTTt + mttdt;
  endif;			# $Nx>0

  [MTTy] = $1_odeo(MTTx,MTTu,MTTt);     # Output
︙

MTT: Model Transformation Tools
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