function [known] = mtt_component_eqn (fullname, port, causality, \
known, Cbg)
## function [known] = mtt_component_eqn (fullname, port, causality, known)
##
## Recursively finds the equations giving the signal of specified
## causality on the specified port of component named "name" within
## subsystem Name
## fullname: name of component and subsystem
## port: port number of component
## causality: effort or flow
## know_list: list of components already known
## Data structures.
## A signal is a row vector containing three numbers:
## Index -- a unique (within a subsystem) signed integer
## abs(index) is the unique bond number, sign is the direction.
## Causality -- 1 for effort, -1 for flow
## Port -- the port of the component to which it is connected.
##
[Name,name] = mtt_subname(fullname); # Split fullname
SD = "__"; # Subsystem delimiter
CD = "\n%%"; # Comment delimiter
arg_default = "1"; # Default aliased arg
cr_default = "lin"; # Default aliased arg
DEBUG = 0;
if DEBUG
disp("=======================================");
fullname, name, Name, port,causality,known
endif
eqn="## No equation -- something wrong"; # Default
if length(known)<2 # Invalid
known = " ";
endif
if length(Name)>0
cbg = mtt_cbg(Name); # Structure for this subsystem
if isfield (cbg, "ports")
## Combine ports with the other subsystems
for [component_structure, component] = cbg.ports
eval(sprintf("cbg.subsystems.%s=cbg.ports.%s;",component,component));
endfor
endif
endif
if length(name)>0 # Alias
##Alias arguments
eval(sprintf("ARG=cbg.subsystems.%s.arg;", name)); # Arguments
ARG = mtt_alias (Name,ARG,arg_default); # Alias them
eval(sprintf("cbg.subsystems.%s.arg=ARG;", name)); # and copy
## Alias CRs
eval(sprintf("CR=cbg.subsystems.%s.cr;", name)); # CRs
CR = mtt_alias (Name,CR,cr_default); # Alias them
eval(sprintf("cbg.subsystems.%s.cr=CR;", name)); # and copy
else # Call to a subsystem (represented by name="")
if !isfield(cbg,"portlist")
N_ports = 0;
else
[N_ports,M_ports] = size(cbg.portlist);
endif
if port>N_ports
error(sprintf("port (%i) > N_ports (%i)", port, N_ports));
else # Get name and find equation
name = deblank(cbg.portlist(port,:));
if DEBUG
disp("----> lower-level system")
endif
known = mtt_component_eqn (mtt_fullname(Name,name), 1, \
causality, known, cbg);
return
endif
endif
## Other causality representations
if strcmp(causality,"effort")
i_cause = 1;
othercausality = "flow";
index_cause = 1;
cause = "e";
elseif strcmp(causality,"flow")
i_cause = -1;
othercausality = "effort";
index_cause = 2;
cause = "f";
else
error(sprintf("mtt_component_eqn: causality %s invalid", causality));
endif
## A useful composite name
name_port_cause = sprintf("%s_%i_%s",name, port, cause);
full_name_port_cause = mtt_fullname(Name,name_port_cause);
## If value is known, don't do anything.
if findstr(sprintf(" %s ", full_name_port_cause), known)>0
eqn = sprintf("%s The %s signal on port %i of %s is known already", \
CD, causality, port, name);
return
else # Add to list
known = sprintf("%s %s", known, full_name_port_cause);
endif
## Component type
comp_type = eval(sprintf("cbg.subsystems.%s.type;", name));
if DEBUG
comp_type
endif
## Component cr
cr = eval(sprintf("cbg.subsystems.%s.cr;", name));
## Component arg
arg = eval(sprintf("cbg.subsystems.%s.arg;", name));
## To which bond(s) is the component connected?
connections = eval(sprintf("cbg.subsystems.%s.connections;", name));
bond_list = abs(connections); # Unsigned list
out_bond_number = bond_list(port); # The bond at the output of this component
direction = sign(connections); # Bond directions
directions = direction'*[1 1];
## List of system bonds
bonds = cbg.bonds;
## List of component bond causality (component-orientated causality)
comp_bonds = bonds(bond_list,:).*directions; # Component bonds
## What components are at the other ends of the in bonds?
## Effort
[in_e_bonds,in_e_components,in_e_ports,N_e] = mtt_component_inputs \
(name,comp_type,causality,"effort",comp_bonds,connections,cbg);
## Flow
[in_f_bonds,in_f_components,in_f_ports,N_f] = mtt_component_inputs \
(name,comp_type,causality,"flow",comp_bonds,connections,cbg);
##Composite values
N_ef = N_e + N_f;
in_ef_bonds = [in_e_bonds; in_f_bonds];
in_ef_components = [in_e_components; in_f_components];
in_ef_ports = [in_e_ports; in_f_ports];
in_causality = [ones(N_e,1); -ones(N_f,1)];
## Lists of signals relevant to this component
outsig = [out_bond_number i_cause port];
insigs = [in_ef_bonds in_causality in_ef_ports];
innames = in_ef_components;
if DEBUG
outsig
insigs
innames
endif
## Is the signal the output of a port?
is_port_output = 0; # Default
if isfield (cbg, "ports")
if isfield (cbg.ports,name)
is_port_output = (outsig(2)!=insigs(1,2));
endif
endif
if is_port_output
## Which port (number) is it?
[N_ports,M_ports] = size(cbg.portlist);
for i=1:N_ports
if strcmp(deblank(cbg.portlist(i,:)), name)
port_index = i;
break;
endif
endfor
## File containing data structure
NAME = mtt_subname(Name);
CBG = mtt_cbg(NAME);
## And to which component (at higher level) is it connected?
[new_Name,new_name] = mtt_subname(Name);
port_bond = eval(sprintf("CBG.subsystems.%s.connections(%i);", new_name, port_index));
[in_name, in_port, in_bond] = mtt_other_end (new_name,port_bond,CBG);
## Find its equation
if DEBUG
disp("----> higher level system")
endif
known = mtt_component_eqn (mtt_fullname(new_Name,in_name), \
in_port, causality, known, cbg);
LHS = Source_seqn ("external",Name);
RHS = varname(NAME, abs(in_bond), i_cause);
eqn = sprintf("%s%s%s := %s;", LHS, SD, name, RHS);
if !DEBUG
comment = sprintf("%s PORT", CD);
disp(sprintf("%s\n%s",comment, eqn));
endif
endif
## Handle special components
if strcmp(comp_type,"0")||strcmp(comp_type,"1") # Junctions
[eqn,insigs,innames] = junction_seqn (comp_type,Name, outsig, \
insigs, innames);
else # Everything else
if exist(sprintf("%s_cause", comp_type)) # Simple component
## Do the equations
[eqn,insigs,innames] = eval(sprintf("%s_seqn (Name, name, cr, \
arg, outsig, \
insigs, \
innames, is_port_output);", \
comp_type));
## Resolve CR
eqn = mtt_resolve_cr(eqn);
else # Compound component
new_NAME = Name;
new_Name = mtt_fullname(Name,name);
new_name = "";
## Get relevant data structure
Cbg = mtt_cbg(new_Name);
port_name = Cbg.portlist(port,:);
LHS = varname(Name, outsig(1,1), outsig(1,2));
RHS = Sensor_seqn ("external",new_Name);
eqn = sprintf("%s := %s%s%s;", LHS, RHS, SD, port_name);
if DEBUG
disp("----> same-level subsystem")
endif
[known] = mtt_component_eqn \
(mtt_fullname(new_Name,new_name), port, causality, known, cbg);
endif
endif
comment = \
sprintf("%s Equation for %s signal on port %i of %s (%s), subsystem %s.", \
CD, causality, port, name, comp_type, Name);
if DEBUG
disp(sprintf("%s\n%s",comment, eqn));
endif
is_external = mtt_is_external(comp_type,outsig, insigs, is_port_output);
if !is_external
## Find the corresponding input equations
[N_other,M_other] = size(insigs);
for i = 1:N_other
if insigs(i,2)==1
other_causality = "effort";
else
other_causality = "flow";
endif
other_port = insigs(i,3);
other_name = deblank(innames(i,:));
if DEBUG
disp("----> same-level component")
endif
[known] = mtt_component_eqn \
(mtt_fullname(Name,other_name), other_port, other_causality, \
known, cbg);
endfor
endif
## Write this signal
##comment_2 = sprintf("Connected to:%s", in_component_list);
if !DEBUG
disp(sprintf("%s\n%s",comment, eqn));
endif
endfunction