Model
¶
The central object in Myokit is the Model
. In most scenario’s, models
are created by parsing a file in
mmt syntax. Once parsed, a model can be
validated
to ensure its integrity. In models with
unsound semantics (for example a cyclical reference between variables) the
validate()
method will raise an IntegrityError
.
For models with a limited number of state variables, validation is fast. In
these cases, the validate()
method is run after parsing as an additional
check. For larger models, validation is costly and avoided until a simulation
is run or another analysis method is used.
Once created and validated, a model can be asked to
compute the solvable order of its equations
which can then be used by an exporter to generate runnable simulation or
analysis code.
A ModelComparison
class is available that can compare models
syntactically, while the step()
method can compare model output (either
to other models’ output or to stored reference files from external
implementations).
myokit.Model
¶

class
myokit.
Model
(name=None)¶ Represents an electrophysiological cell model, structured in components.
Components can be added to the model using
add_component()
. Access to a model’s component is provided through theget()
method andcomponents()
.Minimal dictionary support is provided: A component named “x” can be obtained from a model
m
usingm["x"]
. The number of components inm
is given bylen(m)
and the presence of “x” inm
can be tested usingif "x" in m:
.Variables stored inside components can be accessed using
get()
orvalues()
. Values defined through their derivative make up the model state and can be accessed usingstates()
. States have initial values accessible throughinitial_values()
.A model’s validity can be checked using
is_valid()
, which returns the latest validation status andvalidate()
, which (re)validates the model. Warnings can be obtained usingwarnings()
The optional constructor argument
name
can be used to set a meta property “name”.Metadata properties can be accessed via the property
meta
, for examplemodel.meta['key']= 'value'
.For consistency with components, variables, and expressions, models cannot be compared with
==
(which will only returnTrue
if both operands are the same object). Checking if models are the same in other senses can be done withis_similar()
. Models can be serialized withpickle
.
add_component
(name)¶ Adds a component with the given
name
to this model.This method resets the model’s validation status.
Returns the newly created
myokit.Component
object.

add_component_allow_renaming
(name)¶ Attempts to add a component with the given name to this model, but uses a different name if this causes any conflicts.
The new component’s name will be modified by appending _1, _2, etc. until the conflict is resolved.
This method can be used when symbolically manipulating a model in situations where the exact names are unimportant.
Returns the newly created
myokit.Component
object.

add_function
(name, arguments, template)¶ Adds a user function to this model.
Returns the newly created
myokit.UserFunction
object.

binding
(binding)¶ Returns the variable with the binding label
binding
. If no such variable is found,None
is returned.

bindings
()¶ Returns an iterator over all (binding label : variable) mappings in this model.

bindingx
(binding)¶ Returns the variable with the binding label
binding
, raising amyokit.IncompatibleModelError
if no such variable is found.See
Model.binding()
.

check_units
(mode=1)¶ Checks the units used in this model.
Models can specify units in two ways:
 By setting variable units. This is done using the
in
keyword inmmt
syntax or throughmyokit.Variable.set_unit()
. This specifies the unit that a variable’s value should be in.  By adding units to literals. This is done using square brackets in
mmt
syntax (for example5 [m] / 10 [s]
) or by adding a unit when creating a Number object, for examplemyokit.Number(2, myokit.units.mV)
.
When checking a model’s units, this method loops over all variables and performs two checks:
 The unit resulting from the variable’s RHS is evaluated. This
involves checking rules such as “in
x + y
,x
andy
must have the same units, or “inexp(x)
the units ofx
must bedimensionless
”. Amyokit.IncompatibleUnitExpression
will be raised if any inompatibilities are found.  The calculated unit is compared with the variable unit. An
IncompatibleUnitError
will be triggered if the two units don’t match.
Two unitchecking modes are available.
In strict mode (
mode=myokit.UNIT_STRICT
), all unspecified units in expressions are treated as “dimensionless”. For example, the expression5 * V
whereV
is in[mV]
will be treated as dimensionless times millivolt (or[1] * [mV]
in mmt syntax), resulting in the unit[mV]
. The expression5 + V
will be interpreted as dimensionless plus millivolt, and will raise an error. In strict mode, functions such assin
andexp
will check that their argument is dimensionless (sosin(3 [m])
is never allowed, only e.g.sin(3 [m] / 1 [m])
).In tolerant mode, unspecified units will be treated as whatever makes the expression work. So
? + [mV]
wil be interpreted as[mV] + [mV]
. In addition, functions that require dimensionless input in strict mode won’t perform this check in tolerant mode.A note about references:
In both modes, when a reference is encountered, for example when checking the expression
5 * y
, the system will look up the variable y’s unit, and will not look at y’s rhs. Consider the following buggy model:x = 5 [mV] # RHS unit, no variable unit y = 3 [A] + x # RHS unit, no variable unitWhen checking the expression
y = 3 + x
the variablex
will be treated as unspecified, because no variable unit is set forx
using thein
keyword. In strict mode, this will lead to an error when checkingx = 5 [mV]
becausex
is dimensionless while5 [mV]
has units[mV]
. In tolerant mode, no error will be raised. When tolerantly evaluatingy = 3[A] + x
it will be assumed thatx
is also in[A]
, because no variable unit is given that says otherwise (despite the RHS ofx
having unitsmV
). By setting variable units. This is done using the

clone
()¶ Returns a (deep) clone of this model.

code
(line_numbers=False)¶ Returns this model in
mmt
syntax.Line numbers can be added by setting
line_numbers=True
.

component_cycles
()¶ Finds cyclical references between components and returns them. For example, if
a.p
depends onb.q
whileb.x
depends ona.y
, a cyclea > b > a
will be returned.For a faster way to check if there are any interdependent components (without returning the exact cycles found), use
has_interdependent_components()
.

components
(sort=False)¶ Returns an iterator over this model’s component objects.

count_components
()¶ Returns the number of components in this model.

count_equations
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns the number of equations matching the given criteria. See
equations()
for an explanation of the arguments.

count_states
()¶ Returns the number of state variables in this model.

count_variables
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns the number of variables matching the given criteria. See
variables()
for an explanation of the arguments.

create_unique_names
()¶ Create a globally unique name for each Component and Variable.
Ideally, the global name equals the variable or component’s basic name. If a name is disputed the following strategy will be used:
 For variables, the parent name will be added as a prefix to all variables claiming the disputed name.
 If problems persist, a suffix
_i
will be added, wherei
is the first integer which doesn’t result in clashing names.
In addition, the method will avoid names listed using
reserve_unique_names()
and names starting with a prefix listed usingreserve_unique_prefix()
.

equations
(const=None, inter=None, state=None, bound=None, deep=False)¶ Creates and returns a filtered iterator over the equations of this object’s variables.
The returned values can be filtered using the following arguments:
const=TrueFalseNone
Set to
True
to return only constants’ equations.False
to exclude all constants and any other value to ignore this check.For a definition of “constant variable” see
variables()
.inter=TrueFalseNone
Set to
True
to return only intermediary variables’ equations,False
to exclude all intermediary variables and any other value to ignore this check.For a definition of “intermediary variable” see
variables()
.state=TrueFalseNone
 Set to
True
to return only state variables’ equations,False
to exclude all state variables and any other value to ignore this check. bound=TrueFalseNone
 Set to
True
to return only bound variables’ equations,False
to exclude all bound variables and any other value to ignore this check. deep=TrueFalse
(by default it’sFalse
) Set to
True
to include the equations of nested variables meeting all other criteria.

eval_state_derivatives
(state=None, inputs=None, precision=64, ignore_errors=False)¶ Deprecated alias of
evaluate_derivatives()
.

evaluate_derivatives
(state=None, inputs=None, precision=64, ignore_errors=False)¶ Evaluates and returns the values of all state variable derivatives. The values are returned in a list sorted in the same order as the state variables.
Arguments:
state=None
 If given, the state values given by
state
will be used as starting point. Herestate
can be any object accepted as input by :meth:map_to_state()
. inputs=None
 To set the values of external inputs, a dictionary mapping binding
labels to values can be passed in as
inputs
. precision
 To assist in finding the origins of numerical errors, the equations
can be evaluated using singleprecision floating point. To do this,
set
precision=myokit.SINGLE_PRECISION
. ignore_errors
 By default, the evaluation routine raises
myokit.NumericalError
exceptions for invalid operations. To returnNaN
instead, setignore_errors=True
.

expressions_for
(*variables)¶ Determines the expressions needed to evaluate one or more variables.
If state variables are included in the list, “evaluating” the variable is interpreted as evaluating its derivative.
Returns a tuple
(eqs, args)
whereeqs
is a list of Equation objects in solvable order containing the minimal set of equations needed to evaluate the givenvariable
andargs
is a list of the state variables and bound variables these expressions require as input.

format_state
(state=None, state2=None, precision=64)¶ Converts a sequence of floating point numbers to a string where each line has the format
<full_qualified_name> = <float_value>
.Arguments:
state=None
 The state to display. If no state is given this model’s (evaluated)
<initial_values()>initial values()
are used. state2=None
 An optional second state, to be shown next to
state
for comparison. precision=myokit.DOUBLE_PRECISION
 An optional precision argument to pass into
myokit.float.str()
when formatting the state values.

format_state_derivatives
(state=None, derivatives=None, precision=64)¶ Like
format_state()
but displays the derivatives along with each state’s value.Arguments:
state=None
 The state to show derivatives for. If no state is given this
model’s (evaluated)
<initial_values()>initial values()
are used. derivatives=None
 An optional list or other sequence of evaluated derivatives. If not
given, the values will be calculed from
state
usingeval_derivatives()
. precision=myokit.DOUBLE_PRECISION
 An optional precision argument to use when evaluating the state
derivatives, and to pass into
myokit.float.str()
when formatting the state values and derivatives.

format_warnings
()¶ Formats all warnings generated during the last call to
validate()
and returns a string containing the result.

get
(name, class_filter=None)¶ Searches for a component or variable with the given
qname
and returns it.To return only objects of a certain class, pass it in as
class_filter
.

get_function
(name, nargs)¶ Returns the user function with name
name
andnargs
arguments.

has_component
(name)¶ Returns
True
if this model has a component with the givenname
.

has_equations
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns True if there are any equations that can be returned by calling :meth:
equations
with the same arguments.

has_interdependent_components
()¶ Returns
True
if this model contains mutually dependent components. That is, if there exists any component A whose variables depend on variables from component B, while variables in component B depend on variables in component A.To see the variables causing the interdependence, use
component_cycles()
.

has_parse_info
()¶ Returns
True
if this model retains parsing information, so that methods such asitem_at_text_position()
andshow_line_of()
can be used.

has_variable
(name)¶ Returns True if the given name corresponds to a variable in this object. Accepts both single names
x
and qualified namesx.y
as input.This function performs the same search as
variable
, so in most cases it will be more efficient to callvariable()
in a trycatch block rather than checking for existence explicitly.

has_variables
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns True if there are any variables that can be returned by calling :meth:
variables
with the same arguments.

has_warnings
()¶ Returns
True
if this model has any warnings.

import_component
(external_component, new_name=None, var_map=None, allow_name_mapping=False, convert_units=False)¶ Imports one or multiple components from another model (the “source model”) into this one (the “target model”).
If variables in the
external_component
refer to variables from other components they will be mapped on to variables from this model by trying the following strategies (in order): Using the provided dict
var_map
, which maps variables in the source model to variables in this model.  By assuming variables with the same label/binding map onto each other.
 By assuming that variables with the same qualified names map onto
each other. This rule is only applied if
allow_name_mapping
is set toTrue
.
Arguments:
external_component
 A
myokit.Component
or a list ofcomponents
from another model. new_name
 An optional new name for the imported component or list of names if multiple components are provided.
var_map
 An optional dict mapping variables in the source model to variables from this model (with variables specified as objects or as fully qualified names).
allow_name_mapping
 Set this to
True
to allow mapping based on fully qualified names, e.g. a variablex.y
in the source model will be mapped to a variablex.y
in the target model. convert_units
 Set this to
True
to convert the units of any mapped variables, if required and possible.
If any variables cannot be mapped, a
myokit.VariableMappingError
will be raised. Amyokit.DuplicateNameError
will be raised if the component’s name ornew_name
clashes with an existing component name. If unit conversion is enabled and variables with incompattible units are mapped onto each other, a class:myokit.IncompatibleUnitsError will be raised. Using the provided dict

initial_values
(as_floats=False)¶ Returns a list of the model’s initial values.
By default, expressions are returned, but this can be changed to a list of floats by setting
as_floats=True
.

inits
()¶ Deprecated method: Returns an iterator over the
Equation
objects defining this model’s initial values.

is_similar
(other, check_unames=False)¶ Returns
True
if this model has the same code as theother
model.If
check_unames
is set toTrue
, the method also checks if the defined unique names and unique name prefixes are the same.

is_valid
()¶ Returns
True
if this model is valid,False
if it is invalid andNone
if the validation status has not been determined withvalidate()
.Valid models may still have one or more warnings.

item_at_text_position
(line, char)¶ Finds the component, variable, or expression at the position
(line, char)
, and returns a tuple(token, object)
with a parser token and the found object, orNone
if nothing is found.Both
line
andchar
should be given as integers. The first line is line 1, while the first character is char 0.

label
(label)¶ Returns the variable with the given
label
, orNone
if no such variable can be found.

labels
()¶ Returns an iterator over all (label : variable) mappings in this model.

labelx
(label)¶ Returns the variable with the label
label
, raising amyokit.IncompatibleModelError
if no such variable is found.See
Model.label()
.

load_state
(filename)¶ Deprecated method: Sets the model’s initial values using data from a file formatted in any style accepted by
myokit.map_to_state()
.

map_component_dependencies
(omit_states=True, omit_constants=False)¶ Scans all equations and creates a map of intercomponent dependencies.
The result is an ordered dictionary with the following structure:
{ comp1 : [dep1, dep2, dep3, ...], comp2 : [dep1, dep2, dep3, ...], ... }
where
comp1, comp2, ...
are Components anddep1, dep2, ...
are the components they depend upon.Only direct dependencies are listed: If
A
depends onB
andB
depends onC
then the returned value forA
is[B]
, not[B,C]
.By default, dependencies on state variables’ current values are omitted. This behavior can be changed by setting
omit_states
toFalse
.To omit all dependencies on constants, set
omit_constants
toTrue
.

map_component_io
(omit_states=False, omit_derivatives=False, omit_constants=False, rl_states=None)¶ Scans all equations and creates a list of input and output variables for each component.
Input variables are taken to be any foreign variables the component needs to perform its calculations, plus the current values of its own state variables if it needs them.
Output variables are taken to be any values calculated by this component but used outside it. This includes the derivatives of the state variables it calculates. State variables are never given as outputs, as it is assumed these are updated by an ODE solver.
The output can be customized using the following arguments:
omit_states
 Set to
True
to omit state values from the input lists. This can be useful in cases where the state is stored in a vector. omit_derivatives
 Set to
True
to omit derivatives from the input and output lists. This can be useful if derivatives are stored in a vector. omit_constants
 Set to
True
to omit constants from the input and output lists. This can be useful if constants are stored globally, e.g. as C macros. rl_states
 A map
{state_variable : {inf_variable, tau_variable}
can be passed in to enable mapping for RushLarsen schemes. In this case, all variables listed asinf
ortau_variable
will be included in component output lists, and the derivatives of eachstate_variable
in the mapping will only be added to the output list if there are other variables that depend on it.
The result is a tuple containing two
OrderedDict
objects, each of the following structure:{ comp1: [lhs1, lhs2, ...], comp2: [lhs1, lhs2, ...], ... }
The first dict contains the inputs to every component, the second dict contains every components output values. The values in the lists are :class:
LhsExpression
objects referring to either a variable or its derivative.

map_deep_dependencies
(collapse=False, omit_states=True, filter_encompassed=False)¶ Scans the list of equations stored in this model and creates a map relating each equation’s left hand side to a list of other
LhsExpressions
it depends on, either directly or through an intermediate variable.The method
map_shallow_dependencies()
performs a similar check, but only returns direct dependencies. This method expands the full dependency tree.The result is an
OrderedDict
with the following structure:{ lhs1 : [dep1, dep2, dep3, ...], ... }
where
lhs1
is aLhsExpression
anddep1
,dep2
anddep3
are theLhsExpression
objects it depends upon.If the system is not solvable: that is, if it contains cyclical references, a
myokit.IntegrityError
is raised.If the optional parameter
collapse
is set toTrue
nested variables will not be listed separatly. Instead, their dependencies will be added to the dependency lists of their parents.By default, dependencies on state variables’ current values are omitted. This behavior can be changed by setting
omit_states
toFalse
.In case of a dependency such as:
a = f(b) b = g(c)
the set returned for
a
will includeb
andc
. So whilea
here depends on bothb
andc
,b
’s sole dependency onc
meansa
can be calculated if justc
is known. To filter out the dependency onb
, setfilter_encompassed
toTrue
. Note that this will also filter out all dependencies on constants, since a constant’s dependencies (an empty set) can be said to be included in all other sets.

map_shallow_dependencies
(collapse=False, omit_states=True, omit_constants=False)¶ Scans the list of equations stored in this model and creates a map relating each equation’s left hand side to a list of other
LhsExpressions
it depends on directly.In contrast to the method
map_deep_dependencies()
, that performs a deep search for all nested dependencies, this method only returns direct dependencies. I.E. LhsExpressions named specifically in the equation’s right hand side.The result is an
OrderedDict
with the following structure:{ lhs1 : [dep1, dep2, dep3, ...], ... }
where
lhs1
is aLhsExpression
anddep1
,dep2
anddep3
are theLhsExpression
objects it depends upon.In special cases, the obtained result can differ from the mathematical concept of a dependency: if
x = 0 * y
the function will return a dependency ofx
ony
. Similarly, forx = if(cond, a, b)
the function will report a dependency ofx
oncond
,a
andb
.If the optional parameter
collapse
is set toTrue
nested variables will not be listed separatly. Instead, their dependencies will be added to the dependency lists of their parents.By default, dependencies on state variables’ current values are omitted. This behavior can be changed by setting
omit_states
toFalse
. Dependencies on constants are included by default, but this can be changed by settingomit_constants
toTrue
.

map_to_state
(state)¶ This utility function accepts a number of different input types and returns a list of floats in the same order as the model’s state variables.
The following types of input are meaningfully handled:
 A dictionary mapping state variable names or objects to floats
 A dictionary mapping state variable names or objects to lists. The
last value in every list will be used. This allows the dictionary
returned by
myokit.Simulation.run()
to be used directly.  A formatted string declaring each variable’s value using the syntax
component.var_name = 1.234
or simply containing a comma or space delimited list of floats.  A list of scalars. In this case, the list length will be checked and all values converted to float. No reordering takes place.

name
()¶ Returns the model meta property
name
, orNone
if it isn’t set.

remove_component
(component)¶ Removes a component from the model.
This will reset the model’s validation status.

remove_derivative_references
()¶ Scans this model’s RHS for any references to derivatives and removes them by introducing a new variable.
For example, given a (partial) model:
[ernie] dot(x) = (12  x) / 5 [bert] y = 1 + dot(x)
this method will update the model to:
[ernie] dot_x = (12  x) / 5 dot(x) = dot_x [bert] y = 1 + dot_x

reorder_state
(order)¶ Changes the order of this model’s state variables. The argument
order
must be a list of state variables or their qnames.This method does not affect the model’s validation status.

reserve_unique_name_prefix
(prefix, prepend)¶ Indicates a
prefix
that won’t be used in unique names (unames).When creating a unique name, any variable starting with
prefix
will be prepended with the stringprepend
.

reserve_unique_names
(*unames)¶ Reserves one or more names that won’t be used in unique names (unames).
This function can be used to add keywords to a model before exporting. After reserving one or more keywords, use
create_unique_names()
to reset the model’s unames.Adding new names does _not_ clear the previously reserved names.

resolve_interdependent_components
()¶ Checks if the model contains components that each depend on the other. If so, variables from these components will be moved to a new component called “remaining” until the issue is resolved.

save_state
(filename)¶ Deprecated method: Saves the model state to a file (as floats).

set_initial_values
(values)¶ Sets this model’s initial values.
The
values
must be specified as either a list of floats, expressions, and/or strings; or as a dict or string in a format accepted bymap_to_state()
.

set_name
(name=None)¶ Changes the value of the metaproperty “name”.

set_state
(state)¶ Deprecated method: use
set_initial_values()
instead.

set_value
(qname, value)¶ Changes a variable’s defining expression to the given number or
myokit.Expression
.For state variables, this updates the expression for their derivative. For all other variables, the expression for their value is updated.
This will reset the model’s validation status.

show_evaluation_of
(var)¶ Returns a string representing the evaluation of a single variable.
The variable’s equation and value are displayed, along with the value and formula of any nested variables and the values of all dependencies.

show_expressions_for
(var)¶ Returns a string containing the expressions needed to evaluate the given variable from the state variables.

show_line_of
(var, raw=False)¶ Returns a string containing the type of variable
var
is and the line it was defined on.If
raw
is set toTrue
the method returns an integer with the line number, orNone
if no line number information is known (i.e. if this model wasn’t created by parsing).

solvable_order
()¶ Returns all equations in a solvable order. The resulting output has the following structure:
OrderedDict { 'comp1' : EquationList([eq1, eq2, eq3, ...]), 'comp2' : EquationList([eq1, eq2, eq3, ...]), ..., '*remaining*' : EquationList([eq1, eq2, eq3]) }
The
OrderedDict
contains each component’s name as a key and maps it to a list of equations that can be solved for this component, stored in an :class:EquationList
object which extends thelist
type with a number of special iterators.The order of the components is such that the components with the fewest dependencies are listed first, in an effort to ensure as many equations as possible can be solved on a percomponent basis.
The final entry in the
OrderedDict
is a list of all remaining equations that could not be solved on a percomponent basis. For models that contain fully separable components (that is, if the model contains only components that depend on each other noncyclically) this list will be empty.

state
()¶ Deprecated method, use
initial_values(as_floats=True)
instead.

suggest_variable
(name)¶ Returns a tuple
(found, suggested, msg)
.If the requested variable is found, only the
found
part of the tuple is set. If not, the second and third argument are set. Heresuggested
will take the form of a suggested variable with a similar name, whilemsg
will be a suggested error message.

time
()¶ Returns this model’s time variable.
The time variable is identified by it’s binding to the external source “time”. For a valid model, this method always returns a unique variable. If no time variable has been declared
None
is returned.

time_unit
(mode=1)¶ Returns the units used by this model’s time variable.
If no time unit is set and
mode
ismyokit.UNIT_TOLERANT
(default), thenNone
is returned. Withmode
set tomyokit.UNIT_STRICT
the returned value in this case ismyokit.units.dimensionless
.

timex
()¶ Returns this model’s time variable, raising a
myokit.IncompatibleModelError
if no time variable is found.See
Model.time()
.

user_functions
()¶ Returns a dictionary mapping this model’s user function names to their
Expression
objects.

validate
(remove_unused_variables=False)¶ Validates this model and raises errors if any issues are found.
Small issues (e.g. unused variables) will generate warnings, which can be retrieved using
Model.warnings()
orModel.format_warnings()
. Any previously set warnings will be erased whenever validate() is run.If
remove_unused_variables
is set to True, any unused variables will be removed from this model during validation.

value
(qname)¶ Returns the value of a variable.

var
(name)¶ Searches for the given variable and returns it if found. Accepts both single names
x
and qualified namesx.y
as input.

variables
(const=None, inter=None, state=None, bound=None, deep=False, sort=False)¶ Creates and returns a filtered iterator over the contained variables.
The returned values can be filtered using the following arguments:
const=TrueFalseNone
Constants are defined as variables that do not depend on state variables or derivatives. In other words, any variable whose value can be determined before starting an ODE solving routine.
Set to
True
to return only constants,False
to exclude all constants and any other value to ignore this check.inter=TrueFalseNone
Intermediary variables are those variables that are not constant but are not part of the state. In other words, intermediary variables are the variables that need to be calculated at every step of an ODE solving routine before calculating the ODE derivatives and updating the state.
Set to
True
to return only intermediary variables,False
to exclude all intermediary variables and any other value to ignore this check.state=TrueFalseNone
 Set to True to return only state variables, False to exclude all state variables and any other value to ignore this check.
bound=TrueFalseNone
 Set to True to return only variables bound to an external value, False to exclude all bound variables and any other value to forgo this check.
deep=TrueFalse
(by default it’sFalse
) Set to True to return nested variables meeting all other criteria.
sort=TrueFalse
(by default it’sFalse
) Set to True to return the variables in a consistent order. (Note that this does _not_ mean alphabetical sorting of all variables, just that the order is consistent between calls!)

warnings
()¶ Returns a list containing the warnings generated in this model.

Helper classes and functions¶

myokit.
check_name
(name)¶ Tests if the given name is a valid myokit name and raises a
myokit.InvalidNameError
if it isn’t.

class
myokit.
ModelPart
(parent, name)¶ Base class for model parts.

code
()¶ Returns this object in
mmt
syntax.

is_ancestor
(obj)¶ Returns
True
if this object is an ancestor of the givenModelPart`
object
.

model
()¶ Returns the
myokit.Model
this object belongs to (if set).

name
()¶ Returns this object’s name.

parent
(kind=None)¶ Returns this object’s parent.
If the optional variable
kind
is set, the method will scan until an instance of the requested type is found.

qname
(hide=None)¶ Returns this object’s fully qualified name. That is, an object named
y
with a parent namedx
will return the stringx.y
. Ify
has a childz
its qname will bex.y.z
.If the optional argument
hide
is set to this object’s parent the parent qualifier will be omitted.

uname
()¶ Returns a globally unique name for this object.


class
myokit.
ObjectWithMetaData
¶ Base class for objects with meta data.
Metadata properties are all stored in a dict and should be string:string mappings.

class
myokit.
MetaDataContainer
¶ Dictionary that stores string metadata.
Each key must be a valid Myokit name (so start with at least one letter, and contain only letters, numbers, and underscores), or a series of valid Myokit names separated by colons (
:
). Values can be any string.A MetaDataContainer can be cloned using
clone = MetaDataContainer(original)
.

class
myokit.
VarOwner
(parent, name)¶ Represents a holder of Variables
Minimal dictionary support is provided: A variable named “x” can be obtained from an owner
m
usingm["x"]
. The number of variables inm
is given bylen(m)
and the presence of “x” inm
can be tested usingif "x" in m:
.
add_variable
(name)¶ Adds a child variable with the given name to this
VarOwner
.Returns the newly created
myokit.Variable
object.

add_variable_allow_renaming
(name)¶ Attempts to add a child variable with the given name to this
VarOwner
, but uses a different name if this causes any conflicts.The new variable’s name will be modified by appending _1, _2, etc. until the conflict is resolved.
This method can be used when symbolically manipulating a model in situations where the exact names are unimportant.
Returns the newly created
myokit.Variable
object.

can_add_variable
(name, variable_whitelist=None)¶ Returns
True
if a variable can be added to thisVarOwner
under the givenname
.This method is automatically called by
add_variable()
and move_variable(), there is no need to call it before using these methods.To ignore clashes with known variables, a list
variable_whitelist
can be passed in.

get
(name, class_filter=None)¶ Searches for a variable with the given
qname
and returns it.To return only objects of a certain class, pass it in as
class_filter
.The qnames are specified relative to the
VarOwner
. For example, in a model with a componentina
and a variableina.h
we expect the following results>>> import myokit >>> m = myokit.load_model('example') >>> c = m.get('ina') # Retrieves the component <ina> >>> h = c.get('h') # Retrieves the variable <ina.h> >>> x = c.get('ina.h') # Searches for <ina.ina.h>: KeyError! Traceback (most recent call last): File "<stdin>", line 1, in <module> KeyError: 'ina'

move_variable
(variable, new_parent, new_name=None)¶ Moves the given variable to another
VarOwner
new_parent
. In addition, this method can be used to rename variables (either with or without moving them).

remove_variable
(variable, recursive=False)¶ Removes the given variable from this
VarOwner
and from the model.If
recursive
isTrue
, any child variables will be deleted as well.A
myokit.IntegrityError
will be raised if


class
myokit.
VarProvider
¶ Abstract class
This class provides an iterator over variables and equations for any object that can provide access to an iterator over its variables.

count_equations
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns the number of equations matching the given criteria. See
equations()
for an explanation of the arguments.

count_variables
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns the number of variables matching the given criteria. See
variables()
for an explanation of the arguments.

equations
(const=None, inter=None, state=None, bound=None, deep=False)¶ Creates and returns a filtered iterator over the equations of this object’s variables.
The returned values can be filtered using the following arguments:
const=TrueFalseNone
Set to
True
to return only constants’ equations.False
to exclude all constants and any other value to ignore this check.For a definition of “constant variable” see
variables()
.inter=TrueFalseNone
Set to
True
to return only intermediary variables’ equations,False
to exclude all intermediary variables and any other value to ignore this check.For a definition of “intermediary variable” see
variables()
.state=TrueFalseNone
 Set to
True
to return only state variables’ equations,False
to exclude all state variables and any other value to ignore this check. bound=TrueFalseNone
 Set to
True
to return only bound variables’ equations,False
to exclude all bound variables and any other value to ignore this check. deep=TrueFalse
(by default it’sFalse
) Set to
True
to include the equations of nested variables meeting all other criteria.

has_equations
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns True if there are any equations that can be returned by calling :meth:
equations
with the same arguments.

has_variable
(name)¶ Returns True if the given name corresponds to a variable in this object. Accepts both single names
x
and qualified namesx.y
as input.This function performs the same search as
variable
, so in most cases it will be more efficient to callvariable()
in a trycatch block rather than checking for existence explicitly.

has_variables
(const=None, inter=None, state=None, bound=None, deep=False)¶ Returns True if there are any variables that can be returned by calling :meth:
variables
with the same arguments.

var
(name)¶ Searches for the given variable and returns it if found. Accepts both single names
x
and qualified namesx.y
as input.

variables
(const=None, inter=None, state=None, bound=None, deep=False, sort=False)¶ Creates and returns a filtered iterator over the contained variables.
The returned values can be filtered using the following arguments:
const=TrueFalseNone
Constants are defined as variables that do not depend on state variables or derivatives. In other words, any variable whose value can be determined before starting an ODE solving routine.
Set to
True
to return only constants,False
to exclude all constants and any other value to ignore this check.inter=TrueFalseNone
Intermediary variables are those variables that are not constant but are not part of the state. In other words, intermediary variables are the variables that need to be calculated at every step of an ODE solving routine before calculating the ODE derivatives and updating the state.
Set to
True
to return only intermediary variables,False
to exclude all intermediary variables and any other value to ignore this check.state=TrueFalseNone
 Set to True to return only state variables, False to exclude all state variables and any other value to ignore this check.
bound=TrueFalseNone
 Set to True to return only variables bound to an external value, False to exclude all bound variables and any other value to forgo this check.
deep=TrueFalse
(by default it’sFalse
) Set to True to return nested variables meeting all other criteria.
sort=TrueFalse
(by default it’sFalse
) Set to True to return the variables in a consistent order. (Note that this does _not_ mean alphabetical sorting of all variables, just that the order is consistent between calls!)

Model comparison¶

class
myokit.
ModelComparison
(model1, model2, live=False)¶ Compares two models.
The resulting diff text can be iterated over:
for line in ModelComparison(m1, m2): print(line)
Differences can be printed directly to
stdout
by settinglive=True
.
equal
()¶ Returns
True
if the two models were equal.

text
()¶ Returns the full difference text.


myokit.
step
(model, initial=None, reference=None, ignore_errors=False)¶ Evaluates the state derivatives in a model and compares the results with a list of reference values, if given.
The
model
should be given as a validmyokit.Model
. The state values to start from can be given asinitial
, which should be any item that can be converted to a valid state usingmodel.map_to_state
.The values can be compared to reference output given as a list
reference
. Alternatively, ifreference
is a model the two models’ outputs will be compared.By default, the evaluation routine checks for numerical errors (dividebyzeros, invalid operations and overflows). To run an evaluation without error checking, set
ignore_errors=True
.Returns a string indicating the results.