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The options-structure

It is possible to specify various options for the continuation run. The continuer stores the handle to the options in the variables cds.curve_options. A call to feval(cds.curve.options) must return a structure created with contset:

options = contset;

will initialize the structure. Options can then be set using

options = contset(options, optionname, optionvalue);

where optionname is an option from the following list.

InitStepsize
the initial stepsize (default: 0.01)
MinStepsize
the minimum stepsize to compute the next point on the curve (default: 10-5)
MaxStepsize
the maximum stepsize (default: 0.1)
MaxCorrIters
maximum number of correction iterations (default: 10)
MaxNewtonIters
maximum number of Newton-Raphson iterations before switching to Newton-Chords in the corrector iterations (default: 3)
MaxTestIters
maximum number of iterations to locate a zero of a testfunction (default: 10)
Increment
the increment to compute the derivatives numerically (default: 10-5)
FunTolerance
tolerance of function values: ||F(x)|| £ FunTolerance is the first convergence criterium of the Newton iteration (default: 10-6)
VarTolerance
tolerance of coordinates: ||dx|| £ VarTolerance is the second convergence criterium of the Newton iteration (default: 10-6)
TestTolerance
tolerance of test functions (default: 10-5)
Singularities
boolean indicating the presence of a singularity matrix (default: 0)
MaxNumPoints
maximum number of points on the curve (default: 300)
Backward
boolean indicating the direction of the continuation (sign of the initial tangent vector) v0 (default: 0)
CheckClosed
number of points indicating when to start to check if the curve is closed (0 = do not check) (default: 50)
Adapt
number of points after which to call the adapt-function while computing the curve (default: 1=adapt always)
IgnoreSingularity
vector containing indices of singularities which are to be ignored (default: empty)
Multipliers
boolean indicating the computation of the multipliers (default: 0)
Eigenvalues
boolean indicating the computation of the eigenvalues (default: 0)
Userfunctions
boolean indicating the presence of user functions (default: 0)
UserfunctionsInfo
is an array with structures containing information about the userfunctions. This structure has the following fields:
.label label of the userfunction
.name name of this particular userfunction
.state boolean indicating whether the userfunction has to be evaluated or not
PRC
variable indicating the computation of the phase response curve (default: empty)
dPRC
variable indicating the computation of the derivative of the phase response curve (default: empty)
Input
vector representing the input given to the system for the computation of the phase response curve (default: 0)

Options also contains some fields which are not set by the user but frozen or filled by calls to the curvefile, namely:

MoorePenrose
boolean indicating the use of the Moore-Penrose continuation as the Newton-like corrector procedure (default: 1)
SymDerivative
the highest order symbolic derivative which is present (default: 0)
SymDerivativeP
the highest order symbolic derivative with respect to the free parameter(s) which is present (default: 0)
Testfunctions
boolean indicating the presence of test functions (default: 0)
WorkSpace
boolean indicating to initialize and clean up user variable space (default: 0)
Locators
boolean vector indicating the user has provided his own locator code to locate zeroes of test functions. Otherwise the default locator will be used (default: empty)
ActiveParams
vector containing indices of the active parameter(s) (default: empty)