signal-diagram

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Description

signal-diagram implements functional reactive combinators that are used to build signal flow functions out of pure functions.

signal-diagram is inspired by functional reactive libraries such as Yampa and Opis.

signal-diagram provides a set of combinators to construct signal functions, which are functions operating on continuous time varying values. Every signal function has named input and output signals.

signal-diagram can generate executable code from a signal function definition in Scheme, Standard ML, and GNU Octave.

Pure signal functions and functional expressions

Basic combinators

IDENTITY fprocedure: Constructs a signal function that copies its input to the ouput.

PURE fprocedure: Constructs a signal function with no side effects.

RELATION r fprocedure: Defines the relation r within the signal function f.

UNION f gprocedure: Constructs a signal function whose input is the union of the inputs of signal functions f and g, and whose output is the union of the outputs of f and g.

SEQUENCE f gprocedure: Constructs a signal function that feeds its input to signal function f, then takes the resulting output and feeds it to g, along with any additional inputs required by g.

PIPE f gprocedure: Constructs a signal function that feeds its input to signal function f, then takes the resulting output and feeds it to g, without any any additional inputs.

SENSE ss fprocedure: Constructs a signal function that selects only the signals enumerated in ss from its input, and feeds the result to the signal function f.

ACTUATE ss fprocedure: Renames the outputs of f to the names specified in ss.

RTRANSITION f g ef eg sprocedure: Recurrent transition: constructs a signal function that behaves like f until the boolean signal specified by ef is true, when the signal function is switched to behave like g. If the boolean signal eg becomes true, the signal function is switched back to f. s is the name of the state variable that indicates the current state: if false, the state is f, otherwise the state is g.

TRANSITION f g ef eprocedure: Singularly occurring transition: constructs a signal function that behaves like f until the boolean signal specified by ef is true, when the signal function is switched to behave like g. s is the name of the state variable that indicates the current state: if false, the state is f, otherwise the state is g.

TRANSIENT f g efprocedure: Singularly occurring transition: constructs a signal function that behaves like f until the boolean signal specified by ef is true, when the signal function is switched to behave like g for (one invocation), and is then immediately switched back to f.

ON f efprocedure: Constructs a signal function that behaves like f only when the boolean signal specified by ef is true, otherwise copies the input to the output.

INTEGRAL i d fprocedure: One step numerical integration on the pure function f given independent variable i and dependent variable d.

INTEGRALH i d h fprocedure: One step numerical integration on the pure function f given independent variable i, dependent variable d, and step h.

Combinators for systems of equations

The following combinators are provided by library signal-diagram-dynamics:

ASSIGNprocedure

ODEprocedure

DAEprocedure

Code generation procedures

codegen/Octaveprocedure

codegen/schemeprocedure

codegen/MLprocedure

Requires

Version History

3.4 Added ON combinator
2.8 Adjustments to signal flow equations for actuate and union combinators
2.7 Added dyn-vector as a dependency in the meta file [thanks to Mario]
2.5 Bug fixes in relations handling in make-dae-system
2.3 Using make egg instead of setup-api for make macro
2.1 Added events procedure; better support for LSODE solver in Octave
2.0 Added state variable to the transition combinators
1.6 Improvements to the integrator interface
1.4 Exporting make-... procedures from signal-diagram-dynamics library
1.3 Moved RK library to flsim library
1.2 Install RK library files in Chicken shared directory
1.0 Initial release

License

 Copyright 2010-2014 Ivan Raikov


 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful, but
 WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 General Public License for more details.

 A full copy of the GPL license can be found at
 <http://www.gnu.org/licenses/>.

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