Block type: assignment
| Parameter | Description |
|---|---|
| input ports | 2 input port(s) declared. |
| Parameter | Description |
|---|---|
| output ports | 1 output port(s) declared. |
Writes elements into a signal: out = base with out[Indices] = values.
| Module | nflow_blocks |
| Library | Utility |
| Type | assignment |
| Label | Assignment |
Description
Writes elements into a signal (Assignment). Port 0 is the base signal; its width sets the output width; port 1 carries the replacement values. Indices (1-based) selects which base elements are overwritten by the successive values: out = base, then out[Indices[k]] = values[k]. Elements not listed pass through unchanged. Simulation-only (vector-shape routing, like reshape / selector): no scalar code-generation path.
Ports
Input(s)
| Port | Role | Side | Position |
|---|---|---|---|
| Port_1 | Numeric signal read by the block. | left | x=0, y=20 |
| Port_2 | Numeric signal read by the block. | left | x=0, y=40 |
Output(s)
| Port | Role | Side | Position |
|---|---|---|---|
| Port_1 | Numeric signal produced by the block. | right | x=90, y=30 |
Parameters
| Parameter | Default value |
|---|---|
Indices |
[1] |
Block Characteristics
| Block type | assignment |
| Family | Utility |
| Rendered size | 90 x 60 |
| Phases | ALGEBRAIC |
| Internal state or history | no |
| Signal data type | double numeric values |
Algorithms
Extended Capabilities
Native runtime only (this block is not code-generated).
Code generation: supported for C and Rust.
Implementation Sources
modules/nflow_blocks/libraries/utility/library.json{
"id": "builtin.utility",
"title": "Utility",
"version": "1.0.0",
"format": "nflow-2",
"metadata": {
"author": "Allan CORNET",
"created": "2026-03-21",
"tool": "Nelson nflow"
},
"comment": "Utility blocks such as switches, comments, and subsystems",
"license": "LGPL-3.0",
"builtin": true,
"blocks": [
{
"type": "comment",
"label": "Comment",
"icon": "comment.svg",
"phases": [],
"width": 220,
"height": 120,
"inputs": [],
"outputs": [],
"defaultParams": {
"CommentText": "",
"ShowBorder": true
},
"render": {
"type": "comment",
"bodyClass": "block-body"
}
},
{
"type": "switch",
"label": "Switch",
"icon": "switch.svg",
"phases": [
"ALGEBRAIC"
],
"width": 80,
"height": 80,
"inputs": [
{
"x": 0,
"y": 0,
"side": "left"
},
{
"x": 0,
"y": 40,
"side": "left"
},
{
"x": 0,
"y": 80,
"side": "left"
}
],
"outputs": [
{
"x": 80,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"Criteria": "ge",
"Threshold": 0
},
"render": {
"type": "math",
"bodyClass": "block-body",
"mathGroupClass": "switch-math"
}
},
{
"type": "multiportSwitch",
"label": "Multiport Switch",
"icon": "multiportSwitch.svg",
"phases": [
"ALGEBRAIC"
],
"width": 40,
"height": 80,
"inputs": [
{
"x": 20,
"y": 0,
"side": "top"
},
{
"x": 0,
"y": 20,
"side": "left"
},
{
"x": 0,
"y": 40,
"side": "left"
},
{
"x": 0,
"y": 60,
"side": "left"
}
],
"outputs": [
{
"x": 40,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"DataPortCount": 3
},
"render": {
"type": "image",
"src": "exports/multiportSwitch.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 40,
"height": 90
}
},
{
"type": "toggleSwitch",
"label": "Toggle Switch",
"icon": "toggleSwitch.svg",
"phases": [
"OUTPUT"
],
"width": 80,
"height": 50,
"inputs": [],
"outputs": [
{
"x": 80,
"y": 25,
"side": "right"
}
],
"defaultParams": {
"State": 0,
"OnLabel": "ON",
"OffLabel": "OFF",
"OnValue": 1,
"OffValue": 0
},
"render": {
"type": "toggle"
}
},
{
"type": "subsystem",
"icon": "subsystem.svg",
"label": "Subsystem",
"phases": [
"INIT",
"OUTPUT",
"ALGEBRAIC",
"UPDATE"
],
"width": 120,
"height": 80,
"inputs": [
{
"x": 0,
"y": 40,
"side": "left"
}
],
"outputs": [
{
"x": 120,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"name": "Subsystem",
"externalInputs": [],
"externalOutputs": [],
"subsystem": null
},
"render": {
"type": "math",
"bodyClass": "block-body",
"mathGroupClass": "subsystem-math",
"formula": "\\mathsf{Sub}"
}
},
{
"type": "mux",
"label": "Mux",
"icon": "mux.svg",
"phases": [
"OUTPUT"
],
"width": 8,
"height": 40,
"inputs": [
{
"x": 0,
"y": 10,
"side": "left"
},
{
"x": 0,
"y": 30,
"side": "left"
}
],
"outputs": [
{
"x": 8,
"y": 20,
"side": "right"
}
],
"defaultParams": {
"Inputs": 2
}
},
{
"type": "demux",
"label": "Demux",
"icon": "demux.svg",
"phases": [
"OUTPUT"
],
"width": 8,
"height": 40,
"inputs": [
{
"x": 0,
"y": 20,
"side": "left"
}
],
"outputs": [
{
"x": 8,
"y": 10,
"side": "right"
},
{
"x": 8,
"y": 30,
"side": "right"
}
],
"defaultParams": {
"Outputs": 2
}
},
{
"type": "convert",
"label": "Convert",
"icon": "convert.svg",
"phases": [
"ALGEBRAIC"
],
"width": 90,
"height": 50,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
}
],
"outputs": [
{
"x": 90,
"y": 25,
"side": "right"
}
],
"defaultParams": {
"OutDataType": "double",
"SaturateOnOverflow": true,
"Rounding": "nearest"
}
},
{
"type": "initialCondition",
"label": "IC",
"icon": "initialCondition.svg",
"phases": [
"ALGEBRAIC"
],
"width": 90,
"height": 50,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
}
],
"outputs": [
{
"x": 90,
"y": 25,
"side": "right"
}
],
"defaultParams": {
"InitialValue": 0
}
},
{
"type": "dataStoreMemory",
"label": "Data Store Memory",
"icon": "dataStoreMemory.svg",
"phases": [
"INIT"
],
"width": 70,
"height": 60,
"inputs": [],
"outputs": [],
"defaultParams": {
"DataStoreName": "A",
"InitialValue": 0
},
"render": {
"type": "image",
"src": "exports/dataStoreMemory.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 70,
"height": 60
}
},
{
"type": "dataStoreWrite",
"label": "Data Store Write",
"icon": "dataStoreWrite.svg",
"phases": [
"INIT",
"UPDATE"
],
"width": 70,
"height": 60,
"inputs": [
{
"x": 0,
"y": 30,
"side": "left"
}
],
"outputs": [],
"defaultParams": {
"DataStoreName": "A"
},
"render": {
"type": "image",
"src": "exports/dataStoreWrite.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 70,
"height": 60
}
},
{
"type": "dataStoreRead",
"label": "Data Store Read",
"icon": "dataStoreRead.svg",
"phases": [
"OUTPUT"
],
"width": 70,
"height": 60,
"inputs": [],
"outputs": [
{
"x": 70,
"y": 30,
"side": "right"
}
],
"defaultParams": {
"DataStoreName": "A"
},
"render": {
"type": "image",
"src": "exports/dataStoreRead.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 70,
"height": 60
}
},
{
"type": "selector",
"label": "Selector",
"icon": "selector.svg",
"phases": [
"ALGEBRAIC"
],
"width": 80,
"height": 50,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
}
],
"outputs": [
{
"x": 80,
"y": 25,
"side": "right"
}
],
"defaultParams": {
"Indices": "1"
}
},
{
"type": "reshape",
"label": "Reshape",
"icon": "reshape.svg",
"phases": [
"INIT",
"ALGEBRAIC"
],
"width": 80,
"height": 50,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
}
],
"outputs": [
{
"x": 80,
"y": 25,
"side": "right"
}
],
"defaultParams": {
"OutputDimensions": ""
}
},
{
"type": "concatenate",
"label": "Concatenate",
"icon": "concatenate.svg",
"phases": [
"ALGEBRAIC"
],
"width": 60,
"height": 60,
"inputs": [
{
"x": 0,
"y": 20,
"side": "left"
},
{
"x": 0,
"y": 40,
"side": "left"
}
],
"outputs": [
{
"x": 60,
"y": 30,
"side": "right"
}
],
"defaultParams": {
"ConcatenateDimension": 1
}
},
{
"type": "busCreator",
"label": "Bus Creator",
"icon": "busCreator.svg",
"phases": [
"ALGEBRAIC"
],
"width": 80,
"height": 70,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
},
{
"x": 0,
"y": 45,
"side": "left"
}
],
"outputs": [
{
"x": 80,
"y": 35,
"side": "right"
}
],
"defaultParams": {
"BusType": "",
"NonVirtual": false,
"MemberNames": []
}
},
{
"type": "busSelector",
"label": "Bus Selector",
"icon": "busSelector.svg",
"phases": [
"ALGEBRAIC"
],
"width": 85,
"height": 70,
"inputs": [
{
"x": 0,
"y": 35,
"side": "left"
}
],
"outputs": [
{
"x": 85,
"y": 25,
"side": "right"
},
{
"x": 85,
"y": 45,
"side": "right"
}
],
"defaultParams": {
"SelectedSignals": [],
"OutputAsBus": false
}
},
{
"type": "merge",
"label": "Merge",
"icon": "merge.svg",
"phases": [
"INIT",
"ALGEBRAIC"
],
"width": 40,
"height": 80,
"inputs": [
{
"x": 0,
"y": 30,
"side": "left"
},
{
"x": 0,
"y": 50,
"side": "left"
}
],
"outputs": [
{
"x": 40,
"y": 40,
"side": "right"
}
],
"defaultParams": {
"InitialOutput": 0
},
"render": {
"type": "image",
"src": "exports/merge.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 40,
"height": 80
}
},
{
"type": "functionCallGenerator",
"label": "Function-Call Generator",
"icon": "functionCallGenerator.svg",
"phases": [
"ALGEBRAIC"
],
"width": 90,
"height": 60,
"inputs": [],
"outputs": [
{
"x": 90,
"y": 30,
"side": "right"
}
],
"defaultParams": {
"NumberOfIterations": 1
},
"render": {
"type": "image",
"src": "exports/functionCallGenerator.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 90,
"height": 60
}
},
{
"type": "functionCallSplit",
"label": "Function-Call Split",
"icon": "functionCallSplit.svg",
"phases": [],
"width": 60,
"height": 80,
"inputs": [
{
"x": 0,
"y": 40,
"side": "left"
}
],
"outputs": [
{
"x": 60,
"y": 30,
"side": "right"
},
{
"x": 60,
"y": 50,
"side": "right"
}
],
"defaultParams": {},
"render": {
"type": "image",
"src": "exports/functionCallSplit.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 60,
"height": 80
}
},
{
"type": "iteratorNumber",
"label": "Iterator Number",
"icon": "iteratorNumber.svg",
"phases": [
"OUTPUT"
],
"width": 70,
"height": 50,
"inputs": [],
"outputs": [
{
"x": 70,
"y": 25,
"side": "right"
}
],
"defaultParams": {},
"render": {
"type": "image",
"src": "exports/iteratorNumber.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 70,
"height": 50
}
},
{
"type": "iteratorCondition",
"label": "Iterator Condition",
"icon": "iteratorCondition.svg",
"phases": [
"ALGEBRAIC"
],
"width": 70,
"height": 50,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
}
],
"outputs": [
{
"x": 70,
"y": 25,
"side": "right"
}
],
"defaultParams": {},
"render": {
"type": "image",
"src": "exports/iteratorCondition.svg",
"svgMode": "element",
"preserveAspectRatio": "none",
"x": 0,
"y": 0,
"width": 70,
"height": 50
}
},
{
"type": "width",
"label": "Width",
"icon": "width.svg",
"phases": [
"ALGEBRAIC"
],
"width": 80,
"height": 50,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
}
],
"outputs": [
{
"x": 80,
"y": 25,
"side": "right"
}
],
"defaultParams": {}
},
{
"type": "signalConversion",
"label": "Signal Conversion",
"icon": "signalConversion.svg",
"phases": [
"ALGEBRAIC"
],
"width": 90,
"height": 50,
"inputs": [
{
"x": 0,
"y": 25,
"side": "left"
}
],
"outputs": [
{
"x": 90,
"y": 25,
"side": "right"
}
],
"defaultParams": {}
},
{
"type": "assignment",
"label": "Assignment",
"icon": "assignment.svg",
"phases": [
"ALGEBRAIC"
],
"width": 90,
"height": 60,
"inputs": [
{
"x": 0,
"y": 20,
"side": "left"
},
{
"x": 0,
"y": 40,
"side": "left"
}
],
"outputs": [
{
"x": 90,
"y": 30,
"side": "right"
}
],
"defaultParams": {
"Indices": [
1
]
}
},
{
"type": "busAssignment",
"label": "Bus Assignment",
"icon": "busAssignment.svg",
"phases": [
"ALGEBRAIC"
],
"width": 100,
"height": 60,
"inputs": [
{
"x": 0,
"y": 20,
"side": "left"
},
{
"x": 0,
"y": 40,
"side": "left"
}
],
"outputs": [
{
"x": 100,
"y": 30,
"side": "right"
}
],
"defaultParams": {
"AssignedSignals": []
}
}
]
}
modules/nflow_blocks/src/cpp/routing/assignment.cpp//=============================================================================
// Copyright (c) 2016-present Allan CORNET (Nelson)
//=============================================================================
// This file is part of Nelson.
//=============================================================================
// LICENCE_BLOCK_BEGIN
// SPDX-License-Identifier: LGPL-3.0-or-later
// LICENCE_BLOCK_END
//=============================================================================
// assignment: writes elements into a signal. Port 0 is the base signal (its
// width sets the output width); port 1 carries the replacement values. Indices
// (1-based) selects which base elements are overwritten by the successive values
// i.e. out = base, then out[Indices[k]] = values[k]. Elements not listed pass
// through unchanged. Simulation-only (vector-shape routing, like reshape /
// selector): no scalar code-generation path.
//=============================================================================
#include "SimEngineTypes.hpp"
#include "BlockRegistry.hpp"
#include "FieldNames.hpp"
#include "NFlowBlockDescriptor.hpp"
#include <cmath>
#include "routing_blocks.hpp"
//=============================================================================
bool
Nelson::NFlow::handleAssignment(SimCtx& ctx, const Block& b, Phase phase)
{
if (phase != Phase::ALGEBRAIC) {
return false;
}
if (!hasInput(ctx, b.nid, 0)) {
return false;
}
nflow::BlockDescriptor bd(b, ctx.variables);
const std::vector<double> indices = bd.paramList("Indices");
SigView base = getInputSig(ctx, b.nid, 0);
SigView vals = getInputSig(ctx, b.nid, 1);
return emitElementwise(ctx, b.nid, [&](int i) -> double {
for (size_t k = 0; k < indices.size(); ++k) {
if (static_cast<int>(std::lround(indices[k])) - 1 == i) {
return sigAt(vals, static_cast<int>(k));
}
}
return sigAt(base, i);
});
}
//=============================================================================
d.blocks={ struct('id','b','type','constant','inputs',0,'outputs',1,'params',struct('Value',[1 2 3 4])), struct('id','v','type','constant','inputs',0,'outputs',1,'params',struct('Value',[90 70])), struct('id','a','type','assignment','inputs',2,'outputs',1,'params',struct('Indices',[2 4])), struct('id','w','type','toWorkspace','inputs',1,'outputs',0,'params',struct('VariableName','y','SaveFormat','Array')) };
d.connections={ struct('from','b','to','a','fromIndex',0,'toIndex',0), struct('from','v','to','a','fromIndex',0,'toIndex',1), struct('from','a','to','w','fromIndex',0,'toIndex',0) };
d.sampleTime=0.1; d.duration=0.1; d.solver='discrete'; d.variables=struct();
r=jsondecode(__nflow_simulate__(jsonencode(d)));| Version | Description |
|---|---|
| 1.0.0 | initial version |