SIGNAL_API_v1

SIGNAL_API_v1

Provider: math.signal 1.0.0. API ID/version: SIGNAL_API_v1/1. This service supplies reusable signal and LTI mathematics for imported or measured data. It produces values and diagnostics; Dataset publication belongs to the existing GX-TXT Publication API. GNU Octave 9.4 and installed signal/control packages are the current backend. Operations are serial and create no worker pool.

Public bindings and discovery

• GNU Octave: gxtxt_signal_v1(family, action, a, b, c, options).
• Tcl: ::GX::SignalAPIv1::call family action a b c ?options? after ::GX::modulePublicApiActivate math.signal SIGNAL_API_v1.
• Registered Octave/Python scripts: gxtxt_api_require('SIGNAL_API_v1@1:math.signal'), then gxtxt_api_call('SIGNAL_API_v1','family.action',{a,b,c,options}) in Octave or a Python list of the same operands.
• ::GX::SignalAPIv1::apiInfo, listOperations, and operationMetadata id expose machine-readable provider identity and the operation catalog. The Script Bridge describes each operation as well.

The Tcl and Script Bridge bindings use typed nodes. An array is {kind=array, shape=[rows,columns,...], real=[values in column-major order], imaginary=[optional matching values]}. Other nodes are {kind=empty}, {kind=text,value=...}, {kind=cell,items=[nodes]}, and {kind=struct,fields={name:node}}. Results use real/imaginary pairs (value_real, value_imaginary) and explicit numerical fields. Dimensions in array nodes are positive; NaN/Inf inputs are rejected. Units are caller-owned except explicit time, frequency_hz, and rate fields. The API never guesses sampling intervals.

Operations

Every row uses the common signature (family, action, a, b, c, options). Optional operands are [] in direct Octave or an empty typed node through the Bridge. Direct Octave accepts ordinary numeric arrays and structs. The operation IDs are family.action in api/operations_v1.tsv.

Errors use GXTXT:Signal:* identifiers in Octave and structured GXTXT SCIENTIFIC <identifier> Tcl codes. Empty, nonfinite, dimensionally inconsistent and invalid policy inputs fail explicitly. Singular deconvolution and zero-energy normalization fail unless the caller chooses a valid conditioning policy. Time and frequency axes must be strictly increasing where used. Complex values are supported for convolution, correlation, filtering, spectral and LTI operations; threshold events and step metrics require real values.

FIR window high-pass and band-stop designs require even order; an odd request fails rather than silently increasing the order. Low/high designs require one edge, while band-pass/stop designs require two increasing edges.

Complex TF/ZPK and state-space inspection, frequency evaluation, impulse/step/input response and ZOH/bilinear conversion use explicit polynomial, matrix-exponential or ODE operations because the installed control package discards imaginary coefficients in several paths. Complex FOH and matched-pole conversion fail with GXTXT:Signal:UnsupportedComplexTime; these are later-scope conversion methods. Real MIMO state-space frequency/time response is supported; conversion to a scalar TF or ZPK is undefined. For a continuous impulse with direct feedthrough, the returned sample series is the regular response and direct_feedthrough_real/imaginary reports the separate Dirac coefficient.

Examples

r = gxtxt_signal_v1('convolution','linear',[1;2],[1;1],[],struct());
assert(isequal(r.value_real,[1;3;2]));

from gxtxt import gxtxt_api_require, gxtxt_api_call
gxtxt_api_require('SIGNAL_API_v1@1:math.signal+convolution')
a = {'kind':'array','shape':[2,1],'real':[1,2]}
b = {'kind':'array','shape':[2,1],'real':[1,1]}
r = gxtxt_api_call('SIGNAL_API_v1','convolution.linear',[a,b,{'kind':'empty'}])

gxtxt_api_require('SIGNAL_API_v1@1:math.signal+convolution');
a=struct('kind','array','shape',[2 1],'real',[1 2]);
b=struct('kind','array','shape',[2 1],'real',[1 1]);
r=gxtxt_api_call('SIGNAL_API_v1','convolution.linear',{a,b,struct('kind','empty')});