vt_resistance.analysisRun.computeResistance

Inputs

item

Scalar DTA item struct. item.curve, or the main curve selected from item.tables, must provide T in seconds, Vf in volts, and Im in amperes. Pt is optional; zero-based sample numbers are generated when absent. item.meta may contain pulse timing and current metadata.

opts

Optional scalar struct described below. Default: struct().

Options

windowMode

Samples used for steady voltage/current medians: "Full pulse median" or "Center 60% median". The latter excludes the first and last 20% of each detected phase. Default: "Full pulse median".

voltageMode

Resistance numerator: "Baseline-corrected dV/I" or "Raw Vf/I". Default: "Baseline-corrected dV/I".

pulseMode

Pulse-detection policy: "Metadata first, then auto", "Metadata only", or "Auto from Im only". Default: "Metadata first, then auto".

Outputs

A

Scalar result struct. Success is indicated by A.ok and A.message="OK". Data-validation failures return ok=false and the fields calculated up to the failed stage.

Result Fields

ok

True when the final mean absolute resistance is finite.

message

"OK" or an explanation of the first failed stage.

windowMode

Effective steady-window label.

voltageMode

Effective voltage-numerator label.

logOnFailure

True when the app should surface the failure in its log.

t

Filtered time vector in seconds.

Vf

Filtered voltage vector in volts.

Im

Filtered current vector in amperes.

pt

Filtered source point numbers or generated zero-based sample numbers.

pulse

Pulse geometry returned by labkit.dta.detectPulses.

detectMode

Detection method that produced pulse.

detectMsg

Pulse-detection status message.

cathMask

Logical samples in the selected cathodic steady window.

anodMask

Logical samples in the selected anodic steady window. cathSteadyStart, cathSteadyEnd - Cathodic steady-window bounds in seconds. anodSteadyStart, anodSteadyEnd - Anodic steady-window bounds in seconds.

Ic_est_A

Median cathodic current in amperes.

Ia_est_A

Median anodic current in amperes.

Vc_ss_V

Median cathodic steady voltage in volts.

Va_ss_V

Median anodic steady voltage in volts. cathBaselineStart, cathBaselineEnd - Requested pre-pulse cathodic baseline bounds in seconds. anodBaselineStart, anodBaselineEnd - Requested post-pulse anodic baseline bounds in seconds.

Vc_baseline_V

Median pre-pulse voltage, or 0 when unavailable.

Va_baseline_V

Median post-pulse voltage; falls back to the cathodic baseline and then 0.

cathBaselineWindow_s

Duration of the requested cathodic baseline window.

anodBaselineWindow_s

Duration of the requested anodic baseline window.

dVc_V

Vc_ss_V-Vc_baseline_V in volts.

dVa_V

Va_ss_V-Va_baseline_V in volts.

Rc_raw_ohm

Vc_ss_V/Ic_est_A in ohms.

Ra_raw_ohm

Va_ss_V/Ia_est_A in ohms.

Rc_dV_ohm

dVc_V/Ic_est_A in ohms.

Ra_dV_ohm

dVa_V/Ia_est_A in ohms.

Rc_ohm

Selected cathodic raw or baseline-corrected resistance.

Ra_ohm

Selected anodic raw or baseline-corrected resistance.

Rc_abs_ohm

Absolute Rc_ohm.

Ra_abs_ohm

Absolute Ra_ohm.

Ravg_abs_ohm

Mean of the finite absolute cathodic and anodic values.

Description

computeResistance analyzes one detected biphasic voltage transient and reports phase-specific as well as averaged resistance. Apps may choose raw steady voltage or subtract the adjacent baseline before division. The function performs no plotting, file selection, or export.

Calculations

Rows containing NaN in T, Vf, or Im are removed together. Pulse detection is delegated to labkit.dta.detectPulses. Steady values are phase-window medians. Division returns NaN when either operand is nonfinite or current is smaller than eps in magnitude. The reported average uses absolute phase resistances so opposite current signs do not cancel.

Failure Behavior

Missing curve data, fewer than five remaining samples, failed pulse detection, undersampled steady windows, or nonfinite final resistance returns ok=false. Malformed structs and unsupported MATLAB value types may still throw from DTA access or numeric operations.

Typical Call

[item, status] = labkit.dta.loadFile("transient.DTA", "chrono");
assert(status.ok, status.message)
opts = struct("windowMode", "Center 60% median", ...
"voltageMode", "Baseline-corrected dV/I", ...
"pulseMode", "Metadata first, then auto");
A = vt_resistance.analysisRun.computeResistance(item, opts);
assert(A.ok, A.message)
fprintf("Mean resistance: %.4g ohm\n", A.Ravg_abs_ohm)