{"sections":[{"heading":"Check that the reference equation matches the model","paragraphs":["The constant-resistance overdamped RSJ formula requires the corresponding resistance law, zero capacitance, no thermal-noise drive and appropriate averaging. RTYPE=1 retains a gap-transition branch even if R0 equals RN; that equality alone does not establish the simple analytical model. Changing the number of bias samples cannot remove a physical-model difference.","An initial teaching comparison used RTYPE=1 with R0 = RN and failed at a bias sampled by the finer grid. That was an invalid constant-resistance reference assumption, not evidence of a general solver defect. Correcting the assumption exposed the separate RTYPE=0 gap-dependence comparison below; the original failed runs remain retained."]},{"heading":"Recognise the unresolved gap comparison — KB-IV-001","paragraphs":["On the exercised Windows JoSIM 2.9 candidate, the RTYPE=0, CAP=0, IC=100 µA and RN=R0=10 Ω input with VG=2.8 mV completes its 40-interval IV run but differs from the constant-resistance analytical reference by up to approximately 0.301 mV in the checked high-bias region. It fails the same stated acceptance check used for the numerical control.","At 370 µA, separately authored transient runs with 50 fs and 12.5 fs steps remain approximately 6.70% and 5.48% away from that reference. Smaller steps alone therefore did not resolve the observed difference. The otherwise identical artificial VG=100 mV controls agree within approximately 0.316% and 0.0265%, respectively. These observations identify a relevant gap-region dependency; they do not by themselves settle intended semantics or a root-cause repair.","Source review finds gap-region selection in JJ::getValue and RTYPE-dependent stamping paths, which motivates implementation review. No product correction is claimed. Keep iv_gap_check.cir as a diagnostic and retain the comparison as unresolved. The high-gap control is not a physical workaround for a real junction; do not substitute its gap value into a calibrated model."]},{"heading":"Read IV-specific metadata — KB-IV-002","paragraphs":["The native IV run record correctly identifies model, bias range, point count and voltage/current units in iv_characterization. However, its general effective_settings fields in this checked run report a 2.5 ps step and 100 ps stop, while IV::setup_iv uses 50 fs and 1 ns for the internal helper. Treat those general timing fields as enclosing-job metadata, not as a record of the actual IV helper timing.","The distinction is source-backed and observed in the current native record. The helper controls are not exposed as additional .IV arguments in this guide. For an explicit time-step or settling study, write a transient circuit with the intended source/model and retain its actual time grid; changing an unrelated general setting or increasing N is insufficient proof of helper refinement."]},{"heading":"Use a repeatable diagnosis","steps":["Preserve the complete model, .IV statement, current raw CSV, process/task verdict and exact runtime identity. Check that the x coordinate is voltage and the y values are current.","Confirm 4N+1 rows and bias order. Repeated extrema and a nonzero final interval are expected for this implementation.","State the physical assumptions behind any reference equation and the numerical acceptance criterion. Distinguish a failed assumption from an unresolved model/implementation comparison.","Use explicit transient experiments for time-step and averaging checks. Retain both matching controls and failing diagnostics; do not label an artificial control as a repaired real-device result.","Before sharing, review logs and run records for source paths and private design/licence-status information. No real customer data is needed to reproduce these teaching cases."]}],"canonical_url":"https://www.sun-magnetics.com/knowledge-base/josim-iv-result-checks","url":"/knowledge-base/josim-iv-result-checks","known_issues":[{"disposition":"hold","id":"KB-IV-001","title":"unresolved gap dependence of an RTYPE=0 RSJ reference","public_notice":"The realistic-gap RTYPE=0 diagnostic remains outside accepted numerical results. The artificial high-gap reference is a teaching control, not a physical workaround for a calibrated junction.","claim_scope":"Only the affected claim and recorded build/input; not whole-guide or final-release acceptance"},{"disposition":"supported_path","id":"KB-IV-002","title":"general IV run-record timing differs from helper controls","public_notice":"Distinguish IV helper timing from the enclosing job settings. The general effective_settings record does not establish the internal IV step or averaging window.","claim_scope":"Only the affected claim and recorded build/input; not whole-guide or final-release acceptance"}],"search_record":{"execution":true,"relatedProducts":[],"version_tags":["JoSIM-Pro 2.9 target"],"text":"An IV curve or run record does not match the expected model Separate the resistance law, bias grid, helper transient and record metadata before attributing a mismatch to a simulator failure or accepting software completion as numerical accuracy. JoSIM-Pro 2.9 target; frozen maintained-source Windows candidate Troubleshooting KB-IV-001 KB-IV-002 IV gap dependence RTYPE 0 VG effective_settings IV helper time step IV curve analytical mismatch Check that the reference equation matches the model The constant-resistance overdamped RSJ formula requires the corresponding resistance law, zero capacitance, no thermal-noise drive and appropriate averaging. RTYPE=1 retains a gap-transition branch even if R0 equals RN; that equality alone does not establish the simple analytical model. Changing the number of bias samples cannot remove a physical-model difference. An initial teaching comparison used RTYPE=1 with R0 = RN and failed at a bias sampled by the finer grid. That was an invalid constant-resistance reference assumption, not evidence of a general solver defect. Correcting the assumption exposed the separate RTYPE=0 gap-dependence comparison below; the original failed runs remain retained.  Recognise the unresolved gap comparison — KB-IV-001 On the exercised Windows JoSIM 2.9 candidate, the RTYPE=0, CAP=0, IC=100 µA and RN=R0=10 Ω input with VG=2.8 mV completes its 40-interval IV run but differs from the constant-resistance analytical reference by up to approximately 0.301 mV in the checked high-bias region. It fails the same stated acceptance check used for the numerical control. At 370 µA, separately authored transient runs with 50 fs and 12.5 fs steps remain approximately 6.70% and 5.48% away from that reference. Smaller steps alone therefore did not resolve the observed difference. The otherwise identical artificial VG=100 mV controls agree within approximately 0.316% and 0.0265%, respectively. These observations identify a relevant gap-region dependency; they do not by themselves settle intended semantics or a root-cause repair. Source review finds gap-region selection in JJ::getValue and RTYPE-dependent stamping paths, which motivates implementation review. No product correction is claimed. Keep iv_gap_check.cir as a diagnostic and retain the comparison as unresolved. The high-gap control is not a physical workaround for a real junction; do not substitute its gap value into a calibrated model.  Read IV-specific metadata — KB-IV-002 The native IV run record correctly identifies model, bias range, point count and voltage/current units in iv_characterization. However, its general effective_settings fields in this checked run report a 2.5 ps step and 100 ps stop, while IV::setup_iv uses 50 fs and 1 ns for the internal helper. Treat those general timing fields as enclosing-job metadata, not as a record of the actual IV helper timing. The distinction is source-backed and observed in the current native record. The helper controls are not exposed as additional .IV arguments in this guide. For an explicit time-step or settling study, write a transient circuit with the intended source/model and retain its actual time grid; changing an unrelated general setting or increasing N is insufficient proof of helper refinement.  Use a repeatable diagnosis Preserve the complete model, .IV statement, current raw CSV, process/task verdict and exact runtime identity. Check that the x coordinate is voltage and the y values are current. Confirm 4N+1 rows and bias order. Repeated extrema and a nonzero final interval are expected for this implementation. State the physical assumptions behind any reference equation and the numerical acceptance criterion. Distinguish a failed assumption from an unresolved model/implementation comparison. Use explicit transient experiments for time-step and averaging checks. Retain both matching controls and failing diagnostics; do not label an artificial control as a repaired real-device result. Before sharing, review logs and run records for source paths and private design/licence-status information. No real customer data is needed to reproduce these teaching cases. ","id":"josim-iv-result-checks","keywords":"KB-IV-001 KB-IV-002 IV gap dependence RTYPE 0 VG effective_settings IV helper time step IV curve analytical mismatch","kind":"Troubleshooting","title":"An IV curve or run record does not match the expected model","product":"JoSIM-Pro"},"version":"2.9 target; frozen maintained-source Windows candidate","id":"josim-iv-result-checks","related":["/knowledge-base/josim-iv-characterisation","/knowledge-base/josim-junction-resistance","/knowledge-base/support-effective-report"],"downloads":[],"publication_status":"published","numerical_output":null,"provenance":{"execution_checks":[{"routes":["python-cli"],"scope":"Frozen maintained Windows JoSIM 2.9 CLI with normal licence: artificial high-gap constant-resistance reference, complete realistic-gap diagnostic, explicit transient comparisons and real validation/publication failures. No physical device calibration or acceptance of the held gap case. Seven relevant source files match the maintained NAS exactly; one file differs only in a separately reviewed admission-error message, outside IV execution.","result":"passed","articles":["josim-iv-characterisation","josim-iv-result-checks"],"purpose":"iv-bias-grid-reference-controls-and-failure-recovery","version":"Frozen maintained-source Windows JoSIM 2.9.0 / CPython 3.13.11","id":"VAL-038","records":["24 independent CLI/artifact/source checks","Complete high-gap reference and realistic-gap diagnostic inputs","Original failed comparisons retained; no tolerance widened to accept the gap case","Eight actual browser-download / exact article-and-README command checks pass in a fresh directory; both artificial controls run and the unresolved diagnostic remains unaccepted"],"limit":"The artificial 100 mV gap control isolates a numerical reference; it is not a physical workaround for the unresolved 2.8 mV gap comparison. No physical calibration or universal convergence claim.","observed":{"row_counts":[81,161],"reference_control_max_relative_differences":[0.0038157044689476846,0.0038157044689476846],"realistic_gap_max_abs_reference_difference_V":0.00030148687658798417,"transient_comparisons":[{"mean_voltage_V":0.0038008109972936664,"relative_reference_difference":0.06695342766053763,"samples":20001,"exit_code":0,"header":["time","V(N)"],"vg":"2.8m","time_step":"50f"},{"mean_voltage_V":0.0037576771339407817,"relative_reference_difference":0.05484500569865343,"samples":80001,"exit_code":0,"header":["time","V(N)"],"vg":"2.8m","time_step":"12.5f"},{"mean_voltage_V":0.0035735605957398137,"relative_reference_difference":0.0031603069166326685,"samples":20001,"exit_code":0,"header":["time","V(N)"],"vg":"100m","time_step":"50f"},{"mean_voltage_V":0.003563246871273341,"relative_reference_difference":0.0002650659590357924,"samples":80001,"exit_code":0,"header":["time","V(N)"],"vg":"100m","time_step":"12.5f"}],"reference_control_max_abs_differences_V":[0.000012341063984182016,0.000012163772016930783]}},{"routes":["gui-native-scenario"],"scope":"Normal licensed Windows JoSIM 2.9 native Run, retained voltage/current arrays, current CSV, typed IV metadata, missing-model rejection/recovery and software completion of the unaccepted gap diagnostic. File opens are supplied at the production boundary; no physical picker/export-dialog or final-package claim.","result":"passed","articles":["josim-iv-characterisation","josim-iv-result-checks"],"purpose":"native-iv-voltage-current-view-and-missing-model-recovery","version":"Frozen maintained-source Windows JoSIM GUI 2.9.0 with matching Clang runtime","id":"VAL-039","records":["16 independent native/artifact checks","Two reviewed native charts of the artificial control","Gap case software completion is separate from numerical acceptance"],"limit":"Current native IV data and typed characterization metadata are checked. General effective_settings timing differs from the fixed helper controls (KB-IV-002). Physical pickers/export-dialogs, other platforms and final packages remain pending.","observed":{"row_counts":[81,161],"axis_name":"Voltage","source_fixed_helper_time_step_s":5e-14,"native_csv_max_serialization_differences":{"coarse":{"current_A":5.421010862427522e-20,"voltage_V":5.204170427930421e-18},"gap":{"current_A":5.421010862427522e-20,"voltage_V":4.7704895589362195e-18},"recovered":{"current_A":5.421010862427522e-20,"voltage_V":5.204170427930421e-18},"refined":{"current_A":5.421010862427522e-20,"voltage_V":5.204170427930421e-18}},"general_record_stop_time_s":1e-10,"source_fixed_helper_stop_time_s":1e-9,"trace_unit":"A","axis_unit":"V","general_record_time_step_s":2.5e-12}}],"figure_evidence":[],"review_notes":["The recipe uses an explicitly artificial high-gap control for an analytical check. The complete realistic-gap diagnostic remains available and unaccepted; it is not hidden by changing a tolerance.","The native candidate and relevant numerical path are frozen. Seven selected files match maintained source exactly; one has an unrelated, precisely reviewed admission-error wording difference.","Earlier RTYPE=1 and realistic-gap RTYPE=0 comparisons are retained separately. They do not establish a general solver defect, a calibrated device or an accepted numerical workaround."],"scope":"Recorded inputs/builds only. Complete walkthrough and final-package acceptance remain separate.","verification_requirements":{"gui_method":"not-required-for-this-answer","status":"review-incomplete","illustrations":"not-required-for-this-answer","required":["technical-review","release-applicability","execution","recovery","numerical-interpretation"],"legacy_walkthrough_field":"pending retained; no complete final GUI/package acceptance"},"sources":[{"id":"josim-pro:docs/manual_source/sections/examples.tex","section":"Device and model characterization with .IV; helper-circuit purpose and bias resolution"},{"id":"josim-pro:docs/manual_source/sections/syntax.tex","section":".MODEL junction parameters, .IV and explicit .TRAN syntax; scope and model assumptions remain distinct"},{"id":"josim-pro:docs/manual_source/sections/gui_simulation_results.tex","section":"Current run selection and retained result interpretation"},{"id":"validation:josim-iv-windows-20261104","section":"VAL-038 and VAL-039: complete execution inputs, native voltage/current arrays, analytical controls and explicit KB-IV-001/002 limits"}]},"title":"An IV curve or run record does not match the expected model","type":"Troubleshooting","markdown_url":"/_functions/kbResource?path=markdown%2Fjosim-iv-result-checks.md","summary":"Separate the resistance law, bias grid, helper transient and record metadata before attributing a mismatch to a simulator failure or accepting software completion as numerical accuracy.","product":"JoSIM-Pro"}