{ "category": "Engineering functions", "display_name": "IMSUB", "entry_kind": "built_in_function", "eval_api": { "method": "POST", "url": "https://handbook.dnacalc.com/api/eval" }, "function_id": "FUNC.IMSUB", "implementation_state": { "answer_bank": { "excel_builds": [ "20430" ], "larger_numeric": 0, "last_bit": 0, "matched": 1216, "other_mismatch": 0, "refused": 0, "rows": 1216, "unread": 0, "worst_ulp": 0 }, "detail": "Recorded: 1,216 in the answer bank and 4 workbook cells.", "dnacalc_commit": "9e1884369a678158dd82d3d74188daf986995e87", "in_catalogue": true, "state": "matches", "state_label": "Matches every recorded Excel answer", "summary": "Matches all 1,220 recorded answers", "workbook_corpus": { "cells": 4, "matched": 4 } }, "implementations": [ { "commit": "9e1884369a678158dd82d3d74188daf986995e87", "flavour": "excel-compatibility-candidate", "language": "Rust", "name": "CalcFunc", "own_code": [ "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/engineering.rs#L245-L249" ], "repository": "https://github.com/DnaCalc/DnaCalc", "shared_code": [ "catalogue/engineering::complex_of", "catalogue/engineering::complex_text", "ported/complex_decimal::nearest_even", "ported/complex_decimal::decimal_pair", "ported/complex_family::parse_ascii_decimal_15", "ported/complex_family::ParsedComplex::new", "ported/complex_family::ParsedComplex::abs", "ported/complex_family::normalize_zero", "ported/complex_family::number_to_excel_text", "ported/complex_family::format_complex_text", "ported/complex_family::parse_real_number", "ported/complex_family::find_real_imag_split", "ported/complex_family::parse_imag_coeff", "ported/complex_family::parse_complex_text", "ported/complex_family::suffix_from_operands" ], "source": "https://github.com/DnaCalc/DnaCalc/blob/9e1884369a678158dd82d3d74188daf986995e87/crates/calc-func/src/catalogue/engineering.rs#L245-L249", "state": "matches", "suite": null, "summary": "Matches all 1,220 recorded answers" } ], "json_url": "https://handbook.dnacalc.com/api/functions/FUNC.IMSUB.json", "name": "IMSUB", "notes": [], "schema": "efh.function-reference/v1", "section_order": [ "what-it-does", "try-it", "quirks", "how-to-implement", "version-differences", "alternatives" ], "sections": { "alternatives": "\n[COMPLEX](FUNC.COMPLEX.md) constructs each input; [IMDIV](FUNC.IMDIV.md) divides; [IMPOWER](FUNC.IMPOWER.md) raises one input to a real power.\n\n\n", "how-to-implement": "\nParse the two coefficients and suffix before doing arithmetic; use the common complex formatter afterward. Retain suffix consistency, suppress a zero component and omit the coefficient one before the imaginary unit. Formatting and parsing have their own fifteen-significant-digit rules, so testing only the algebra misses observable behaviour.\n\nCompute `(a,b)-(c,d)=(a-c,b-d)`. The example gives `5-1=4` and `2-5=-3`. Preserve operand order; subtraction is not commutative. The current implementation uses ordinary binary64 component arithmetic. Keep error propagation and traversal of range arguments consistent with the worksheet call model; flattening values without their error policy can change which result is returned.\n\n\n", "quirks": "\nOperand order matters: subtraction is neither commutative nor associative. Both arguments are required. Complex text may use lowercase `i` or `j`, but two written suffixes must agree or the current wrapper gives `#VALUE!`. A malformed complex number gives `#NUM!`. The result is complex text; extracting its coordinates with IMREAL and IMAGINARY returns ordinary numbers.\n\n\n", "sources": "\n- [Microsoft: IMSUB function](https://support.microsoft.com/en-us/office/imsub-function-2e404b4d-4935-4e85-9f52-cb08b9a45054), opened 6 November 2026; syntax, documented argument rules and errors.\n- [DnaCalc implementation](https://github.com/DnaCalc/DnaCalc/blob/da3ecc4fb19a3a5529708c311d0e8f05688ac165/crates/calc-func/src/ported/complex_family.rs); implementation steps and the limits identified in the text.\n\n", "try-it": "\n`=IMSUB(\"5+2i\",\"1+5i\")` returns `\"4-3i\"`: subtract real coefficients and imaginary coefficients separately. Reversing the arguments returns `\"-4+3i\"`.\n\n\n", "version-differences": "The recorded environments below distinguish a reading from a same-input comparison. Counts describe captured inputs in each environment; overlapping captures and comparisons are not totals of unique worksheet calls.\n\n| Excel 16.0 build | Platform and CPU | Captured inputs |\n|---|---|---:|\n| 20430 | Windows, 64-bit, CPU not recorded | 1,216 |\n\nThe record contains no same-input comparison between these environments. Reading different inputs on different builds does not establish either a version change or cross-build agreement.\n\n[Recorded environments and comparison details](https://github.com/DnaCalc/ExcelFunctionsHandbook/blob/5dc75391aa5125ccc5abdb095da85950980d6fd8/content/evidence/environments/FUNC.IMSUB.json).", "what-it-does": "\n`IMSUB(inumber1, inumber2)` subtracts its second complex argument from its first. Both arguments are required.\n\n\n" }, "signature": { "display": "IMSUB(inumber1, inumber2)", "parameters": [ { "description": null, "name": "inumber1", "optional": false, "repeats": false }, { "description": null, "name": "inumber2", "optional": false, "repeats": false } ], "trailing_repeats": false }, "sources": { "metadata": { "admission": { "label": "implemented", "reason": null }, "arity": { "max": 2, "min": 2 }, "category": "Engineering functions", "classification": { "arg_preparation_profile": "ValuesOnlyPreAdapter", "coercion_lift_profile": "Custom", "determinism_class": "Deterministic", "error_collapse_profile": "None", "fec_dependency_profile": "None", "host_interaction_class": "None", "kernel_signature_class": "Custom", "rich_value_usage": "RichBlind", "surface_fec_dependency_profile": "None", "thread_safety_class": "SafePure", "volatility_class": "NonVolatile" }, "descriptions": { "long": null, "short": "One complex number minus another", "short_source": "dna-calc-own" }, "docs": { "english_description": "Returns the difference between two complex numbers", "microsoft_url": "https://support.microsoft.com/en-us/office/imsub-function-2e404b4d-4935-4e85-9f52-cb08b9a45054" }, "entry_kind": "built_in_function", "localized_family_names": null, "localized_names": [ { "locale": "ar-SA", "name": "IMSUB" }, { "locale": "bg-BG", "name": "IMSUB" }, { "locale": "cs-CZ", "name": "IMSUB" }, { "locale": "da-DK", "name": "IMAGSUB" }, { "locale": "de-DE", "name": "IMSUB" }, { "locale": "el-GR", "name": "IMSUB" }, { "locale": "en-AU", "name": "IMSUB" }, { "locale": "en-GB", "name": "IMSUB" }, { "locale": "en-US", "name": "IMSUB" }, { "locale": "es-ES", "name": "IM.SUSTR" }, { "locale": "et-EE", "name": "IMSUB" }, { "locale": "fi-FI", "name": "KOMPLEKSI.EROTUS" }, { "locale": "fr-FR", "name": "COMPLEXE.DIFFERENCE*" }, { "locale": "he-IL", "name": "IMSUB" }, { "locale": "hr-HR", "name": "IMSUB" }, { "locale": "hu-HU", "name": "KÉPZ.KÜL" }, { "locale": "id-ID", "name": "IMSUB" }, { "locale": "it-IT", "name": "IMSUB" }, { "locale": "ja-JP", "name": "IMSUB" }, { "locale": "ko-KR", "name": "IMSUB" }, { "locale": "lt-LT", "name": "IMSUB" }, { "locale": "lv-LV", "name": "IMSUB" }, { "locale": "nb-NO", "name": "IMSUB" }, { "locale": "nl-NL", "name": "C.VERSCHIL" }, { "locale": "pl-PL", "name": "RÓŻN.LICZB.ZESP" }, { "locale": "pt-BR", "name": "IMSUB" }, { "locale": "pt-PT", "name": "IMSUBTR" }, { "locale": "ro-RO", "name": "IMSUB" }, { "locale": "ru-RU", "name": "МНИМ.РАЗН" }, { "locale": "sk-SK", "name": "IMSUB" }, { "locale": "sl-SI", "name": "IMSUB" }, { "locale": "sr-Latn-RS", "name": "IMSUB" }, { "locale": "sv-SE", "name": "IMDIFF" }, { "locale": "th-TH", "name": "IMSUB" }, { "locale": "tr-TR", "name": "SANTOPLA" }, { "locale": "uk-UA", "name": "IMSUB" }, { "locale": "vi-VN", "name": "IMSUB" }, { "locale": "zh-CN", "name": "IMSUB" }, { "locale": "zh-HK", "name": "IMSUB" }, { "locale": "zh-TW", "name": "IMSUB" } ], "signature": { "display": "IMSUB(inumber1, inumber2)", "parameters": [ { "description": null, "name": "inumber1", "optional": false, "repeats": false }, { "description": null, "name": "inumber2", "optional": false, "repeats": false } ], "trailing_repeats": false }, "surface_name": "IMSUB", "version_marker": null, "xlcall": { "code": "396", "symbol": "xlfImsub" } }, "microsoft": "https://support.microsoft.com/en-us/office/imsub-function-2e404b4d-4935-4e85-9f52-cb08b9a45054" }, "try_it": { "formula": "=IMSUB(\"5+2i\",\"1+5i\")" }, "url": "https://handbook.dnacalc.com/functions/IMSUB.html", "variants": [], "versions": [ { "behaviour": "1,216 captured inputs are indexed for this environment. Capture dates: 2026-09-29 to 2026-09-29. This is a reading count, not a comparison with another build.", "excel_build": "16.0 build 20430", "platform": "Windows, 64-bit, CPU not recorded", "sources": [ "https://github.com/DnaCalc/ExcelFunctionsHandbook/blob/5dc75391aa5125ccc5abdb095da85950980d6fd8/content/evidence/environments/FUNC.IMSUB.json" ] } ] }