PlanMaker IMSUB: Keep subtraction order visible in complex residuals

The 2026 function reference, 2024 reference and 2021 reference were retrieved and read on October 15, 2026. They establish documented support in those PlanMaker manual families. The original introduction and any last-working-version endpoint remain unverified; 2021 is the oldest reference checked here, not an introduction claim. Specific FreeOffice/mobile builds and every desktop platform were not tested.

The tables combine documented function rules with independent component arithmetic and high-precision mathematical calculations. No native PlanMaker execution, screenshot, export or import test was performed. Complex result components are used where native string formatting is not established. English examples use commas between arguments; adapt locale syntax only after checking the installed editor.

The arguments use x+yi or x+yj form. SoftMaker’s example =IMSUB("2+4i","1+2i") gives 1+2i. Neither argument is documented as optional, and the function is not a variable-length subtraction chain. Use nested calls only when the intended order is clear.

The following worksheet constructs both operands from visible numeric coefficients and uses one suffix convention. It does not assume mixed-suffix or malformed-string behavior from another application.

Create ComplexDifferences with X1,Y1,X2,Y2,First,Second,Difference,Real_result,Imag_result in A1:I1. Fill E2 =COMPLEX(A2,B2), F2 =COMPLEX(C2,D2), G2 =IMSUB(E2,F2), H2 =IMREAL(G2) and I2 =IMAGINARY(G2) through row 7.

The independent checks are H=A−C and I=B−D. Numeric components avoid depending on the native string spelling for zero or pure-imaginary results. A copy with G2 changed to =IMSUB(F2,E2) produces coefficients (-1,-2) instead of (1,2).

On a second original copy, change D2 from 2 to -2. The real difference remains 1, while the imaginary difference becomes 6. Subtracting a negative imaginary coefficient increases that component of the residual.

Create ResidualAudit with observed pairs (3,4), (6,8), (-2,5) in A2:B4 and predicted pairs (2,3), (5,10), (-1,4) in C2:D4. Construct the observed and predicted values in E:F, then use =IMSUB(E2,F2) in G2 and fill through row 4.

Expected residual coefficients are (1,1), (1,-2), (-1,1). Their magnitudes, from IMABS, are approximately 1.414213562, 2.236067977, 1.414213562. These are Euclidean distances in a two-component representation, not automatically statistical standardized residuals.

A reconstruction =IMSUM(F2,G2) should have the same mathematical coefficients as E2. For the first row, (2,3)+(1,1)=(3,4). Compare both coefficients rather than only the rendered complex text. Reversing the subtraction would preserve each residual’s magnitude but break this reconstruction convention.

Change the first prediction to (3,4) in a copy. The first residual becomes (0,0) with magnitude 0. The other residuals stay unchanged. This checks that the filled formula uses the appropriate row, not an absolute reference to the first prediction.

When a sign looks wrong, inspect operand order before changing the source data. A magnitude-only audit cannot distinguish z−w from w−z because those differences have equal magnitude. Keep the signed real and imaginary residuals visible.

The reference does not establish every numeric-text coercion, suffix interaction, extreme coefficient limit or exact error display. General spreadsheet arithmetic on a complex representation is not a substitute for a documented IM operation. IMSUM reverses the subtraction in the reconstruction, while IMABS measures the difference without preserving its direction.

Record the exact product/build, edition, platform, locale and workbook format. Enter the full source table, inspect components and apply the changed-input controls on separate copies. Keep full precision for calculations and round only the display. Saved-file recalculation and destination compatibility require their own tests.