IMLOG10 Function (Calligra Sheets)

• Introduced: First release not established; the name is present in Calligra 2.4.0 source.
• Supported in: Calligra Sheets 26.08.2, with no retirement established.
• Scope: Desktop Sheets with the Engineering module. Examples use English semicolon-separated formulas.
• Checked: October 14, 2026. Formulas were executed through the official 25.04.2 engine library and checked against source and independent mathematics. This is not GUI-cell or workbook-import evidence; 26.08.2 was source-checked, not executed.

IMLOG10 calculates the principal complex logarithm to base 10. It is IMLN(z)/LN(10): both real and imaginary components are divided by LN(10). The imaginary component is therefore a scaled phase, not the original phase angle itself. Function help.

=IMLOG10(complexValue)

Exactly one argument is required. Positive, negative and nonreal numeric values are accepted through complex conversion. The ordinary mathematical logarithm requires a nonzero input. Registration and implementation, with versioned help.

Results are shown as (real,imaginary) component pairs, rounded to twelve decimal places, not a literal cell format. A component rounded to zero is shown as 0; the stored value may still contain a tiny residual or signed zero. NaN means not-a-number; infinity and NaN are not finite results.

=IMLOG10(COMPLEX(3;4)) gives approximately 0.698970004336+0.402719196273i. The real component is LOG10(5), because the input magnitude is 5. Its imaginary component is atan2(4,3)/LN(10).

Keep magnitude and phase interpretations separate in a worksheet. If the goal is merely the base-ten logarithm of a magnitude, use the real component deliberately rather than discarding an unexpected imaginary result without checking why it is present.

The executed =IMLOG10(COMPLEX(0;10)) returned real component 1 and imaginary component approximately 0.682188176921, which is (π/2)/LN(10). The magnitude contributes the familiar LOG10(10)=1; the quarter-turn contributes the scaled imaginary component.

Changing logarithm base rescales the principal branch but does not remove its discontinuity. Across a full phase turn, principal values can differ by 2πi/LN(10). As with natural complex logarithms, the logarithm of a product need not equal the sum of principal logarithms without this branch adjustment.

At zero, the tested engine exposed (−Infinity,0) and did not set its error flag. Invalid text and an empty string also became zero and produced nonfinite output. Treat these as invalid finite-log calculations; no GUI display or workbook-import behavior was tested.

TRUE became 1, whose logarithm is zero. Zero or two arguments produced #VALUE!. The positive-real interpretation does not justify assuming the function rejects every negative input: −1+0i is a valid nonzero complex input with a purely imaginary principal logarithm.

The complex conversion helper explains the text and Boolean cases above. The inspected Engineering module and complex converter are byte-identical between 25.04.2 and 26.08.2. That source comparison does not establish every locale, import path or extreme-value case.

Use COMPLEX to construct values from numeric components, IMABS for magnitude, and IMARGUMENT for principal phase.