R.QGUMBEL Function (Gnumeric)

• Introduced: Introduced in Gnumeric 1.12.25 release notes.
• Supported in: Gnumeric 1.12.62; no retirement is established.
• Scope: Desktop Gnumeric with its Statistical Functions From R plugin. English comma-separated formulas are shown.
• Checked: October 14, 2026. Tables and the named advanced check use 1.12.57 ssconvert. Current 1.12.62 source was inspected; that release was not executed.

R.QGUMBEL returns the maximum-type Gumbel quantile. For an ordinary lower probability p between 0 and 1, the formula is location−scale×LN(−LN(p)). Upper-tail mode interprets the input as the complement; log_p accepts its natural logarithm. Versioned function help.

=R.QGUMBEL(probability,location,scale[,lower_tail[,log_p]])

Probability, location and scale are required. Scale must be positive. lower_tail defaults to TRUE and log_p to FALSE. Unlike a positive-support distribution, the Gumbel support extends toward both negative and positive infinity.

Brackets mark optional arguments; do not type them. Current worksheet implementation.

These self-contained formulas were recalculated natively. Ordinary-domain results were checked against independent mathematics; source guards explain the boundary cases. Results are rounded to twelve decimal places, or thirteen significant digits for small nonzero values. This is presentation precision, not a universal accuracy guarantee.

For location 0 and scale 1, the median is approximately 0.366512920582, so it is not equal to location. The 90th percentile is approximately 2.250367327312. Upper probability 0.1 produces the same threshold.

For location 2 and scale 3, the median is approximately 3.099538761745. The standard median is scaled by 3 and then shifted by 2. This affine relationship is useful when checking parameter order in a worksheet.

A lower probability of EXP(−1) corresponds exactly to location mathematically. The saved formula with standard parameters returns zero; the log-probability form with input −1, location 2 and scale 3 returns 2.

The advanced CDF reconstruction below returns 0.9 at the computed 90th percentile for location 2 and scale 3. The two equivalent log/ordinary probability examples differ only at the last stored place in one native result, so their shared twelve-decimal display is not a claim of bitwise equality.

The saved advanced-check result for =R.PGUMBEL(R.QGUMBEL(.9,2,3),2,3) was 0.9.

Both probability endpoints require infinite cutoffs and become #NUM!, in either tail convention. Probability below zero or above one is invalid; a positive log probability is also invalid. Log probability zero represents probability one and reaches an endpoint.

Zero or negative scale gives #NUM!. Nonnumeric text gives #VALUE!; empty F5 becomes probability zero and therefore errors. Wrong arity gives #N/A. A quantile is a cutoff in observation units, not a probability or a fitted estimate of the location parameter.

F5 is genuinely empty, rather than a cell containing an empty string.

• Current worksheet callback
• Tested-version worksheet callback
• Current qgumbel calculation
• Tested-version qgumbel calculation
• Nonfinite worksheet-value handling
• Statistical Functions From R plugin declaration

The relevant complete worksheet callback and main calculation helper are unchanged between the inspected versions. That does not establish later-version numerical execution. Both stale and uncached SUM controls recalculated correctly. Native XML preserves the R.* identities. The secondary ODF export keeps these calls in the ORG.GNUMERIC namespace; it does not establish execution in another product. GUI entry, other locales and other spreadsheet products were not tested.

LN, EXP, R.QNORM.