\section{Domain report presets}
Load \key{\usegradbarslibrary{reports}} in the preamble. It adds correlation,
ablation and metric recipes through the existing table and legend libraries.
These presets display supplied data; they do not compute statistical estimates.
\begin{demo}{A fixed-scale correlation matrix}
\begin{center}
\begin{gradtable}[align=c,header align=c,style=correlation]
\gradcolumn{name}{Variable}
\gradcorrelationcolumn{a}{A}
\gradcorrelationcolumn{b}{B}
\gradrow{A,1,-.38}\gradrow{B,-.38,1}
\end{gradtable}
\end{center}
\end{demo}
Standalone \key{\gradcorrelation{r}} fixes [-1,1], keeps zero white, uses two
decimals and rejects values outside the correlation range. NA is missing.
The matrix recipe does not check symmetry, significance or positive semidefiniteness.
\begin{demo}{Ablation observations: reference/current}
\begin{center}
\begin{gradtable}[align=c,header align=c,style=ablation]
\gradcolumn{name}{Variant}
\gradablationcolumn{score}{Score change}
\gradrow{Without feature,80/76}
\gradrow{With extra data,80/84}
\end{gradtable}
\end{center}
\end{demo}
\key{\gradablation[options]{reference}{current}} draws the same dumbbell alone.
Its delta is current minus reference in the supplied units, not a significance
test or an inferred percent change. The default range is [0,100].
\begin{demo}{Metrics with separate directions and units}
\begin{center}
\begin{gradtable}[align=c,header align=c,style=metrics,width=\linewidth]
\gradcolumn{name}{Model}
\gradmetriccolumn{acc}{Accuracy}
\gradmetriccolumn[options={style=report-metric,
  better=lower,unit={ ms},precision=1}]{lat}{Latency}
\gradrow{A,92,35}\gradrow{B,95,48}\gradrow{C,90,28}
\end{gradtable}
\end{center}
\end{demo}
\key{\gradmetric{value}} is the standalone [0,100] preset. Native metric columns
scan their own ranges and mark best/second values; lower-is-better must be stated
for costs. No combined score is invented. Column keys override recipe defaults;
when replacing options, retain the desired report graphic style. Full examples
and limits are in \key{docs/reports.md} and \key{docs/examples/domain-reports.tex}.