## 3 Results
### Expert Evaluation and Ratings  
One expert on jazz standards (among the authors) was involved in a process of analyzing, commenting in free form and rating a selection of 13 generated harmonizations. The expert would listen to the results and then a digital version of the score was marked. The expert was conducting this process as if he was evaluating students in a harmonization course. The process is explained graphically in Figure 2. The jazz standards that were involved in the re-harmonization sessions were selected based on some exceptional characteristics that they incorporated, according to the expert; the re-harmonizations that are involved in the analysis, along with the ratings in melody, transitions and the average of the two are shown in Table 4. The videos and the log files can be found online (link can be found here: [[https://doi.org/10.5281/zenodo.7549632](https://doi.org/10.5281/zenodo.7549632)]([https://doi.org/10.5281/zenodo.7549632](https://doi.org/10.5281/zenodo.7549632)), last accessed on 19 January 2023). Figure 2: Experimental process pipeline. Pairs of jazz standards are selected and the system employs the presented methods to generate cross-harmonizations between them, along with the respective explanatory log files. The cross-harmonization output is imported to GJT and rendered to video/audio format (one repetition) in jazz trio format (drums, bass and piano). The melody, generated in Garage Band, is imported to the video and the final outcome becomes available to a jazz expert. The expert analyzes the output in free text and the most important comments are gathered. They also rate each harmonization and the correlation is examined between those ratings and several aspects of the generated harmonizations from the log files produced by the system. \begin{table}
\begin{tabular}{l c c c c c c c} \hline  & **Constr.** & **Supp.** & **Supp-nC** & **Mel.** & **New** & **Smith.** & **Smith-nC** \\ \hline
**Constr.** & \(1.00\) & \(0.13\) & \(-0.13\) & \(0.00\) & \(0.17\) & \(0.09\) & \(-0.05\) \\
**Supp.** & \(0.13\) & \(1.00\) & \(0.96\) & \(0.15\) & **0.62** & \(0.28\) & \(0.26\) \\
**Supp-nC** & \(-0.13\) & \(0.96\) & \(1.00\) & \(0.15\) & **0.57** & \(0.25\) & \(0.27\) \\
**Mel.** & \(0.00\) & \(0.15\) & \(0.15\) & \(1.00\) & \(0.12\) & \(-0.15\) & \(-0.18\) \\
**New** & \(0.17\) & **0.62** & **0.57** & \(0.12\) & \(1.00\) & \(0.15\) & -0.00 \\
**Smith.** & \(0.09\) & \(0.28\) & \(0.25\) & \(-0.15\) & \(0.15\) & \(1.00\) & \(0.64\) \\
**Smith-nC** & \(-0.05\) & \(0.26\) & \(0.27\) & \(-0.18\) & \(-0.00\) & \(0.64\) & \(1.00\) \\ \hline \end{tabular}
\end{table} 
Table 3: Results of correlation analysis on all generated pieces, for examining relations between constraints, support/smoothing (on constraints or independent), melody matching and the employment of new chords. The following features are examined (a value per feature for each piece): **Constr. **: ratio of constraints over transitions. **Supp./Smith./New**: ratio of times support/smoothing/appearance of new chord was presented over transitions. **-nC** suffix: not coming exactly before, after or over constraint. **Mel**: melody matching value (of \(O^{N\times K}\)). According to the expert analysis, which provided useful insight for the discussion in Section 4.2, the system performed well on several occasions, sometimes even surprisingly well, while, in other cases, some chord decisions were lacking adaptation to the underlying melody and/or harmonic coherence in terms of both chord transitions and individual chord choices. Regarding poor chord choices, an example is the employment of a mb6 chord in the first bar of a harmonization; this chord, in the jazz standard idiom, has been employed almost solely as a transitional chord between a m6 and a minor triad chord. Regarding melody mismatches, the system, on some occasions, harmonized melody pitches that are included in the \"avoid notes\" of jazz standard terminology, e.g., a major third over a minor chord, or the 11 th over a major chord.