JAL-2418 JAL-1632 JAL-2416 calculations dialog documentation page and release notes

[jalview.git] / help / html / calculations / pca.html

diff --git a/help/html/calculations/pca.html b/help/html/calculations/pca.html
index c38d9ac..7ffb160 100755 (executable)
--- a/help/html/calculations/pca.html
+++ b/help/html/calculations/pca.html
@@ -26,16 +26,20 @@
   <p>
     <strong>Principal Component Analysis</strong>
   </p>
+  <p>A principal component analysis can be performed via the 
+  <a href="calculations.html">calculations dialog</a> which is accessed by selecting <strong>Calculate&#8594;Calculate
+      Tree or PCA...</strong>.</p>
   <p>This calculation creates a spatial representation of the
     similarities within a selected group, or all of the sequences in an
     alignment. After the calculation finishes, a 3D viewer displays the
     set of sequences as points in 'similarity space', and similar
     sequences tend to lie near each other in the space.</p>
   <p>
-    <em>Caveats</em><br />The calculation is computationally expensive,
-    and may fail for very large sets of sequences - usually because the
-    JVM has run out of memory. A future release of Jalview will be able
-    to avoid this by executing the calculation via a web service.
+    <em>Caveats</em><br />The calculation can be computationally
+    expensive, and may fail for very large sets of sequences - usually
+    because the JVM has run out of memory. However, the PCA
+    implementation in Jalview 2.10.2 employs more memory efficient
+    matrix storage structures, allowing larger PCAs to be performed.
   </p>
 
   <p>