From 684bb2ca507cb1eae449ab1a906d280b85857dbc Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Fri, 18 Sep 2026 19:51:57 +0200
Subject: [PATCH] Parameters: draft the cases of a generic feed-join

In the general case, a base value and a feed can also be combined
when the metric of both arguments differs; notably a linear multiplier
can be applied to an logarithmic base value by adding its logarithm,
and a logarithmic feed can be multiplied to a linear base value by
taking the exponential function.

Furthermore there are some cases involving nominal scales, which we can mark only, but leave unimplemented
---
 src/lib/par/scale.hpp    | 64 ++++++++++++++++++++++++++++++++++++++--
 wiki/thinkPad.ichthyo.mm | 51 ++++++++++++++++++++++++++++----
 2 files changed, 107 insertions(+), 8 deletions(-)

diff --git a/src/lib/par/scale.hpp b/src/lib/par/scale.hpp
index 0a31f0f55..48da2451c 100644
--- a/src/lib/par/scale.hpp
+++ b/src/lib/par/scale.hpp
@@ -87,6 +87,16 @@ namespace par {
       template<typename SRC>
       VAL join (VAL const&, SRC const&, Scale<SRC> const&) const;
       VAL join (VAL const&, VAL const&)                    const;
+      
+    private:
+      template<typename TAR>
+      VAL asFactor (VAL const&)  const;
+      
+      template<typename TAR>
+      VAL baseScale (Metric targetMetric)  const;
+      
+      template<typename TAR>
+      VAL asLogarithm (Metric targetMetric, VAL const&)  const;
     };
   
   
@@ -195,8 +205,34 @@ namespace par {
   inline VAL
   Scale<VAL>::join (VAL const& value, SRC const& srcFeed, Scale<SRC> const& feedScale) const
   {
-    VAL feed(preClamp<VAL> (srcFeed));
-    return join (value, feed);
+    VAL res{};
+    if (NOM == metric)
+      UNIMPLEMENTED ("nominal and ordinal scales");
+    if (LIN == metric)
+      {
+        if (feedScale.isLogarithmic())
+          assignConverted (res, value * feedScale.template asFactor<VAL> (srcFeed));
+        else
+        if (this->isFactor())
+          assignConverted (res, value * srcFeed);
+        else
+          assignConverted (res, value + srcFeed);
+      }
+    else
+    if (this->isLogarithmic())
+      {
+        if (feedScale.isLogarithmic())
+          assignConverted (res, value + feedScale.template baseScale<VAL>(metric) * srcFeed);
+        else
+        if (feedScale.isFactor())
+          assignConverted (res, value + feedScale.template asLogarithm<VAL> (metric, srcFeed));
+        else
+          throw err::Invalid {"adding a non-logarithmic data feed on top of a logarithmic base value is pointless."};
+      }
+    else
+      NOTREACHED ("Unexpected metric conversion case");
+    
+    return conform (res);
   }
   
   /**
@@ -211,6 +247,30 @@ namespace par {
                    );
   }
   
+  template<typename VAL>
+  template<typename TAR>
+  inline VAL
+  Scale<VAL>::asFactor (VAL const& value)  const
+  {
+    UNIMPLEMENTED ("transform a logarithmic value into an exponential factor");
+  }
+  
+  template<typename VAL>
+  template<typename TAR>
+  inline VAL
+  Scale<VAL>::baseScale (Metric targetMetric)  const
+  {
+    UNIMPLEMENTED ("provide the adaptation factor from this logarithmic scale to the given other logarithmic scale");
+  }
+  
+  template<typename VAL>
+  template<typename TAR>
+  inline VAL
+  Scale<VAL>::asLogarithm (Metric targetMetric, VAL const& value)  const
+  {
+    UNIMPLEMENTED ("transform this value into a suitable logarithm for the target scale");
+  }
+  
   
 }} // namespace lib::par
 #endif /*LIB_PAR_SCALE_H*/
diff --git a/wiki/thinkPad.ichthyo.mm b/wiki/thinkPad.ichthyo.mm
index d71bdc78f..e9785a1d7 100644
--- a/wiki/thinkPad.ichthyo.mm
+++ b/wiki/thinkPad.ichthyo.mm
@@ -85612,10 +85612,9 @@
 </node>
 <node CREATED="1789679178010" ID="ID_641923682" MODIFIED="1789679196411" TEXT="dazu gen&#xfc;gt die preClamp-Funktion (generisch, mit Varianten)"/>
 <node CREATED="1789679234347" ID="ID_562560611" MODIFIED="1789679253968" TEXT="diese h&#xe4;ngt aber (mit diversen weiteren Funktionen) in param-type.hpp"/>
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1789679364793" ID="ID_1241002579" MODIFIED="1789681307994" TEXT="extrahieren in type-handler.hpp">
-<arrowlink COLOR="#723f52" DESTINATION="ID_517472625" ENDARROW="Default" ENDINCLINATION="368;-30;" ID="Arrow_ID_914959509" STARTARROW="None" STARTINCLINATION="-203;15;"/>
+<node COLOR="#435e98" CREATED="1789679364793" ID="ID_1241002579" MODIFIED="1789690095158" STYLE="fork" TEXT="extrahieren in type-handler.hpp">
+<arrowlink COLOR="#3f4b72" DESTINATION="ID_517472625" ENDARROW="Default" ENDINCLINATION="368;-30;" ID="Arrow_ID_914959509" STARTARROW="None" STARTINCLINATION="-199;17;"/>
 <icon BUILTIN="yes"/>
-<icon BUILTIN="flag-yellow"/>
 </node>
 </node>
 <node CREATED="1789165444623" ID="ID_1649021234" MODIFIED="1789165459491" TEXT="vereinfachte Variante f&#xfc;r identische Scale"/>
@@ -85641,9 +85640,49 @@
 <icon BUILTIN="yes"/>
 </node>
 <node CREATED="1789681257536" ID="ID_1700836715" MODIFIED="1789681261057" TEXT="Implementierung">
-<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1789681263702" ID="ID_517472625" MODIFIED="1789681294765" TEXT="type-handler.hpp verwenden">
-<linktarget COLOR="#723f52" DESTINATION="ID_517472625" ENDARROW="Default" ENDINCLINATION="368;-30;" ID="Arrow_ID_914959509" SOURCE="ID_1241002579" STARTARROW="None" STARTINCLINATION="-203;15;"/>
-<icon BUILTIN="flag-yellow"/>
+<node COLOR="#338800" CREATED="1789681263702" ID="ID_517472625" MODIFIED="1789690087703" TEXT="type-handler.hpp verwenden">
+<linktarget COLOR="#3f4b72" DESTINATION="ID_517472625" ENDARROW="Default" ENDINCLINATION="368;-30;" ID="Arrow_ID_914959509" SOURCE="ID_1241002579" STARTARROW="None" STARTINCLINATION="-199;17;"/>
+<icon BUILTIN="button_ok"/>
+</node>
+<node CREATED="1789690189866" ID="ID_1376240578" MODIFIED="1789690197006" TEXT="Einzelf&#xe4;lle...">
+<node CREATED="1789690461895" ID="ID_1698758358" MODIFIED="1789690470825" TEXT="Ziel linear">
+<node CREATED="1789690555041" ID="ID_1115887554" MODIFIED="1789690584237" TEXT="Quelle logarithmisch &#x27f9; in Faktor verwandeln"/>
+<node CREATED="1789690484811" ID="ID_1985479365" MODIFIED="1789690540680" TEXT="Quelle multiplikativ &#x27f9;  Feed multiplizieren"/>
+<node CREATED="1789690518951" ID="ID_369458503" MODIFIED="1789690532408" TEXT="sonst: &#x27f9; Feed addieren"/>
+</node>
+<node CREATED="1789690604246" ID="ID_1698111641" MODIFIED="1789690609463" TEXT="Ziel logarithmisch">
+<node CREATED="1789690612021" ID="ID_699494084" MODIFIED="1789690620205" TEXT="Quelle logarithmisch">
+<node CREATED="1789690621353" ID="ID_369958191" MODIFIED="1789690631911" TEXT="ggfs Basis-Anpassungsfaktor"/>
+<node CREATED="1789690632759" ID="ID_169878566" MODIFIED="1789690643602" TEXT="sonst &#x27f9; Feed addieren"/>
+</node>
+<node CREATED="1789690650447" ID="ID_763848405" MODIFIED="1789690934324" TEXT="Quelle multiplikativ &#x27f9; logarithmieren und addieren"/>
+<node CREATED="1789690952586" ID="ID_806764948" MODIFIED="1789690977990" TEXT="sonst delogarithmieren, Feed addieren, re-logarithmieren"/>
+</node>
+<node CREATED="1789691026066" ID="ID_1521422421" MODIFIED="1789691072009" TEXT="Ziel ordinal und Quelle additiv(linear) &#x27f9; Ordinal-Step"/>
+<node CREATED="1789691081395" ID="ID_1029470467" MODIFIED="1789691128539" TEXT="Ziel nominal und Quelle nominal oder linear &#x27f9; Feed(codiert) ersetzt Quelle"/>
+</node>
+<node CREATED="1789691154922" ID="ID_1884775055" MODIFIED="1789691157587" TEXT="Berechnung">
+<node CREATED="1789691206195" ID="ID_521077468" MODIFIED="1789691213662" TEXT="Genauigkeit steigern">
+<node CREATED="1789691368028" ID="ID_1992504549" MODIFIED="1789691686368" TEXT="de/Logarithmieren : stets bestm&#xf6;glichen Floating-Point">
+<node CREATED="1789691697643" ID="ID_1724775924" MODIFIED="1789691708345" TEXT="von Integraltypen &#x27f9; stets double"/>
+<node CREATED="1789691709035" ID="ID_28970072" MODIFIED="1789691791715" TEXT="ansonsten maximalen floating-point-Typ">
+<richcontent TYPE="NOTE"><html>
+  <head>
+    
+  </head>
+  <body>
+    <p>
+      d.h. wenn beide Seiten float sind, dann ist das wohl auch so beabsichtigt, und wir bleiben in der float-Dom&#228;ne. Ebenso wenn eine Seite long-double ist, dann alles dort. Sonst double verwenden
+    </p>
+  </body>
+</html>
+</richcontent>
+</node>
+</node>
+<node CREATED="1789691232896" ID="ID_575039816" MODIFIED="1789691803456" TEXT="Konvertierung in den Ziel-Typ stets zuletzt (vor Conform)"/>
+</node>
+<node CREATED="1789691159130" ID="ID_1328281700" MODIFIED="1789691168924" TEXT="zuletzt Conform() anwenden"/>
+<node CREATED="1789691889609" ID="ID_569629897" MODIFIED="1789691899860" TEXT="Formulierung: mu&#xdf; Funktions-Kette bilden"/>
 </node>
 </node>
 </node>