Added explanation to fmi3{Get|Set}{Interval|Shift}Fraction arguments (#…

…1993)

* Added explanation to fmi3{Get|Set}{Interval|Shift}Fraction arguments

* Update docs/2_2_common_mechanisms.adoc

Co-authored-by: Pierre R. Mai <[email protected]>

* Update docs/2_2_common_mechanisms.adoc

Co-authored-by: Pierre R. Mai <[email protected]>

---------

Co-authored-by: NikolaiFa <[email protected]>
Co-authored-by: Pierre R. Mai <[email protected]>

docs/2_2_common_mechanisms.adoc

@@ -716,7 +716,7 @@ is a time-based Clock whose next interval is unchangeably known right after the
 +
 The next Clock tick at time instant latexmath:[t_i] is defined as: +
 latexmath:[\begin{align*}
-t_0 &:= t_{\mathit{start}} + T_{\mathit{interval, 0}} \\
+t_0 &:= t_{\mathit{start}} + T_{\mathit{interval}, 0} \\
 t_i &:= t_{i-1} + T_{\mathit{interval, i}} \qquad i = 1,2,3,{...}
 \end{align*}]
 
@@ -726,7 +726,7 @@ t_i &:= t_{i-1} + T_{\mathit{interval, i}} \qquad i = 1,2,3,{...}
 [cols="1,2"]
 |===
 
-|latexmath:[T_{\mathit{interval, 0}} \geq 0]
+|latexmath:[T_{\mathit{interval}, 0} \geq 0]
 |The time interval from latexmath:[t_{\mathit{start}}] to first Clock tick.
 Must be retrieved using <<fmi3GetInterval>> in <<InitializationMode>>.
 
@@ -742,7 +742,7 @@ The return argument <<qualifiers>> of <<fmi3GetInterval>> is used to indicate if
 +
 The next Clock tick at time instant latexmath:[t_i] is defined as: +
 latexmath:[\begin{align*}
-t_0 &:= t_{\mathit{start}} + T_{\mathit{interval, 0}} \\
+t_0 &:= t_{\mathit{start}} + T_{\mathit{interval}, 0} \\
 t_i &:= t_{\mathit{event}} + T_{\mathit{interval, i}} \qquad i = 1,2,3,{...}
 \end{align*}]
 
@@ -752,7 +752,7 @@ t_i &:= t_{\mathit{event}} + T_{\mathit{interval, i}} \qquad i = 1,2,3,{...}
 [cols="1,2"]
 |===
 
-|latexmath:[T_{\mathit{interval, 0}} \geq 0]
+|latexmath:[T_{\mathit{interval}, 0} \geq 0]
 |The time interval from latexmath:[t_{\mathit{start}}] to the first Clock tick.
 Must be retrieved using <<fmi3GetInterval>> in <<InitializationMode>>.
 
@@ -834,6 +834,10 @@ For restrictions on when to call which of the following functions for <<table-ov
 
 <<fmi3SetClock>> must not be called in Scheduled Execution, instead <<fmi3ActivateModelPartition>> must be called.
 
+_[The Clocks API function argument names <<intervals>>, <<shifts>>, <<counters>> and <<resolutions>> are chosen to match the naming used in link:https://specification.modelica.org/maint/3.6/synchronous-language-elements.html#clock-constructors[Modelica Clock Constructors]._
+_This commonality of naming does not imply any normative reference to the semantics of Modelica._
+_Mathematically speaking, the arguments <<counters>> and <<resolutions>> in the fraction variant of these functions serve as numerators and denominators of fractional representations of the corresponding floating-point number arguments of the decimal variant.]_
+
 [[fmi3SetInterval,`fmi3SetInterval`]]
 For <<table-overview-clocks,some Clock types>>, the interval must be set by the environment for the current time instant by the function <<fmi3SetIntervalDecimal>> or <<fmi3SetIntervalFraction>>.
 The values of the arguments <<intervals>>, <<shifts>>, and <<counters>> / <<resolutions>> refer to the unit of the <<independent>> variable.