pst-ode (24nov22)

git-svn-id: svn://tug.org/texlive/trunk@65096 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 18 insertions, 6 deletions

diff --git a/Master/texmf-dist/tex/generic/pst-ode/pst-ode.tex b/Master/texmf-dist/tex/generic/pst-ode/pst-ode.tex
index 7cb0e895733..3ab38399c38 100644
--- a/Master/texmf-dist/tex/generic/pst-ode/pst-ode.tex
+++ b/Master/texmf-dist/tex/generic/pst-ode/pst-ode.tex
@@ -12,8 +12,8 @@
 %% ODEs using the Runge-Kutta-Fehlberg (RKF45) method with automatic
 %% step size adjustment
 %%
-\def\fileversion{0.17}
-\def\filedate{2022/05/14}
+\def\fileversion{0.18}
+\def\filedate{2022/11/24}
 
 \csname PSTODELoaded\endcsname
 \let\PSTODELoaded\endinput
@@ -64,6 +64,8 @@
 %   * varsteptol   relative tolerance for step size adjustment
 %   * dt0          first tentative integration step size, overrides output step
 %                  size (#4-#3)/(#5-1) used as default value
+%   * rk4          instead of RKF45, use 4th-order classical Runge-Kutta between
+%                  output points (without adaptive step size)
 %
 % arguments:
 %
@@ -87,6 +89,7 @@
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 \define@boolkey[psset]{pst-ode}[PstODE@]{append}[true]{}%
 \define@boolkey[psset]{pst-ode}[PstODE@]{saveData}[true]{}%
+\define@boolkey[psset]{pst-ode}[PstODE@]{rk4}[true]{}%
 \define@boolkey[psset]{pst-ode}[PstODE@]{algebraicT}[true]{}%
 \define@boolkey[psset]{pst-ode}[PstODE@]{algebraicN}[true]{}%
 \define@boolkey[psset]{pst-ode}[PstODE@]{algebraicIC}[true]{}%
@@ -126,6 +129,9 @@
     \fi
     /ode@tol \ode@varsteptol\space def % rel. tolerance for step size adjustment
     %process arguments
+    /rk4
+      \expandafter\csname ifPstODE@rk4\endcsname true\else false\fi\space
+    def
     \ifPstODE@saveData /statefile (#1.dat) (\filemode) file def \fi
     \ifPstODE@algebraicT
       tx@Dict begin (\expandafter\ode@zapspace\ode@ta\@nil)
@@ -175,10 +181,14 @@
         ode@dict ode@laststate /x exch def /y x def /t tcur def end
         tx@Dict begin ode@dict ode@fmtrpn end end
       } bind def
-    \else /formatoutput {[#2] assembleresult} def \fi%
+    \else /formatoutput {[#2] assembleresult} def \fi
     %perform ode integration
-    (\string\n pstODEsolve (RKF45),\string\n) odeprint
-    (-/+ failed/successful step, "o" output step, "!" step size underflow (stop):\string\n) odeprint
+    rk4 {
+      (\string\n pstODEsolve (RK4),) odeprint ( "o" output step:\string\n) odeprint
+    }{
+      (\string\n pstODEsolve (RKF45),\string\n) odeprint
+      (-/+ failed/successful step, "o" output step, "!" step size underflow (stop):\string\n) odeprint
+    } ifelse
     ode@dict
       /tcur tStart def % current parameter t value
       /outStepCnt 1 def % output step counter
@@ -193,6 +203,8 @@
         \ode@dtInit\space 0 eq
           {/ddt dt def}{/ddt \ode@dtInit\space def} ifelse
       \fi
+      % for RK4, use output step size
+      rk4 {/ddt dt def} if
     end
     \ifPstODE@append\else
       [
@@ -261,7 +273,7 @@
 
 \psset[pst-ode]{append=false,saveData=false,algebraicIC=false,algebraicT=false,
   algebraicN=false,silent=false,varsteptol=1e-6,algebraicOutputFormat=false,
-  algebraicAll=false,dt0=0
+  algebraicAll=false,dt0=0,rk4=false
 }
 \psset{algebraic=false}
 \catcode`\@=\PstAtCode\relax