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--- libnum:classes:gear [2026/03/04 15:33] – abc
+++ libnum:classes:gear [2026/03/29 13:53] (current) – abc
@@ Line 1: / Line 1: @@
 ====== Libnum Classes ======
-====== Integration of Systems of Linear Differential Equations. \\ Gear's method ======
+===== Gear Integration Method =====
+===== class Gear; =====
+Namespace //NumericMethods//
-  namespace NumericMethods
+See: ''gear.h'', ''gear.asst.h'', ''gear.proc.h'' and ''gear.output.h'' files.
-See: ''gear.h'' and ''gear.asst.h'' files.
-class [[#Gear|Gear]]; \\
 class [[#GearUserProc|GearUserProc]]; \\
 struct [[#GearEngineContext|GearEngineContext]]; \\
@@ Line 16: / Line 15: @@
 class [[#GearAllocator|GearAllocator]]; \\
-===== Gear =====
   class Gear
   {
@@ Line 23: / Line 21: @@
    ~Gear();
     void set(int n, GearUserProc* derFunc, GearUserProc* jacFunc);
-    void setCallback(GearEngineCallback& f) { callback = &f;}
+    void setCallback(GearEngineCallback& f);
     Message solve(const double t_begin, const double t_end, const double* y0);
     GearEngineContext engineContext;
@@ Line 118: / Line 116: @@
   RHMAX = 1;
 See Gear Algorithm for details.
+===== Gear Output =====
+The Output is implemented via //GearEngineCallback// interface. The most GearEngine data are available via //GearEngineContext// object, passed to its method ''call(const GearEngineContext& context)''.
+The //libnum// library includes the following two classes for general useage: //GearPrintToStream// and //GearPrintTable//. Both interfaces use user-declared output stream for their target (see [[https://en.cppreference.com/w/cpp/io/basic_ostream.html|STL manual]]). It can be:
+  * standard C output stream stdout (//std::cout//)
+  * string buffer (//std::stringstream//)
+  * file (//std::ofstream//)
+  * and the like
+The //GearPrintToStream// interface enables us to output //time/values// data of each integration point into the output stream, //GearPrintTable// outputs tabulated data (it uses interpolation to calculate variables' values for user declared output time-step). One can set a format of double value presentation, ''std::format'' syntax being supposed, for example "{:8.5f}\t".
+  class GearPrintToStream : public GearEngineCallback
+  {
+  public:
+    GearPrintToStream(std::ostream& target, const char* format = "{} ");
+    virtual bool call(const GearEngineContext&) override;
+    void setFormat(const char* format);
+  };
+  class GearPrintTable : public GearPrintToStream
+  {
+  public:
+    GearPrintTable(std::ostream& target, double output_step, const char* format = "{} ");
+    virtual bool call(const GearEngineContext&) override;
+    void reset();
+  };
 ----
-[ [[.:|Libnum classes]] ] [ [[..:examples:gear|Example of usage]] ]
+[ [[.:|Libnum classes]] ] [ [[..:examples:gear|Examples of usage]] ]