Add initial value setting API for solver and optimize contexts and update related function signatures

Author: NikolajBjorner

RELEASE_NOTES.md

@@ -15,7 +15,10 @@ Version 4.13.1
 - single-sample cell projection in nlsat was designed by Haokun Li and Bican Xia. 
 - using simple-checker together with and variable ordering supported by qfnra_tactic was developed by Mengyu Zhao (Linxi) and Shaowei Cai.
 
-   The projection is described in paper by Haokun Li and Bican Xia,   [Solving Satisfiability of Polynomial Formulas By Sample - Cell Projection](https://arxiv.org/abs/2003.00409). The code ported from https://github.com./hybridSMT/hybridSMT.git 
+   The projection is described in paper by Haokun Li and Bican Xia,   [Solving Satisfiability of Polynomial Formulas By Sample - Cell Projection](https://arxiv.org/abs/2003.00409). The code ported from https://github.com./hybridSMT/hybridSMT.git
+
+- Add API for providing hints for the solver/optimize contexts for which initial values to attempt to use for variables.
+ The new API function are Z3_solver_set_initial_value and Z3_optimize_set_initial_value, respectively. Supply these functions with a Boolean or numeric variable, and a value. The solver will then attempt to use these values in the initial phase of search. The feature is aimed at resolving nearly similar problems, or problems with a predicted model and the intent is that restarting the solver based on a near solution can avoid prune the space of constraints that are initially infeasible. 
 
 Version 4.13.0
 ==============

src/api/z3_api.h

@@ -7250,7 +7250,7 @@ extern "C" {
        def_API('Z3_solver_set_initial_value', VOID, (_in(CONTEXT), _in(SOLVER), _in(AST), _in(AST)))
      */
 
-    void Z3_API Z3_solver_set_initial_value(Z3_context c, Z3_solver s, Z3_ast var, Z3_ast value);
+    void Z3_API Z3_solver_set_initial_value(Z3_context c, Z3_solver s, Z3_ast v, Z3_ast val);
 
 
     /**

src/api/z3_optimization.h

@@ -149,7 +149,7 @@ extern "C" {
        def_API('Z3_optimize_set_initial_value', VOID, (_in(CONTEXT), _in(OPTIMIZE), _in(AST), _in(AST)))
      */
 
-    void Z3_API Z3_optimize_set_initial_value(Z3_context c, Z3_optimize o, Z3_ast var, Z3_ast value);
+    void Z3_API Z3_optimize_set_initial_value(Z3_context c, Z3_optimize o, Z3_ast v, Z3_ast val);
 
     /**
        \brief Check consistency and produce optimal values.