From: stevenj <stevenj@alum.mit.edu>
Date: Sun, 9 Nov 2008 18:43:17 +0000 (-0500)
Subject: added internal nldrmd_minimize_ for use in subplex
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=a208f6a15c90abc4efcc717dc4acb63f01bd916c;p=nlopt.git

added internal nldrmd_minimize_ for use in subplex

darcs-hash:20081109184317-c8de0-d5f6b588c3e9ff822b50b221d3b9f432f5a748c8.gz
---

diff --git a/api/nlopt.c b/api/nlopt.c
index 2c08382..757b53f 100644
--- a/api/nlopt.c
+++ b/api/nlopt.c
@@ -494,7 +494,7 @@ static nlopt_result nlopt_minimize_(
               if (!scale) return NLOPT_OUT_OF_MEMORY;
               for (i = 0; i < n; ++i)
 		   scale[i] = initial_step(1, lb+i, ub+i, x+i);
-              ret = nldrmd_minimize(n, f,f_data, lb,ub,x, minf,scale,&stop,0.);
+              ret = nldrmd_minimize(n, f,f_data, lb,ub,x, minf,scale,&stop);
 	      free(scale);
 	      return ret;
 	 }
diff --git a/neldermead/neldermead.h b/neldermead/neldermead.h
index 9531d21..8ec8bfc 100644
--- a/neldermead/neldermead.h
+++ b/neldermead/neldermead.h
@@ -36,7 +36,15 @@ nlopt_result nldrmd_minimize(int n, nlopt_func f, void *f_data,
 			     double *x, /* in: initial guess, out: minimizer */
 			     double *minf,
 			     const double *xstep, /* initial step sizes */
-			     nlopt_stopping *stop, double psi);
+			     nlopt_stopping *stop);
+
+nlopt_result nldrmd_minimize_(int n, nlopt_func f, void *f_data,
+			      const double *lb, const double *ub, /* bounds */
+			      double *x,/* in: initial guess, out: minimizer */
+			      double *minf,
+			      const double *xstep, /* initial step sizes */
+			      nlopt_stopping *stop,
+			      double psi, double *scratch);
 
 #ifdef __cplusplus
 }  /* extern "C" */
diff --git a/neldermead/nldrmd.c b/neldermead/nldrmd.c
index b17adbf..336e47b 100644
--- a/neldermead/nldrmd.c
+++ b/neldermead/nldrmd.c
@@ -65,17 +65,27 @@ static void pin(int n, double *x, const double *lb, const double *ub) {
  if (nlopt_stop_evals(stop)) { ret=NLOPT_MAXEVAL_REACHED; goto done; }	  \
  if (nlopt_stop_time(stop)) { ret=NLOPT_MAXTIME_REACHED; goto done; }
 
-/* if psi > 0, then it *replaces* xtol and ftol in stop with the condition
+/* Internal version of nldrmd_minimize, intended to be used as
+   a subroutine for the subplex method.  Three differences compared
+   to nldrmd_minimize:
+
+   *minf should contain the value of f(x)  (so that we don't have to
+   re-evaluate f at the starting x).
+
+   if psi > 0, then it *replaces* xtol and ftol in stop with the condition
    that the simplex diameter |xl - xh| must be reduced by a factor of psi 
    ... this is for when nldrmd is used within the subplex method; for
-   ordinary termination tests, set psi = 0. */
-nlopt_result nldrmd_minimize(int n, nlopt_func f, void *f_data,
+   ordinary termination tests, set psi = 0. 
+
+   scratch should contain an array of length >= (n+1)*(n+1) + 2*n,
+   used as scratch workspace. */
+nlopt_result nldrmd_minimize_(int n, nlopt_func f, void *f_data,
 			     const double *lb, const double *ub, /* bounds */
 			     double *x, /* in: initial guess, out: minimizer */
 			     double *minf,
 			     const double *xstep, /* initial step sizes */
 			     nlopt_stopping *stop,
-			     double psi)
+			     double psi, double *scratch)
 {
      double *pts; /* (n+1) x (n+1) array of n+1 points plus function val [0] */
      double *c; /* centroid * n */
@@ -86,16 +96,14 @@ nlopt_result nldrmd_minimize(int n, nlopt_func f, void *f_data,
      nlopt_result ret = NLOPT_SUCCESS;
      double init_diam = 0;
 
-     pts = (double*) malloc(sizeof(double) * (n+1) * (n+1));
-     if (!pts) return NLOPT_OUT_OF_MEMORY;
-     c = (double*) malloc(sizeof(double) * n * 2);
-     if (!c) { free(pts); return NLOPT_OUT_OF_MEMORY; }
+     pts = scratch;
+     c = scratch + (n+1)*(n+1);
      xcur = c + n;
 
      /* initialize the simplex based on the starting xstep */
      memcpy(pts+1, x, sizeof(double)*n);
-     *minf = pts[0] = f(n, pts+1, NULL, f_data);
-     CHECK_EVAL(pts+1, pts[0]);
+     pts[0] = *minf;
+     if (*minf < stop->minf_max) { ret=NLOPT_MINF_MAX_REACHED; goto done; }
      for (i = 0; i < n; ++i) {
 	  double *pt = pts + (i+1)*(n+1);
 	  memcpy(pt+1, x, sizeof(double)*n);
@@ -226,7 +234,29 @@ nlopt_result nldrmd_minimize(int n, nlopt_func f, void *f_data,
      
 done:
      rb_tree_destroy(&t);
-     free(c);
-     free(pts);
+     return ret;
+}
+
+nlopt_result nldrmd_minimize(int n, nlopt_func f, void *f_data,
+			     const double *lb, const double *ub, /* bounds */
+			     double *x, /* in: initial guess, out: minimizer */
+			     double *minf,
+			     const double *xstep, /* initial step sizes */
+			     nlopt_stopping *stop)
+{
+     nlopt_result ret;
+     double *scratch = (double*) malloc(sizeof(double) * ((n+1)*(n+1) + 2*n));
+     if (!scratch) return NLOPT_OUT_OF_MEMORY;
+
+     *minf = f(n, x, NULL, f_data);
+     if (*minf < stop->minf_max) { ret=NLOPT_MINF_MAX_REACHED; goto done; }
+     stop->nevals++;
+     if (nlopt_stop_evals(stop)) { ret=NLOPT_MAXEVAL_REACHED; goto done; }
+     if (nlopt_stop_time(stop)) { ret=NLOPT_MAXTIME_REACHED; goto done; }
+
+     ret = nldrmd_minimize_(n, f, f_data, lb, ub, x, minf, xstep, stop,
+			    0.0, scratch);
+ done:
+     free(scratch);
      return ret;
 }