From e208b972e38eff84c0287ae6bf32db7b42cce0f6 Mon Sep 17 00:00:00 2001
From: Kristof Bastiaensen <kristof@vleeuwen.org>
Date: Fri, 16 Aug 2013 14:16:32 +0200
Subject: Added onedimensional minimization.

---
 lib/Numeric/GSL/Minimization.hs | 34 ++++++++++++++++++++++++++
 lib/Numeric/GSL/gsl-aux.c       | 54 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)

(limited to 'lib')

diff --git a/lib/Numeric/GSL/Minimization.hs b/lib/Numeric/GSL/Minimization.hs
index af85135..7ccca81 100644
--- a/lib/Numeric/GSL/Minimization.hs
+++ b/lib/Numeric/GSL/Minimization.hs
@@ -53,6 +53,7 @@ The nmsimplex2 version is a new O(N) implementation of the earlier O(N^2) nmsimp
 module Numeric.GSL.Minimization (
     minimize, minimizeV, MinimizeMethod(..),
     minimizeD, minimizeVD, MinimizeMethodD(..),
+    uniMinimize, UniMinimizeMethod(..),
 
     minimizeNMSimplex,
     minimizeConjugateGradient,
@@ -81,6 +82,39 @@ minimizeVectorBFGS2 step tol eps maxit f g xi = minimizeD VectorBFGS2 eps maxit
 
 -------------------------------------------------------------------------
 
+data UniMinimizeMethod = GoldenSection
+                       | BrentMini
+                       | QuadGolden
+                       deriving (Enum, Eq, Show, Bounded)
+
+-- | Onedimensional minimization.
+
+uniMinimize :: UniMinimizeMethod -- ^ The method used.
+        -> Double               -- ^ desired precision of the solution
+        -> Int                  -- ^ maximum number of iterations allowed
+        -> (Double -> Double)   -- ^ function to minimize
+        -> Double               -- ^ guess for the location of the minimum
+        -> Double               -- ^ lower bound of search interval
+        -> Double               -- ^ upper bound of search interval
+        -> (Double, Matrix Double) -- ^ solution and optimization path
+
+uniMinimize method epsrel maxit fun xmin xl xu = uniMinimizeGen (fi (fromEnum method)) fun xmin xl xu epsrel maxit
+
+uniMinimizeGen m f xmin xl xu epsrel maxit = unsafePerformIO $ do
+    fp <- mkDoublefun f
+    rawpath <- createMIO maxit 4
+                         (c_uniMinize m fp epsrel (fi maxit) xmin xl xu)
+                         "uniMinimize"
+    let it = round (rawpath @@> (maxit-1,0))
+        path = takeRows it rawpath
+        [sol] = toLists $ dropRows (it-1) path
+    freeHaskellFunPtr fp
+    return (sol !! 1, path)
+
+
+foreign import ccall safe "uniMinimize"
+    c_uniMinize:: CInt -> FunPtr (Double -> Double) -> Double -> CInt -> Double -> Double -> Double -> TM
+
 data MinimizeMethod = NMSimplex
                     | NMSimplex2
                     deriving (Enum,Eq,Show,Bounded)
diff --git a/lib/Numeric/GSL/gsl-aux.c b/lib/Numeric/GSL/gsl-aux.c
index e727c91..58bccb3 100644
--- a/lib/Numeric/GSL/gsl-aux.c
+++ b/lib/Numeric/GSL/gsl-aux.c
@@ -29,6 +29,7 @@
 #include <gsl/gsl_poly.h>
 #include <gsl/gsl_multimin.h>
 #include <gsl/gsl_multiroots.h>
+#include <gsl/gsl_min.h>
 #include <gsl/gsl_complex_math.h>
 #include <gsl/gsl_rng.h>
 #include <gsl/gsl_randist.h>
@@ -892,6 +893,59 @@ double only_f_aux_min(const gsl_vector*x, void *pars) {
     return res;
 }
 
+double only_f_aux_root(double x, void *pars);
+int uniMinimize(int method, double f(double),
+		double epsrel, int maxit, double min,
+		double xl, double xu, RMAT(sol)) {
+   REQUIRES(solr == maxit && solc == 4,BAD_SIZE);
+   DEBUGMSG("minimize_only_f");
+   gsl_function my_func;
+   my_func.function = only_f_aux_root;
+   my_func.params = f;
+   size_t iter = 0;
+   int status;
+   const gsl_min_fminimizer_type *T;
+   gsl_min_fminimizer *s;
+   // Starting point
+   switch(method) {
+     case 0 : {T = gsl_min_fminimizer_goldensection; break; }
+     case 1 : {T = gsl_min_fminimizer_brent; break; }
+     case 2 : {T = gsl_min_fminimizer_quad_golden; break; }
+     default: ERROR(BAD_CODE);
+   }
+   s = gsl_min_fminimizer_alloc (T);
+   gsl_min_fminimizer_set (s, &my_func, min, xl, xu);
+   do {
+       double current_min, current_lo, current_hi;
+       status = gsl_min_fminimizer_iterate (s);
+       current_min = gsl_min_fminimizer_x_minimum (s);
+       current_lo = gsl_min_fminimizer_x_lower (s);
+       current_hi = gsl_min_fminimizer_x_upper (s);
+       solp[iter*solc] = iter + 1;
+       solp[iter*solc+1] = current_min;
+       solp[iter*solc+2] = current_lo;
+       solp[iter*solc+3] = current_hi;
+       iter++;
+       if (status)   /* check if solver is stuck */
+	  break;
+       
+       status =
+	 gsl_min_test_interval (current_lo, current_hi, 0, epsrel);
+   }
+   while (status == GSL_CONTINUE && iter < maxit);
+   int i;
+   for (i=iter; i<solr; i++) {
+       solp[i*solc+0] = iter;
+       solp[i*solc+1]=0.;
+       solp[i*solc+2]=0.;
+       solp[i*solc+3]=0.;
+   }
+   gsl_min_fminimizer_free(s);
+   OK
+}
+
+   
+
 // this version returns info about intermediate steps
 int minimize(int method, double f(int, double*), double tolsize, int maxit, 
                  KRVEC(xi), KRVEC(sz), RMAT(sol)) {
-- 
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