added odeSolve

3 files changed, 201 insertions, 1 deletions

diff --git a/lib/Numeric/GSL/Internal.hs b/lib/Numeric/GSL/Internal.hs
index 834dfc2..37bcc1b 100644
--- a/lib/Numeric/GSL/Internal.hs
+++ b/lib/Numeric/GSL/Internal.hs
@@ -30,6 +30,9 @@ foreign import ccall "wrapper"
 foreign import ccall "wrapper"
     mkVecVecfun :: TVV -> IO (FunPtr TVV)
 
+foreign import ccall "wrapper"
+    mkDoubleVecVecfun :: (Double -> TVV) -> IO (FunPtr (Double -> TVV))
+
 aux_vTov :: (Vector Double -> Vector Double) -> TVV
 aux_vTov f n p nr r = g where
     V {fptr = pr} = f x
@@ -43,6 +46,9 @@ aux_vTov f n p nr r = g where
 foreign import ccall "wrapper"
     mkVecMatfun :: TVM -> IO (FunPtr TVM)
 
+foreign import ccall "wrapper"
+    mkDoubleVecMatfun :: (Double -> TVM) -> IO (FunPtr (Double -> TVM))
+
 aux_vTom :: (Vector Double -> Matrix Double) -> TVM
 aux_vTom f n p rr cr r = g where
     V {fptr = pr} = flatten $ f x
diff --git a/lib/Numeric/GSL/ODE.hs b/lib/Numeric/GSL/ODE.hs
new file mode 100644
index 0000000..3450b91
--- /dev/null
+++ b/lib/Numeric/GSL/ODE.hs
@@ -0,0 +1,107 @@
+{- |
+Module      :  Numeric.GSL.ODE
+Copyright   :  (c) Alberto Ruiz 2010
+License     :  GPL
+
+Maintainer  :  Alberto Ruiz (aruiz at um dot es)
+Stability   :  provisional
+Portability :  uses ffi
+
+Solution of ordinary differential equation (ODE) initial value problems.
+
+<http://www.gnu.org/software/gsl/manual/html_node/Ordinary-Differential-Equations.html>
+
+A simple example:
+
+@import Numeric.GSL
+import Numeric.LinearAlgebra
+import Graphics.Plot
+
+xdot t [x,v] = [v, -0.95*x - 0.1*v]
+
+ts = linspace 100 (0,20)
+
+sol = odeSolve xdot [10,0] ts
+
+main = mplot (ts : toColumns sol)@
+
+-}
+-----------------------------------------------------------------------------
+
+module Numeric.GSL.ODE (
+    odeSolve, odeSolveV, ODEMethod(..)
+) where
+
+import Data.Packed.Internal
+import Data.Packed.Matrix
+import Foreign
+import Foreign.C.Types(CInt)
+import Numeric.GSL.Internal
+
+-------------------------------------------------------------------------
+
+-- | Stepping functions
+data ODEMethod = RK2 -- ^ Embedded Runge-Kutta (2, 3) method.
+               | RK4 -- ^ 4th order (classical) Runge-Kutta. The error estimate is obtained by halving the step-size. For more efficient estimate of the error, use 'RKf45'.
+               | RKf45 -- ^ Embedded Runge-Kutta-Fehlberg (4, 5) method. This method is a good general-purpose integrator.
+               | RKck -- ^ Embedded Runge-Kutta Cash-Karp (4, 5) method.
+               | RK8pd -- ^ Embedded Runge-Kutta Prince-Dormand (8,9) method.
+               | RK2imp -- ^ Implicit 2nd order Runge-Kutta at Gaussian points.
+               | RK4imp -- ^ Implicit 4th order Runge-Kutta at Gaussian points.
+               | BSimp -- ^ Implicit Bulirsch-Stoer method of Bader and Deuflhard. This algorithm requires the Jacobian.
+               | Gear1 -- ^ M=1 implicit Gear method.
+               | Gear2 -- ^ M=2 implicit Gear method.
+               deriving (Enum,Eq,Show,Bounded)
+
+-- | A version of 'odeSolveV' with reasonable default parameters and system of equations defined using lists.
+odeSolve
+    :: (Double -> [Double] -> [Double])        -- ^ xdot(t,x)
+    -> [Double]        -- ^ initial conditions
+    -> Vector Double   -- ^ desired solution times
+    -> Matrix Double   -- ^ solution
+odeSolve xdot xi ts = odeSolveV RKf45 hi epsAbs epsRel (l2v xdot) Nothing (fromList xi) ts
+    where hi = (ts@>1 - ts@>0)/100
+          epsAbs = 1.49012e-08
+          epsRel = 1.49012e-08
+          l2v f = \t -> fromList  . f t . toList
+          l2m f = \t -> fromLists . f t . toList
+
+-- | Evolution of the system with adaptive step-size control.
+odeSolveV
+    :: ODEMethod
+    -> Double -- ^ initial step size
+    -> Double -- ^ absolute tolerance for the state vector
+    -> Double -- ^ relative tolerance for the state vector
+    -> (Double -> Vector Double -> Vector Double)   -- ^ xdot(t,x)
+    -> Maybe (Double -> Vector Double -> Matrix Double)   -- ^ optional jacobian
+    -> Vector Double     -- ^ initial conditions
+    -> Vector Double     -- ^ desired solution times
+    -> Matrix Double     -- ^ solution
+odeSolveV method h epsAbs epsRel f mbjac xiv ts = unsafePerformIO $ do
+    let n   = dim xiv
+    fp <- mkDoubleVecVecfun (\t -> aux_vTov (checkdim1 n . f t))
+    jp <- case mbjac of
+        Just jac -> mkDoubleVecMatfun (\t -> aux_vTom (checkdim2 n . jac t))
+        Nothing  -> return nullFunPtr
+    sol <- withVector xiv $ \xiv' ->
+            withVector ts $ \ts' ->
+             createMIO (dim ts) n
+              (ode_c (fi (fromEnum method)) h epsAbs epsRel fp jp // xiv' // ts' )
+              "ode"
+    freeHaskellFunPtr fp
+    return sol
+
+foreign import ccall "ode"
+    ode_c :: CInt -> Double -> Double -> Double -> FunPtr (Double -> TVV) -> FunPtr (Double -> TVM) -> TVVM
+
+-------------------------------------------------------
+
+checkdim1 n v
+    | dim v == n = v
+    | otherwise = error $ "Error: "++ show n
+                        ++ " components expected in the result of the function supplied to odeSolve"
+
+checkdim2 n m
+    | rows m == n && cols m == n = m
+    | otherwise = error $ "Error: "++ show n ++ "x" ++ show n
+                        ++ " Jacobian expected in odeSolve"
diff --git a/lib/Numeric/GSL/gsl-aux.c b/lib/Numeric/GSL/gsl-aux.c
index 0c71ca1..0fcde1c 100644
--- a/lib/Numeric/GSL/gsl-aux.c
+++ b/lib/Numeric/GSL/gsl-aux.c
@@ -22,6 +22,7 @@
 #include <gsl/gsl_complex_math.h>
 #include <gsl/gsl_rng.h>
 #include <gsl/gsl_randist.h>
+#include <gsl/gsl_odeiv.h>
 #include <string.h>
 #include <stdio.h>
 
@@ -507,7 +508,7 @@ double f_aux_min(const gsl_vector*x, void *pars) {
 
 
 void df_aux_min(const gsl_vector * x, void * pars, gsl_vector * g) {
-    Tfdf * fdf = ((Tfdf*) pars);  
+    Tfdf * fdf = ((Tfdf*) pars);
     double* p = (double*)calloc(x->size,sizeof(double));
     double* q = (double*)calloc(g->size,sizeof(double));
     int k;
@@ -797,3 +798,89 @@ int random_vector(int seed, int code, RVEC(r)) {
     }
 }
 #undef RAN
+
+//////////////////////////////////////////////////////
+//                        ODE
+
+typedef struct {int n; int (*f)(double,int, const double*, int, double *); int (*j)(double,int, const double*, int, int, double*);} Tode;
+
+int odefunc (double t, const double y[], double f[], void *params) { 
+    Tode * P = (Tode*) params;
+    (P->f)(t,P->n,y,P->n,f);
+    return GSL_SUCCESS;
+}
+
+int odejac (double t, const double y[], double *dfdy, double dfdt[], void *params) {
+     Tode * P = ((Tode*) params);
+     (P->j)(t,P->n,y,P->n,P->n,dfdy);
+     int j;
+     for (j=0; j< P->n; j++)
+        dfdt[j] = 0.0;
+     return GSL_SUCCESS;
+}
+
+
+int ode(int method, double h, double eps_abs, double eps_rel,
+        int f(double, int, const double*, int, double*),
+        int jac(double, int, const double*, int, int, double*),
+        KRVEC(xi), KRVEC(ts), RMAT(sol)) {
+
+    const gsl_odeiv_step_type * T;
+
+    switch(method) {
+        case 0 : {T = gsl_odeiv_step_rk2; break; }
+        case 1 : {T = gsl_odeiv_step_rk4; break; }
+        case 2 : {T = gsl_odeiv_step_rkf45; break; }
+        case 3 : {T = gsl_odeiv_step_rkck; break; }
+        case 4 : {T = gsl_odeiv_step_rk8pd; break; }
+        case 5 : {T = gsl_odeiv_step_rk2imp; break; }
+        case 6 : {T = gsl_odeiv_step_rk4imp; break; }
+        case 7 : {T = gsl_odeiv_step_bsimp; break; }
+        case 8 : {T = gsl_odeiv_step_gear1; break; }
+        case 9 : {T = gsl_odeiv_step_gear2; break; }
+        default: ERROR(BAD_CODE);
+    }
+
+
+    gsl_odeiv_step * s = gsl_odeiv_step_alloc (T, xin);
+    gsl_odeiv_control * c = gsl_odeiv_control_y_new (eps_abs, eps_rel);
+    gsl_odeiv_evolve * e = gsl_odeiv_evolve_alloc (xin);
+
+    Tode P;
+    P.f = f;
+    P.j = jac;
+    P.n = xin;
+
+    gsl_odeiv_system sys = {odefunc, odejac, xin, &P};
+
+    double t = tsp[0];
+
+    double* y = (double*)calloc(xin,sizeof(double));
+    int i,j;
+    for(i=0; i< xin; i++) {
+        y[i] = xip[i];
+        solp[i] = xip[i];
+    }
+
+       for (i = 1; i < tsn ; i++)
+         {
+           double ti = tsp[i];
+           while (t < ti)
+             {
+               gsl_odeiv_evolve_apply (e, c, s,
+                                       &sys,
+                                       &t, ti, &h,
+                                       y);
+               // if (h < hmin) h = hmin;
+             }
+           for(j=0; j<xin; j++) {
+               solp[i*xin + j] = y[j];
+           }
+         }
+
+    free(y);
+    gsl_odeiv_evolve_free (e);
+    gsl_odeiv_control_free (c);
+    gsl_odeiv_step_free (s);
+    return 0;
+}