Add LMFIT source to repo

.. makes compilation easier and removes a dependency
   for what is effectively 2 C-source files.

.. additionally, getting the lmfit lib to compile
   on windows with cmake was frought with issues.

.. also fix a debug message left behind by previous
   commit.

lmfit/lmcurve.c

@@ -0,0 +1,52 @@
+/*
+ * Library:   lmfit (Levenberg-Marquardt least squares fitting)
+ *
+ * File:      lmcurve.c
+ *
+ * Contents:  Implements lmcurve, a simplified API for curve fitting
+ *            using the generic Levenberg-Marquardt routine lmmin.
+ *
+ * Copyright: Joachim Wuttke, Forschungszentrum Juelich GmbH (2004-2013)
+ *
+ * License:   see ../COPYING (FreeBSD)
+ *
+ * Homepage:  apps.jcns.fz-juelich.de/lmfit
+ *
+ * Note to programmers: Don't patch and fork, but copy and modify!
+ *   If you need to compute residues differently, then please do not patch
+ * lmcurve.h and lmcurve.c, but copy them, and create differently named
+ * versions of lmcurve_data_struct, lmcurve_evaluate, and lmcurve of your own.
+ */
+
+#include "lmmin.h"
+
+
+typedef struct {
+    const double *const t;
+    const double *const y;
+    double (*const g) (const double t, const double *par);
+} lmcurve_data_struct;
+
+
+void lmcurve_evaluate(
+    const double *const par, const int m_dat, const void *const data,
+    double *const fvec, int *const info)
+{
+    for (int i = 0; i < m_dat; i++ )
+        fvec[i] =
+            ((lmcurve_data_struct*)data)->y[i] -
+            ((lmcurve_data_struct*)data)->g(
+                ((lmcurve_data_struct*)data)->t[i], par );
+}
+
+
+void lmcurve(
+    const int n_par, double *const par, const int m_dat,
+    const double *const t, const double *const y,
+    double (*const g)(const double t, const double *const par),
+    const lm_control_struct *const control, lm_status_struct *const status)
+{
+    lmcurve_data_struct data = {t, y, g};
+    lmmin(n_par, par, m_dat, NULL, (const void *const) &data,
+          lmcurve_evaluate, control, status);
+}

lmfit/lmcurve.h

@@ -0,0 +1,45 @@
+/*
+ * Library:   lmfit (Levenberg-Marquardt least squares fitting)
+ *
+ * File:      lmcurve.h
+ *
+ * Contents:  Declares lmcurve, a simplified API for curve fitting
+ *            using the generic Levenberg-Marquardt routine lmmin.
+ *
+ * Copyright: Joachim Wuttke, Forschungszentrum Juelich GmbH (2004-2013)
+ *
+ * License:   see ../COPYING (FreeBSD)
+ *
+ * Homepage:  apps.jcns.fz-juelich.de/lmfit
+ *
+ * Note to programmers: Don't patch and fork, but copy and variate!
+ *   If you need to compute residues differently, then please do not patch
+ * lmcurve.h, but copy it to a differently named file, and change lmcurve()
+ * into a differently named function declaration, like we have done in
+ * lmcurve_tyd.h.
+ */
+
+#ifndef LMCURVE_H
+#define LMCURVE_H
+#undef __BEGIN_DECLS
+#undef __END_DECLS
+#ifdef __cplusplus
+#define __BEGIN_DECLS extern "C" {
+#define __END_DECLS }
+#else
+#define __BEGIN_DECLS /* empty */
+#define __END_DECLS   /* empty */
+#endif
+
+#include<lmstruct.h>
+
+__BEGIN_DECLS
+
+void lmcurve(
+    const int n_par, double* par, const int m_dat,
+    const double* t, const double* y,
+    double (*g)(const double t, const double* par),
+    const lm_control_struct* control, lm_status_struct* status);
+
+__END_DECLS
+#endif /* LMCURVE_H */

lmfit/lmcurve_tyd.h

@@ -0,0 +1,39 @@
+/*
+ * Library:   lmfit (Levenberg-Marquardt least squares fitting)
+ *
+ * File:      lmcurve_tyd.h
+ *
+ * Contents:  Declares lmcurve_tyd(), a variant of lmcurve() that weighs
+ *            data points y(t) with the inverse of the standard deviations dy.
+ *
+ * Copyright: Joachim Wuttke, Forschungszentrum Juelich GmbH (2004-2013)
+ *
+ * License:   see ../COPYING (FreeBSD)
+ *
+ * Homepage:  apps.jcns.fz-juelich.de/lmfit
+ */
+
+#ifndef LMCURVETYD_H
+#define LMCURVETYD_H
+#undef __BEGIN_DECLS
+#undef __END_DECLS
+#ifdef __cplusplus
+#define __BEGIN_DECLS extern "C" {
+#define __END_DECLS }
+#else
+#define __BEGIN_DECLS /* empty */
+#define __END_DECLS   /* empty */
+#endif
+
+#include <lmstruct.h>
+
+__BEGIN_DECLS
+
+void lmcurve_tyd(
+    const int n_par, double* par, const int m_dat,
+    const double* t, const double* y, const double* dy,
+    double (*f)(double t, const double* par),
+    const lm_control_struct* control, lm_status_struct* status);
+
+__END_DECLS
+#endif /* LMCURVETYD_H */