class for linearly interpolated functions

lib/TabFunction.cpp

@@ -0,0 +1,84 @@
+/*
+ * TabFunction.cpp, part of LatAnalyze 3
+ *
+ * Copyright (C) 2013 - 2014 Antonin Portelli
+ *
+ * LatAnalyze 3 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LatAnalyze 3 is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LatAnalyze 3.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <LatAnalyze/TabFunction.hpp>
+#include <LatAnalyze/includes.hpp>
+
+using namespace std;
+using namespace Latan;
+
+/******************************************************************************
+ *                       TabFunction implementation                           *
+ ******************************************************************************/
+// constructors ////////////////////////////////////////////////////////////////
+TabFunction::TabFunction(void)
+: DoubleFunction(1)
+{}
+
+TabFunction::TabFunction(const DVec &x, const DVec &y)
+: TabFunction()
+{
+    setData(x, y);
+}
+
+TabFunction::TabFunction(const XYStatData &data, const Index i, const Index j)
+: TabFunction()
+{
+    setData(data, i, j);
+}
+
+// access //////////////////////////////////////////////////////////////////////
+void TabFunction::setData(const DVec &x, const DVec &y)
+{
+    if (x.size() != y.size())
+    {
+        LATAN_ERROR(Size, "tabulated function x/y data size mismatch");
+    }
+    FOR_VEC(x, i)
+    {
+        value_[x(i)] = y(i);
+    }
+}
+
+void TabFunction::setData(const XYStatData &data, const Index i, const Index j)
+{
+    setData(data.x(i), data.y(j));
+}
+
+// function call ///////////////////////////////////////////////////////////////
+double TabFunction::operator()(const double *arg) const
+{
+    double x = arg[0], x_a, x_b, y_a, y_b;
+    
+    if ((x < value_.begin()->first)||(x >= value_.rbegin()->first))
+    {
+        LATAN_ERROR(Range, "tabulated function variable out of range");
+    }
+    
+    auto i    = value_.equal_range(x);
+    auto low  = (x == i.first->first) ? i.first : prev(i.first);
+    auto high = i.second;
+    
+    x_a = low->first;
+    x_b = high->first;
+    y_a = low->second;
+    y_b = high->second;
+    
+    return y_a + (x - x_a)*(y_b - y_a)/(x_b - x_a);
+}

lib/TabFunction.hpp

@@ -0,0 +1,55 @@
+/*
+ * TabFunction.hpp, part of LatAnalyze 3
+ *
+ * Copyright (C) 2013 - 2014 Antonin Portelli
+ *
+ * LatAnalyze 3 is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LatAnalyze 3 is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LatAnalyze 3.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef Latan_TabFunction_hpp_
+#define Latan_TabFunction_hpp_
+
+#include <map>
+#include <LatAnalyze/Global.hpp>
+#include <LatAnalyze/Function.hpp>
+#include <LatAnalyze/XYStatData.hpp>
+
+BEGIN_NAMESPACE
+
+/******************************************************************************
+ *                      tabulated function: 1D only                           *
+ ******************************************************************************/
+
+class TabFunction: public DoubleFunction
+{
+public:
+    // constructors
+    TabFunction(void);
+    TabFunction(const DVec &x, const DVec &y);
+    TabFunction(const XYStatData &data, const Index i = 0, const Index j = 0);
+    // destructor
+    virtual ~TabFunction(void) = default;
+    // access
+    void setData(const DVec &x, const DVec &y);
+    void setData(const XYStatData &data, const Index i = 0, const Index j = 0);
+    // function call
+    using DoubleFunction::operator();
+    virtual double operator()(const double *arg) const;
+private:
+    std::map<double, double> value_;
+};
+
+END_NAMESPACE
+
+#endif // Latan_TabFunction_hpp_