reintegration of LatCore & folder restructuration

lib/Functional/TabFunction.cpp

@@ -0,0 +1,164 @@
+/*
+ * TabFunction.cpp, part of LatAnalyze 3
+ *
+ * Copyright (C) 2013 - 2016 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/Functional/TabFunction.hpp>
+#include <LatAnalyze/includes.hpp>
+
+using namespace std;
+using namespace Latan;
+
+/******************************************************************************
+ *                       TabFunction implementation                           *
+ ******************************************************************************/
+// constructors ////////////////////////////////////////////////////////////////
+TabFunction::TabFunction(const DVec &x, const DVec &y,
+                         const InterpType interpType)
+{
+    setData(x, y);
+    setInterpolationType(interpType);
+}
+
+// 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::setInterpolationType(const InterpType interpType)
+{
+    interpType_ = interpType;
+}
+
+// function call ///////////////////////////////////////////////////////////////
+double TabFunction::operator()(const double *arg) const
+{
+    double result = 0.0, x = arg[0];
+
+
+    if ((x < value_.begin()->first) or (x >= value_.rbegin()->first)) {
+        LATAN_ERROR(Range, "tabulated function variable out of range "
+                               "(x= " + strFrom(x) + " not in ["
+                           + strFrom(value_.begin()->first) + ", "
+                           + strFrom(value_.rbegin()->first) + "])");
+    }
+
+    auto i = value_.equal_range(x);
+    auto low = (x == i.first->first) ? i.first : prev(i.first);
+    auto high = i.second;
+
+    switch (interpType_) {
+        case InterpType::LINEAR: {
+            double x_a, x_b, y_a, y_b;
+
+            x_a = low->first;
+            x_b = high->first;
+            y_a = low->second;
+            y_b = high->second;
+            result = y_a + (x - x_a) * (y_b - y_a) / (x_b - x_a);
+            break;
+        }
+        case InterpType::NEAREST: {
+            result = nearest(x)->second;
+            break;
+        }
+        case InterpType::QUADRATIC: {
+            double xs[3], ys[3], ds[3], d01, d02, d12;
+            auto it = nearest(x);
+            if (it == value_.begin()) {
+                it = next(it);
+            }
+            else if (it == prev(value_.end())) {
+                it = prev(it);
+            }
+            xs[0] = prev(it)->first;
+            ys[0] = prev(it)->second;
+            xs[1] = it->first;
+            ys[1] = it->second;
+            xs[2] = next(it)->first;
+            ys[2] = next(it)->second;
+            ds[0] = x - xs[0];
+            ds[1] = x - xs[1];
+            ds[2] = x - xs[2];
+            d01   = xs[0] - xs[1];
+            d02   = xs[0] - xs[2];
+            d12   = xs[1] - xs[2];
+
+            // Lagrange polynomial coefficient computation
+            result = ds[1]/d01*ds[2]/d02*ys[0]
+                     -ds[0]/d01*ds[2]/d12*ys[1]
+                     +ds[0]/d02*ds[1]/d12*ys[2];
+            break;
+        }
+        default:
+            int intType = static_cast<int>(interpType_);
+            LATAN_ERROR(Implementation, "unsupported interpolation type in "
+                                        "tabulated function: "
+                                        + strFrom(intType));
+    }
+    
+    return result;
+}
+
+// DoubleFunction factory //////////////////////////////////////////////////////
+DoubleFunction TabFunction::makeFunction(const bool makeHardCopy) const
+{
+    DoubleFunction res;
+
+    if (makeHardCopy)
+    {
+        TabFunction copy(*this);
+
+        res.setFunction([copy](const double *x){return copy(x);}, 1);
+    }
+    else
+    {
+        res.setFunction([this](const double *x){return (*this)(x);}, 1);
+    }
+
+    return res;
+}
+
+DoubleFunction Latan::interpolate(const DVec &x, const DVec &y,
+                                  const InterpType interpType)
+{
+    return TabFunction(x, y, interpType).makeFunction();
+}
+
+map<double, double>::const_iterator TabFunction::nearest(const double x) const
+{
+    map<double, double>::const_iterator ret;
+    auto i = value_.equal_range(x);
+    auto low = (x == i.first->first) ? i.first : prev(i.first);
+    auto high = i.second;
+    if (fabs(high->first - x) < fabs(low->first - x)) {
+        ret = high;
+    }
+    else {
+        ret = low;
+    }
+
+    return ret;
+}