1- // -*- C++ -*-
2- // -*- coding: utf-8 -*-
3- //
4- // Source Author: Bryan Riel
5- // Copyright 2017-2018
6- //
7-
81#if !defined(ISCE_CORE_LUT1D_ICC)
92#error "LUT1d.icc is an implementation detail of class LUT1d"
103#endif
114
125#include <pyre/journal.h>
136
14- // Constructor from an LUT2d (values averaged in y-direction)
15- /* * @param[in] lut2d LUT2d to copy data from */
16- template <typename T>
17- isce3::core::LUT1d<T>::
18- LUT1d (const isce3::core::LUT2d<T> & lut2d) {
19-
20- // Check if LUT2d has actual data; if not, just store reference value
21- if (!lut2d.haveData ()) {
22- _haveData = false ;
23- _refValue = lut2d.refValue ();
24- return ;
25- }
26-
27- // Get a reference to the LUT2d data
28- const isce3::core::Matrix<T> & data = lut2d.data ();
29-
30- // Initialize working valarrays for computing mean along y-direction
31- std::valarray<double > values (lut2d.width ()), count (lut2d.width ());
32- values = 0.0 ;
33- count = 0.0 ;
34-
35- // Compute sum along columns (y-direction)
36- for (size_t i = 0 ; i < lut2d.length (); ++i) {
37- for (size_t j = 0 ; j < lut2d.width (); ++j) {
38- values[j] += data (i,j);
39- count[j] += 1.0 ;
40- }
41- }
42-
43- // Compute final coordinates and values
44- std::valarray<double > coords (lut2d.width ());
45- for (size_t j = 0 ; j < lut2d.width (); ++j) {
46- coords[j] = lut2d.xStart () + j * lut2d.xSpacing ();
47- values[j] /= count[j];
48- }
49-
50- // Save results
51- _coords = coords;
52- _values = values;
53- _extrapolate = true ;
54- _haveData = true ;
55- _refValue = lut2d.refValue ();
56- }
57-
58- // Assignment operator from an LUT2d (values averaged in y-direction)
59- /* * @param[in] lut2d LUT2d to copy data from */
60- template <typename T>
61- isce3::core::LUT1d<T> &
62- isce3::core::LUT1d<T>::
63- operator =(const LUT2d<T> & lut2d) {
64-
65- // Check if LUT2d has actual data; if not, just store reference value
66- if (!lut2d.haveData ()) {
67- _haveData = false ;
68- _refValue = lut2d.refValue ();
69- return *this ;
70- }
71-
72- // Get a reference to the LUT2d data
73- const isce3::core::Matrix<T> & data = lut2d.data ();
74-
75- // Initialize working valarrays for computing mean along y-direction
76- std::valarray<double > values (lut2d.width ()), count (lut2d.width ());
77- values = 0.0 ;
78- count = 0.0 ;
79-
80- // Compute sum along columns (y-direction)
81- for (size_t i = 0 ; i < lut2d.length (); ++i) {
82- for (size_t j = 0 ; j < lut2d.width (); ++j) {
83- values[j] += data (i,j);
84- count[j] += 1.0 ;
85- }
86- }
87-
88- // Compute final coordinates and values
89- std::valarray<double > coords (lut2d.width ());
90- for (size_t j = 0 ; j < lut2d.width (); ++j) {
91- coords[j] = lut2d.xStart () + j * lut2d.xSpacing ();
92- values[j] /= count[j];
93- }
94-
95- // Save results
96- _coords = coords;
97- _values = values;
98- _extrapolate = true ;
99- return *this ;
100- }
101-
1027/** @param[in] x Point to evaluate the LUT
1038 * @param[out] result Interpolated value */
1049template <typename T>
@@ -179,7 +84,7 @@ eval(double x) const {
17984 // The indices of the x bounds
18085 const int j0 = high - 1;
18186 const int j1 = high;
182-
87+
18388 // Get coordinates at bounds
18489 double x1 = _coords[j0];
18590 double x2 = _coords[j1];
@@ -189,4 +94,50 @@ eval(double x) const {
18994 return result;
19095}
19196
192- // end of file
97+ template <typename T>
98+ isce3::core::LUT1d<T>
99+ isce3::core::avgLUT2dToLUT1d(const isce3::core::LUT2d<T> & lut2d,
100+ const int axis) {
101+ if (axis != 0 && axis != 1) {
102+ std::string error_msg = "ERROR axis not equal to 0 or 1";
103+ throw isce3::except::InvalidArgument(ISCE_SRCINFO(), error_msg);
104+ }
105+
106+ // Check if LUT2d has actual data; if not, just return LUT1d with reference value
107+ if (!lut2d.haveData()) {
108+ return isce3::core::LUT1d<T>(lut2d.refValue());
109+ }
110+
111+ // Determine lut1d size and number of elements to sum
112+ const auto lut1d_size = (axis == 0) ? lut2d.width() : lut2d.length();
113+ const double n_to_sum_f = (axis == 0) ? static_cast<double>(lut2d.length()) :
114+ static_cast<double>(lut2d.width());
115+
116+ // Get a reference to the LUT2d data
117+ const Matrix<T> & data = lut2d.data();
118+
119+ // Compute sum and average
120+ isce3::core::EArray2D<double> ea_values;
121+ if (axis == 0)
122+ // Sum along rows (x-direction)
123+ ea_values = data.map().colwise().sum();
124+ else
125+ // Sum along columns (y-direction)
126+ ea_values = data.map().rowwise().sum();
127+ ea_values /= n_to_sum_f;
128+
129+ // Initialize working valarrays for computing mean along y-direction
130+ std::valarray<double> values(0.0, lut1d_size);
131+ std::copy(ea_values.data(), ea_values.data() + ea_values.size(), begin(values));
132+
133+ // Compute final coordinates and values
134+ std::valarray<double> coords(lut1d_size);
135+ for (size_t j = 0; j < lut1d_size; ++j) {
136+ if (axis == 0)
137+ coords[j] = lut2d.xStart() + j * lut2d.xSpacing();
138+ else
139+ coords[j] = lut2d.yStart() + j * lut2d.ySpacing();
140+ }
141+
142+ return isce3::core::LUT1d<T>(coords, values, true);
143+ }
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