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sparse_example.cpp
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1// $Id$
2// $Source$
3// @HEADER
4// ***********************************************************************
5//
6// Sacado Package
7// Copyright (2006) Sandia Corporation
8//
9// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
10// the U.S. Government retains certain rights in this software.
11//
12// This library is free software; you can redistribute it and/or modify
13// it under the terms of the GNU Lesser General Public License as
14// published by the Free Software Foundation; either version 2.1 of the
15// License, or (at your option) any later version.
16//
17// This library is distributed in the hope that it will be useful, but
18// WITHOUT ANY WARRANTY; without even the implied warranty of
19// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20// Lesser General Public License for more details.
21//
22// You should have received a copy of the GNU Lesser General Public
23// License along with this library; if not, write to the Free Software
24// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
25// USA
26// Questions? Contact David M. Gay (dmgay@sandia.gov) or Eric T. Phipps
27// (etphipp@sandia.gov).
28//
29// ***********************************************************************
30// @HEADER
31
32// dfad_example
33//
34// usage:
35// dfad_example
36//
37// output:
38// prints the results of differentiating a simple function with forward
39// mode AD using the Sacado::Fad::DFad class (uses dynamic memory
40// allocation for number of derivative components).
41
42#include <iostream>
43#include <iomanip>
44
45#include "Sacado_No_Kokkos.hpp"
46
47// The function to differentiate
48template <typename ScalarT>
49ScalarT func(const ScalarT& a, const ScalarT& b, const ScalarT& c) {
50 ScalarT r = std::log(b+1.)/std::sin(a);
51
52 return r;
53}
54
56
57int main(int argc, char **argv)
58{
59 double pi = std::atan(1.0)*4.0;
60
61 // Values of function arguments
62 double a = pi/4;
63 double b = 2.0;
64 double c = 3.0;
65
66 // Number of independent variables
67 int num_deriv = 3;
68
69 // Fad objects
70 FadType afad(num_deriv, 0, a); // First (0) indep. var
71 FadType bfad(num_deriv, 1, b); // Second (1) indep. var
72 FadType cfad(num_deriv, 2, c); // Third (2) indep. var
73 FadType rfad; // Result
74
75 // Compute function
76 double r = func(a, b, c);
77
78 // Compute function and derivative with AD
79 rfad = func(afad, bfad, cfad);
80
81 std::cout << rfad << std::endl;
82
83 // Extract value and derivatives
84 double r_ad = rfad.val(); // r
85 bool drda_ad = rfad.dx(0); // dr/da
86 bool drdb_ad = rfad.dx(1); // dr/db
87 bool drdc_ad = rfad.dx(2); // dr/dc
88
89 double tol = 1.0e-14;
90 if (std::fabs(r - r_ad) < tol && drda_ad && drdb_ad && !drdc_ad) {
91 std::cout << "\nExample passed!" << std::endl;
92 return 0;
93 }
94 else {
95 std::cout <<"\nSomething is wrong, example failed!" << std::endl;
96 return 1;
97 }
98}
expr expr1 expr1 expr1 c expr2 expr1 expr2 expr1 expr2 expr1 expr1 expr1 expr1 c expr2 expr1 expr2 expr1 expr2 expr1 expr1 expr1 expr1 c *expr2 expr1 expr2 expr1 expr2 expr1 expr1 expr1 expr1 c expr2 expr1 expr2 expr1 expr2 expr1 expr1 expr1 expr2 expr1 expr2 expr1 expr1 expr1 expr2 expr1 expr2 expr1 expr1 expr1 c
int main()
User inteface class for computing the logical sparsity pattern of a derivative via forward-mode AD.
Sacado::LFad::LogicalSparse< double, bool > FadType
ScalarT func(const ScalarT &a, const ScalarT &b, const ScalarT &c)
const double tol