1 /* --------------------------------------------------------------------------
2 CppAD: C++ Algorithmic Differentiation: Copyright (C) 2003-20 Bradley M. Bell
3
4 CppAD is distributed under the terms of the
5 Eclipse Public License Version 2.0.
6
7 This Source Code may also be made available under the following
8 Secondary License when the conditions for such availability set forth
9 in the Eclipse Public License, Version 2.0 are satisfied:
10 GNU General Public License, Version 2.0 or later.
11 ---------------------------------------------------------------------------- */
12
13 /*
14 $begin capacity_order.cpp$$
15 $spell
16 Taylor
17 $$
18
19 $section Controlling Taylor Coefficient Memory Allocation: Example and Test$$
20
21
22 $srcthisfile%0%// BEGIN C++%// END C++%1%$$
23
24 $end
25 */
26 // BEGIN C++
27 # include <cppad/cppad.hpp>
28
29 namespace {
test(void)30 bool test(void)
31 { bool ok = true;
32 using CppAD::AD;
33 using CppAD::NearEqual;
34 using CppAD::thread_alloc;
35
36 // domain space vector
37 size_t n(1), m(1);
38 CPPAD_TESTVECTOR(AD<double>) ax(n), ay(n);
39
40 // declare independent variables and start tape recording
41 ax[0] = 1.0;
42 CppAD::Independent(ax);
43
44 // Set y = x^3, use enough variables so more that the minimal amount
45 // of memory is allocated for Taylor coefficients
46 ay[0] = 0.;
47 for( size_t i = 0; i < 10; i++)
48 ay[0] += ax[0] * ax[0] * ax[0];
49 ay[0] = ay[0] / 10.;
50
51 // create f: x -> y and stop tape recording
52 // (without running zero order forward mode).
53 CppAD::ADFun<double> f;
54 f.Dependent(ax, ay);
55
56 // check that this is master thread
57 size_t thread = thread_alloc::thread_num();
58 ok &= thread == 0; // this should be master thread
59
60 // The highest order forward mode calculation below is first order.
61 // This corresponds to two Taylor coefficient per variable,direction
62 // (orders zero and one). Preallocate memory for speed.
63 size_t inuse = thread_alloc::inuse(thread);
64 f.capacity_order(2);
65 ok &= thread_alloc::inuse(thread) > inuse;
66
67 // zero order forward mode
68 CPPAD_TESTVECTOR(double) x(n), y(m);
69 x[0] = 0.5;
70 y = f.Forward(0, x);
71 double eps = 10. * CppAD::numeric_limits<double>::epsilon();
72 ok &= NearEqual(y[0], x[0] * x[0] * x[0], eps, eps);
73
74 // forward computation of partials w.r.t. x
75 CPPAD_TESTVECTOR(double) dx(n), dy(m);
76 dx[0] = 1.;
77 dy = f.Forward(1, dx);
78 ok &= NearEqual(dy[0], 3. * x[0] * x[0], eps, eps);
79
80 // Suppose we no longer need the first order Taylor coefficients.
81 inuse = thread_alloc::inuse(thread);
82 f.capacity_order(1); // just keep zero order coefficients
83 ok &= thread_alloc::inuse(thread) < inuse;
84
85 // Suppose we no longer need the zero order Taylor coefficients
86 // (could have done this first and not used f.capacity_order(1)).
87 inuse = thread_alloc::inuse(thread);
88 f.capacity_order(0);
89 ok &= thread_alloc::inuse(thread) < inuse;
90
91 // turn off memory holding
92 thread_alloc::hold_memory(false);
93
94 return ok;
95 }
96 }
capacity_order(void)97 bool capacity_order(void)
98 { bool ok = true;
99 using CppAD::thread_alloc;
100
101 // original amount of memory inuse
102 size_t thread = thread_alloc::thread_num();
103 ok &= thread == 0; // this should be master thread
104 size_t inuse = thread_alloc::inuse(thread);
105
106 // do test in separate routine so all objects are destroyed
107 ok &= test();
108
109 // check that the amount of memroy inuse has not changed
110 ok &= thread_alloc::inuse(thread) == inuse;
111
112 // Test above uses hold_memory, so return available memory
113 thread_alloc::free_available(thread);
114
115 return ok;
116 }
117
118 // END C++
119