OGS
PiecewiseLinearMonotonicCurve.cpp
Go to the documentation of this file.
1
13
#include "
PiecewiseLinearMonotonicCurve.h
"
14
15
#include <algorithm>
16
#include <cmath>
17
#include <limits>
18
19
#include "
BaseLib/Error.h
"
20
21
namespace
MathLib
22
{
23
PiecewiseLinearMonotonicCurve::PiecewiseLinearMonotonicCurve
(
24
std::vector<double> x, std::vector<double> y)
25
:
PiecewiseLinearInterpolation
(std::move(x), std::move(y), false)
26
{
27
if
(!
isStrongMonotonic
())
28
{
29
OGS_FATAL
(
"The given curve is not strong monotonic."
);
30
}
31
}
32
33
bool
PiecewiseLinearMonotonicCurve::isStrongMonotonic
()
const
34
{
35
const
double
gradient0 =
getDerivative
(
supp_pnts_
[0]);
36
37
if
(std::abs(gradient0) < std::numeric_limits<double>::min())
38
{
39
return
false
;
40
}
41
42
return
std::none_of(
supp_pnts_
.begin(),
supp_pnts_
.end(),
43
[&](
const
double
p
)
44
{ return this->getDerivative(p) * gradient0 <= 0.; });
45
}
46
47
double
PiecewiseLinearMonotonicCurve::getInverseVariable
(
const
double
y)
const
48
{
49
std::size_t interval_idx = 0;
50
if
(
values_at_supp_pnts_
.front() <
values_at_supp_pnts_
.back())
51
{
52
if
(y <=
values_at_supp_pnts_
.front())
53
{
54
return
supp_pnts_
[0];
55
}
56
if
(y >=
values_at_supp_pnts_
.back())
57
{
58
return
supp_pnts_
[
supp_pnts_
.size() - 1];
59
}
60
61
// search interval that has the point inside
62
auto
const
& it(std::lower_bound(
values_at_supp_pnts_
.begin(),
63
values_at_supp_pnts_
.end(), y));
64
interval_idx = std::distance(
values_at_supp_pnts_
.begin(), it) - 1;
65
}
66
else
67
{
68
if
(y >=
values_at_supp_pnts_
.front())
69
{
70
return
supp_pnts_
[0];
71
}
72
if
(y <=
values_at_supp_pnts_
.back())
73
{
74
return
supp_pnts_
[
supp_pnts_
.size() - 1];
75
}
76
77
// search interval in the reverse direction for the point inside
78
auto
const
& it(std::lower_bound(
values_at_supp_pnts_
.rbegin(),
79
values_at_supp_pnts_
.rend(), y));
80
interval_idx =
values_at_supp_pnts_
.size() -
81
(std::distance(
values_at_supp_pnts_
.rbegin(), it)) - 1;
82
}
83
84
const
double
xi_1 =
supp_pnts_
[interval_idx + 1];
85
const
double
xi =
supp_pnts_
[interval_idx];
86
const
double
yi_1 =
values_at_supp_pnts_
[interval_idx + 1];
87
const
double
yi =
values_at_supp_pnts_
[interval_idx];
88
89
// compute gradient: m = (x_{i+1} - x_i) / (y_{i+1} - y_i)
90
const
double
m = (xi_1 - xi) / (yi_1 - yi);
91
92
// compute the variable by linear interpolation: x = m * (y - y_i) + x_i,
93
// and then return the result.
94
return
m * (y - yi) + xi;
95
}
96
97
}
// namespace MathLib
Error.h
OGS_FATAL
#define OGS_FATAL(...)
Definition
Error.h:26
PiecewiseLinearMonotonicCurve.h
MathLib::PiecewiseLinearInterpolation
Definition
PiecewiseLinearInterpolation.h:26
MathLib::PiecewiseLinearInterpolation::supp_pnts_
std::vector< double > supp_pnts_
Definition
PiecewiseLinearInterpolation.h:79
MathLib::PiecewiseLinearInterpolation::values_at_supp_pnts_
std::vector< double > values_at_supp_pnts_
Definition
PiecewiseLinearInterpolation.h:80
MathLib::PiecewiseLinearInterpolation::getDerivative
double getDerivative(double const pnt_to_interpolate) const
Calculates derivative using quadratic interpolation and central difference quotient.
Definition
PiecewiseLinearInterpolation.cpp:82
MathLib::PiecewiseLinearMonotonicCurve::isStrongMonotonic
bool isStrongMonotonic() const
Definition
PiecewiseLinearMonotonicCurve.cpp:33
MathLib::PiecewiseLinearMonotonicCurve::PiecewiseLinearMonotonicCurve
PiecewiseLinearMonotonicCurve(std::vector< double > x, std::vector< double > y)
Definition
PiecewiseLinearMonotonicCurve.cpp:23
MathLib::PiecewiseLinearMonotonicCurve::getInverseVariable
double getInverseVariable(const double y) const
Definition
PiecewiseLinearMonotonicCurve.cpp:47
MathLib
Definition
CreateComponent.h:32
MathLib::p
static const double p
Definition
GaussLegendreTet.cpp:62
MathLib
Curve
PiecewiseLinearMonotonicCurve.cpp
Generated by
1.10.0