NumericDiffFunctor.

A wrapper class that takes a variadic functor evaluating a
function, numerically differentiates it and makes it available as a
templated functor so that it can be easily used as part of Ceres'
automatic differentiation framework.

The tests for NumericDiffCostFunction and NumericDiffFunctor have
a lot of stuff that is common, so refactor them to reduce code.

Change-Id: I83b01e58b05e575fb2530d15cbd611928298646a
This commit is contained in:
Sameer Agarwal
2013-01-18 13:11:32 -08:00
parent 2fc0ed6143
commit 2f0d7249cc
6 changed files with 726 additions and 190 deletions
+74 -189
View File
@@ -36,8 +36,7 @@
#include <vector>
#include "ceres/internal/macros.h"
#include "ceres/internal/scoped_ptr.h"
#include "ceres/sized_cost_function.h"
#include "ceres/stringprintf.h"
#include "ceres/numeric_diff_test_utils.h"
#include "ceres/test_util.h"
#include "ceres/types.h"
#include "glog/logging.h"
@@ -46,223 +45,109 @@
namespace ceres {
namespace internal {
// y1 = x1'x2 -> dy1/dx1 = x2, dy1/dx2 = x1
// y2 = (x1'x2)^2 -> dy2/dx1 = 2 * x2 * (x1'x2), dy2/dx2 = 2 * x1 * (x1'x2)
// y3 = x2'x2 -> dy3/dx1 = 0, dy3/dx2 = 2 * x2
struct EasyFunctor {
bool operator()(const double* x1, const double* x2, double* residuals) const {
residuals[0] = residuals[1] = residuals[2] = 0;
for (int i = 0; i < 5; ++i) {
residuals[0] += x1[i] * x2[i];
residuals[2] += x2[i] * x2[i];
}
residuals[1] = residuals[0] * residuals[0];
return true;
}
};
TEST(NumericDiffCostFunction, EasyCaseFunctorCentralDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<EasyFunctor,
CENTRAL,
3, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new EasyFunctor));
EasyFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, CENTRAL);
}
class EasyCostFunction : public SizedCostFunction<3, 5, 5> {
public:
virtual bool Evaluate(double const* const* parameters,
double* residuals,
double** jacobians) const {
(void) jacobians; // Ignored.
return EasyFunctor()(parameters[0], parameters[1], residuals);
}
};
TEST(NumericDiffCostFunction, EasyCaseFunctorForwardDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<EasyFunctor,
FORWARD,
3, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new EasyFunctor));
EasyFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, FORWARD);
}
TEST(NumericDiffCostFunction, EasyCase) {
// Try both central and forward difference.
internal::scoped_ptr<CostFunction> cfs[4];
cfs[0].reset(
TEST(NumericDiffCostFunction, EasyCaseCostFunctionCentralDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<EasyCostFunction,
CENTRAL,
3, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new EasyCostFunction, TAKE_OWNERSHIP));
EasyFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, CENTRAL);
}
cfs[1].reset(
TEST(NumericDiffCostFunction, EasyCaseCostFunctionForwardDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<EasyCostFunction,
FORWARD,
3, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new EasyCostFunction, TAKE_OWNERSHIP));
cfs[2].reset(
new NumericDiffCostFunction< EasyFunctor,
CENTRAL,
3, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new EasyFunctor));
cfs[3].reset(
new NumericDiffCostFunction< EasyFunctor,
FORWARD,
3, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new EasyFunctor));
for (int c = 0; c < 4; ++c) {
CostFunction *cost_function = cfs[c].get();
double x1[] = { 1.0, 2.0, 3.0, 4.0, 5.0 };
double x2[] = { 9.0, 9.0, 5.0, 5.0, 1.0 };
double *parameters[] = { &x1[0], &x2[0] };
double dydx1[15]; // 3 x 5, row major.
double dydx2[15]; // 3 x 5, row major.
double *jacobians[2] = { &dydx1[0], &dydx2[0] };
double residuals[3] = {-1e-100, -2e-100, -3e-100 };
ASSERT_TRUE(cost_function->Evaluate(&parameters[0],
&residuals[0],
&jacobians[0]));
EXPECT_EQ(residuals[0], 67);
EXPECT_EQ(residuals[1], 4489);
EXPECT_EQ(residuals[2], 213);
for (int i = 0; i < 5; ++i) {
LOG(INFO) << "c = " << c << " i = " << i;
const double kEps = c == 0 ? /* central */ 3e-9 : /* forward */ 2e-5;
ExpectClose(x2[i], dydx1[5 * 0 + i], kEps); // y1
ExpectClose(x1[i], dydx2[5 * 0 + i], kEps);
ExpectClose(2 * x2[i] * residuals[0], dydx1[5 * 1 + i], kEps); // y2
ExpectClose(2 * x1[i] * residuals[0], dydx2[5 * 1 + i], kEps);
ExpectClose(0.0, dydx1[5 * 2 + i], kEps); // y3
ExpectClose(2 * x2[i], dydx2[5 * 2 + i], kEps);
}
}
EasyFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, FORWARD);
}
// y1 = sin(x1'x2)
// y2 = exp(-x1'x2 / 10)
//
// dy1/dx1 = x2 * cos(x1'x2), dy1/dx2 = x1 * cos(x1'x2)
// dy2/dx1 = -x2 * exp(-x1'x2 / 10) / 10, dy2/dx2 = -x2 * exp(-x1'x2 / 10) / 10
struct TranscendentalFunctor {
bool operator()(const double* x1, const double* x2, double* residuals) const {
double x1x2 = 0;
for (int i = 0; i < 5; ++i) {
x1x2 += x1[i] * x2[i];
}
residuals[0] = sin(x1x2);
residuals[1] = exp(-x1x2 / 10);
return true;
}
};
class TranscendentalTestCostFunction : public SizedCostFunction<2, 5, 5> {
public:
virtual bool Evaluate(double const* const* parameters,
double* residuals,
double** jacobians) const {
(void) jacobians; // Ignored.
return TranscendentalFunctor()(parameters[0], parameters[1], residuals);
}
};
TEST(NumericDiffCostFunction, TransendentalOperationsInCostFunction) {
// Try both central and forward difference.
internal::scoped_ptr<CostFunction> cfs[4];
cfs[0].reset(
new NumericDiffCostFunction<TranscendentalTestCostFunction,
CENTRAL,
2, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new TranscendentalTestCostFunction, TAKE_OWNERSHIP));
cfs[1].reset(
new NumericDiffCostFunction<TranscendentalTestCostFunction,
FORWARD,
2, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new TranscendentalTestCostFunction, TAKE_OWNERSHIP));
cfs[2].reset(
TEST(NumericDiffCostFunction, TranscendentalCaseFunctorCentralDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<TranscendentalFunctor,
CENTRAL,
2, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new TranscendentalFunctor));
new TranscendentalFunctor));
TranscendentalFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, CENTRAL);
}
cfs[3].reset(
TEST(NumericDiffCostFunction, TranscendentalCaseFunctorForwardDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<TranscendentalFunctor,
FORWARD,
2, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new TranscendentalFunctor));
for (int c = 0; c < 4; ++c) {
CostFunction *cost_function = cfs[c].get();
struct {
double x1[5];
double x2[5];
} kTests[] = {
{ { 1.0, 2.0, 3.0, 4.0, 5.0 }, // No zeros.
{ 9.0, 9.0, 5.0, 5.0, 1.0 },
},
{ { 0.0, 2.0, 3.0, 0.0, 5.0 }, // Some zeros x1.
{ 9.0, 9.0, 5.0, 5.0, 1.0 },
},
{ { 1.0, 2.0, 3.0, 1.0, 5.0 }, // Some zeros x2.
{ 0.0, 9.0, 0.0, 5.0, 0.0 },
},
{ { 0.0, 0.0, 0.0, 0.0, 0.0 }, // All zeros x1.
{ 9.0, 9.0, 5.0, 5.0, 1.0 },
},
{ { 1.0, 2.0, 3.0, 4.0, 5.0 }, // All zeros x2.
{ 0.0, 0.0, 0.0, 0.0, 0.0 },
},
{ { 0.0, 0.0, 0.0, 0.0, 0.0 }, // All zeros.
{ 0.0, 0.0, 0.0, 0.0, 0.0 },
},
};
for (int k = 0; k < CERES_ARRAYSIZE(kTests); ++k) {
double *x1 = &(kTests[k].x1[0]);
double *x2 = &(kTests[k].x2[0]);
double *parameters[] = { x1, x2 };
double dydx1[10];
double dydx2[10];
double *jacobians[2] = { &dydx1[0], &dydx2[0] };
double residuals[2];
ASSERT_TRUE(cost_function->Evaluate(&parameters[0],
&residuals[0],
&jacobians[0]));
LOG(INFO) << "Ran evaluate for test k=" << k << " c=" << c;
double x1x2 = 0;
for (int i = 0; i < 5; ++i) {
x1x2 += x1[i] * x2[i];
}
for (int i = 0; i < 5; ++i) {
const double kEps = c == 0 ? /* central */ 3e-9 : /* forward */ 2e-5;
ExpectClose( x2[i] * cos(x1x2), dydx1[5 * 0 + i], kEps);
ExpectClose( x1[i] * cos(x1x2), dydx2[5 * 0 + i], kEps);
ExpectClose(-x2[i] * exp(-x1x2 / 10.) / 10., dydx1[5 * 1 + i], kEps);
ExpectClose(-x1[i] * exp(-x1x2 / 10.) / 10., dydx2[5 * 1 + i], kEps);
}
}
}
new TranscendentalFunctor));
TranscendentalFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, FORWARD);
}
TEST(NumericDiffCostFunction, TranscendentalCaseCostFunctionCentralDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<TranscendentalCostFunction,
CENTRAL,
2, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new TranscendentalCostFunction, TAKE_OWNERSHIP));
TranscendentalFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, CENTRAL);
}
TEST(NumericDiffCostFunction, TranscendentalCaseCostFunctionForwardDifferences) {
internal::scoped_ptr<CostFunction> cost_function;
cost_function.reset(
new NumericDiffCostFunction<TranscendentalCostFunction,
FORWARD,
2, /* number of residuals */
5, /* size of x1 */
5 /* size of x2 */>(
new TranscendentalCostFunction, TAKE_OWNERSHIP));
TranscendentalFunctor functor;
functor.ExpectCostFunctionEvaluationIsNearlyCorrect(*cost_function, FORWARD);
}
template<int num_rows, int num_cols>
class SizeTestingCostFunction : public SizedCostFunction<num_rows, num_cols> {