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4527dcad1e8da125197cc865d566f34e21a650ce
external_libcamera/test/ipa/libipa/fixedpoint.cpp
Kieran Bingham 4527dcad1e test: libipa: Provide FixedPoint Quantized tests 
Provide tests to validate the conditions of FixedPoint types used
within libcamera explicitly.

Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Isaac Scott <isaac.scott@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2026-02-19 15:06:21 +00:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2024, Paul Elder <paul.elder@ideasonboard.com>
*
* Fixed / Floating point utility tests
*/
#include "../src/ipa/libipa/fixedpoint.h"
#include <cmath>
#include <iostream>
#include <map>
#include <stdint.h>
#include <libcamera/base/utils.h>
#include "test.h"
using namespace std;
using namespace libcamera;
using namespace ipa;
class FixedPointUtilsTest : public Test
{
protected:
/* R for real, I for integer */
template<unsigned int IntPrec, unsigned int FracPrec, typename I, typename R>
int testFixedToFloat(I input, R expected)
{
R out = fixedToFloatingPoint<IntPrec, FracPrec, R>(input);
R prec = 1.0 / (1 << FracPrec);
if (std::abs(out - expected) > prec) {
cerr << "Reverse conversion expected " << input
<< " to convert to " << expected
<< ", got " << out << std::endl;
return TestFail;
}
return TestPass;
}
template<unsigned int IntPrec, unsigned int FracPrec, typename T>
int testSingleFixedPoint(double input, T expected)
{
T ret = floatingToFixedPoint<IntPrec, FracPrec, T>(input);
if (ret != expected) {
cerr << "Expected " << input << " to convert to "
<< expected << ", got " << ret << std::endl;
return TestFail;
}
/*
* The precision check is fairly arbitrary but is based on what
* the rkisp1 is capable of in the crosstalk module.
*/
double f = fixedToFloatingPoint<IntPrec, FracPrec, double>(ret);
if (std::abs(f - input) > 0.005) {
cerr << "Reverse conversion expected " << ret
<< " to convert to " << input
<< ", got " << f << std::endl;
return TestFail;
}
return TestPass;
}
int testFixedPoint()
{
/*
* The second 7.992 test is to test that unused bits don't
* affect the result.
*/
std::map<double, int16_t> testCases = {
{ 7.992, 0x3ff },
{ 0.2, 0x01a },
{ -0.2, 0x7e6 },
{ -0.8, 0x79a },
{ -0.4, 0x7cd },
{ -1.4, 0x74d },
{ -8, 0x400 },
{ 0, 0 },
};
int ret;
for (const auto &testCase : testCases) {
ret = testSingleFixedPoint<4, 7, int16_t>(testCase.first,
testCase.second);
if (ret != TestPass)
return ret;
}
/* Special case with a superfluous one in the unused bits */
ret = testFixedToFloat<4, 7, int16_t, double>(0xbff, 7.992);
if (ret != TestPass)
return ret;
return TestPass;
}
template<typename Q>
int quantizedCheck(float input, typename Q::QuantizedType expected, float value)
{
Q q(input);
using T = typename Q::QuantizedType;
std::cout << " Checking " << input << " == " << q << std::endl;
T quantized = q.quantized();
if (quantized != expected) {
std::cout << " ** Q Expected " << input
<< " to quantize to " << utils::hex(expected)
<< ", got " << utils::hex(quantized)
<< " - (" << q << ")"
<< std::endl;
return 1;
}
if ((std::abs(q.value() - value)) > 0.0001f) {
std::cout << " ** V Expected " << input
<< " to quantize to " << value
<< ", got " << q.value()
<< " - (" << q << ")"
<< std::endl;
return 1;
}
return 0;
}
template<typename Q, typename RegisterType>
int signExtendCheck()
{
Q minValue(Q::TraitsType::min);
using T = typename Q::QuantizedType;
T minQuantized = minValue.quantized();
/* Take the value and expand it into a larger register */
RegisterType reg = static_cast<RegisterType>(minValue.quantized());
std::cout << " Checking " << minValue << " == " << utils::hex(reg) << std::endl;
/*
* Ensure that the minimum negative value is not sign
* extended when casting up to a larger register storage
* type.
*/
if (reg != minQuantized) {
std::cout << " ** Sign extension check failed for min value. Expected "
<< utils::hex(minQuantized) << ", got "
<< utils::hex(reg) << std::endl;
return 1;
}
/* And we should be consistent when we convert back to Q */
Q q2(static_cast<T>(reg));
if (!(q2 == minValue)) {
std::cout << " ** Sign extension check failed for min value. Expected "
<< minValue << ", got " << q2 << std::endl;
return 1;
}
return 0;
}
template<typename Q>
void introduce(std::string_view type)
{
using T = typename Q::QuantizedType;
std::cout << std::endl;
std::cout << type
<< "(" << Q::TraitsType::min << " .. " << Q::TraitsType::max << ") "
<< " Min: " << Q(Q::TraitsType::min)
<< " -- Max: " << Q(Q::TraitsType::max)
<< " Step:" << Q(T(1)).value()
<< std::endl;
}
int testFixedPointQuantizers()
{
unsigned int fails = 0;
/*
* These aim to specifically test all the corner cases of the
* quantization and de-quantization process. Including clamping
* to min/max, zero points and making sure that steps are
* correct.
*
* In particular test signed and unsigned types and a mix of the
* highest bit width of a storage type and smaller widths that
* require bit masking and sign extension.
*
* Note we must hard code these. Any calculation of expected
* values risks replicating bugs in the implementation.
*
* As the underlying types are integer and float the limit of
* precision is around 24 bits so we do not test wider types.
*/
/* clang-format off */
/* Q1.7(-1 .. 0.992188) Min: [0x80:-1] -- Max: [0x7f:0.992188] Step:0.0078125*/
introduce<Q<1, 7>>("Q1.7");
fails += quantizedCheck<Q<1, 7>>(-2.000f, 0b1'0000000, -1.0f); /* Clamped to Min */
fails += quantizedCheck<Q<1, 7>>(-1.000f, 0b1'0000000, -1.0f); /* Min */
fails += quantizedCheck<Q<1, 7>>(-0.992f, 0b1'0000001, -0.992188f); /* Min + 1 step */
fails += quantizedCheck<Q<1, 7>>(-0.006f, 0b1'1111111, -0.0078125f); /* -1 step */
fails += quantizedCheck<Q<1, 7>>( 0.000f, 0b0'0000000, 0.0f); /* Zero */
fails += quantizedCheck<Q<1, 7>>( 0.008f, 0b0'0000001, 0.0078125f); /* +1 step */
fails += quantizedCheck<Q<1, 7>>( 0.992f, 0b0'1111111, 0.992188f); /* Max */
fails += quantizedCheck<Q<1, 7>>( 2.000f, 0b0'1111111, 0.992188f); /* Clamped to Max */
/* UQ1.7(0 .. 1.99219) Min: [0x00:0] -- Max: [0xff:1.99219] Step:0.0078125 */
introduce<UQ<1, 7>>("UQ1.7");
fails += quantizedCheck<UQ<1, 7>>(-1.0f, 0b0'0000000, 0.0f); /* Clamped to Min */
fails += quantizedCheck<UQ<1, 7>>( 0.0f, 0b0'0000000, 0.0f); /* Min / Zero */
fails += quantizedCheck<UQ<1, 7>>( 1.0f, 0b1'0000000, 1.0f); /* Mid */
fails += quantizedCheck<UQ<1, 7>>( 1.992f, 0b1'1111111, 1.99219f); /* Max */
fails += quantizedCheck<UQ<1, 7>>( 2.000f, 0b1'1111111, 1.99219f); /* Clamped to Max */
/* UQ4.8(0 .. 15.9961) Min: [0x0000:0] -- Max: [0x0fff:15.9961] Step:0.00390625 */
introduce<UQ<4, 8>>("UQ4.8");
fails += quantizedCheck<UQ<4, 8>>( 0.0f, 0b0000'00000000, 0.00f);
fails += quantizedCheck<UQ<4, 8>>(16.0f, 0b1111'11111111, 15.9961f);
/* Q5.4(-16 .. 15.9375) Min: [0x0100:-16] -- Max: [0x00ff:15.9375] Step:0.0625 */
introduce<Q<5, 4>>("Q5.4");
fails += quantizedCheck<Q<5, 4>>(-16.00f, 0b10000'0000, -16.00f);
fails += quantizedCheck<Q<5, 4>>( 15.94f, 0b01111'1111, 15.9375f);
/* UQ5.8(0 .. 31.9961) Min: [0x0000:0] -- Max: [0x1fff:31.9961] Step:0.00390625 */
introduce<UQ<5, 8>>("UQ5.8");
fails += quantizedCheck<UQ<5, 8>>( 0.00f, 0b00000'00000000, 0.00f);
fails += quantizedCheck<UQ<5, 8>>(32.00f, 0b11111'11111111, 31.9961f);
/* Q12.4(-2048 .. 2047.94) Min: [0x8000:-2048] -- Max: [0x7fff:2047.94] Step:0.0625 */
introduce<Q<12, 4>>("Q12.4");
fails += quantizedCheck<Q<12, 4>>( 0.0f, 0b000000000000'0000, 0.0f);
fails += quantizedCheck<Q<12, 4>>( 7.5f, 0b000000000111'1000, 7.5f);
/* UQ12.4(0 .. 4095.94) Min: [0x0000:0] -- Max: [0xffff:4095.94] Step:0.0625 */
introduce<UQ<12, 4>>("UQ12.4");
fails += quantizedCheck<UQ<12, 4>>(0.0f, 0b000000000000'0000, 0.0f);
fails += quantizedCheck<UQ<12, 4>>(7.5f, 0b000000000111'1000, 7.5f);
/* Q4.20 */
introduce<Q<4, 20>>("Q4.20");
fails += quantizedCheck<Q<4, 20>>( -9.0f, 0b1000'00000000000000000000, -8.0f);
fails += quantizedCheck<Q<4, 20>>( -8.0f, 0b1000'00000000000000000000, -8.0f);
fails += quantizedCheck<Q<4, 20>>( 8.0f, 0b0111'11111111111111111111, 8.0f);
fails += quantizedCheck<Q<4, 20>>( 9.0f, 0b0111'11111111111111111111, 8.0f);
/* UQ4.20 */
introduce<UQ<4, 20>>("UQ4.20");
fails += quantizedCheck<UQ<4, 20>>(-1.0f, 0b0000'00000000000000000000, 0.0f);
fails += quantizedCheck<UQ<4, 20>>( 0.0f, 0b0000'00000000000000000000, 0.0f);
fails += quantizedCheck<UQ<4, 20>>(16.0f, 0b1111'11111111111111111111, 16.0f);
fails += quantizedCheck<UQ<4, 20>>(20.0f, 0b1111'11111111111111111111, 16.0f);
/* Storage selection tests */
static_assert(std::is_same_v<typename Q<4, 4>::TraitsType::QuantizedType, uint8_t>);
static_assert(std::is_same_v<typename UQ<4, 4>::TraitsType::QuantizedType, uint8_t>);
static_assert(std::is_same_v<typename Q<8, 8>::TraitsType::QuantizedType, uint16_t>);
static_assert(std::is_same_v<typename UQ<8, 8>::TraitsType::QuantizedType, uint16_t>);
static_assert(std::is_same_v<typename Q<20, 4>::TraitsType::QuantizedType, uint32_t>);
static_assert(std::is_same_v<typename UQ<20, 4>::TraitsType::QuantizedType, uint32_t>);
/*
* Test and validate that sign extension can not modify a
* quantized value when stored or cast to a larger register.
*/
std::cout << std::endl;
std::cout << "Testing sign extension of quantized values when cast to larger registers" << std::endl;
fails += signExtendCheck<Q<2, 4>, uint8_t>();
fails += signExtendCheck<Q<4, 4>, uint8_t>();
fails += signExtendCheck<Q<4, 4>, uint16_t>();
fails += signExtendCheck<Q<8, 8>, uint16_t>();
fails += signExtendCheck<Q<8, 8>, uint32_t>();
/* clang-format on */
std::cout << std::endl;
if (fails > 0) {
cout << "Fixed point quantizer tests failed: "
<< std::dec << fails << " failures." << std::endl;
return TestFail;
}
return TestPass;
}
int run()
{
unsigned int fails = 0;
/* fixed point conversion test */
if (testFixedPoint() != TestPass)
fails++;
if (testFixedPointQuantizers() != TestPass)
fails++;
return fails ? TestFail : TestPass;
}
};
TEST_REGISTER(FixedPointUtilsTest)
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