Add TOSA MI verification methods

Adds utility functions that enable compliance verification of TOSA MI
operators; as per section 1.8.2 in the TOSA specification.

Signed-off-by: Georgios Pinitas <georgios.pinitas@arm.com>
Change-Id: I0cced0ff8875ac8d78b1943211438713d1c51b88

1 files changed, 130 insertions, 0 deletions

diff --git a/reference_model/src/verify.cc b/reference_model/src/verify.cc
new file mode 100644
index 0000000..940275f
--- /dev/null
+++ b/reference_model/src/verify.cc
@@ -0,0 +1,130 @@
+// Copyright (c) 2023, ARM Limited.
+//
+//    Licensed under the Apache License, Version 2.0 (the "License");
+//    you may not use this file except in compliance with the License.
+//    You may obtain a copy of the License at
+//
+//         http://www.apache.org/licenses/LICENSE-2.0
+//
+//    Unless required by applicable law or agreed to in writing, software
+//    distributed under the License is distributed on an "AS IS" BASIS,
+//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//    See the License for the specific language governing permissions and
+//    limitations under the License.
+//===----------------------------------------------------------------------===//
+//
+// Verification functionality as per TOSA Specification
+// Output Verification : Section 1.8.2
+//
+//===----------------------------------------------------------------------===//
+
+#include "verify.h"
+
+#include <half.hpp>
+
+#include <cmath>
+#include <numeric>
+#include <optional>
+#include <type_traits>
+
+#define REQUIRE(COND)                                                                                                  \
+    if (!(COND))                                                                                                       \
+    {                                                                                                                  \
+        return false;                                                                                                  \
+    }
+
+namespace
+{
+// Accumulator precision
+template <typename T>
+struct AccPrecision;
+template <>
+struct AccPrecision<float>
+{
+    static constexpr double precision = (double)(1 << 24);
+};
+template <>
+struct AccPrecision<half_float::half>
+{
+    static constexpr double precision = (double)(1 << 11);
+};
+
+// Generic element validation function
+template <typename AccType, typename std::enable_if_t<std::is_floating_point_v<AccType>, int> = 0>
+std::optional<double> validate_element(double ref, double bnd, AccType imp, size_t KS)
+{
+    double err    = 0.0;
+    bool is_valid = true;
+
+    if (bnd == 0.0)
+    {
+        is_valid = (ref == 0.0) && (imp == 0.0);
+        err      = 0.0;
+    }
+    else
+    {    // bnd > 0.0
+        const double imp_fp64      = static_cast<double>(imp);
+        const double acc_prec_fp64 = AccPrecision<AccType>::precision;
+        err                        = (imp_fp64 - ref) * acc_prec_fp64 / bnd;
+        is_valid                   = std::abs(err) <= KS;
+    }
+
+    return is_valid ? std::optional(err) : std::nullopt;
+}
+
+// Generic data validation function
+template <typename AccType, typename std::enable_if_t<std::is_floating_point_v<AccType>, int> = 0>
+bool validate_data(double* ref, double* bnd, AccType* imp, size_t T, size_t KS, int32_t S)
+{
+    double out_err_sum   = 0.0;
+    double out_err_sumsq = 0.0;
+
+    for (size_t i = 0; i < T; ++i)
+    {
+        auto out_err = validate_element<AccType>(ref[i], bnd[i], imp[i], KS);
+        REQUIRE(out_err);
+        out_err_sum += out_err.value();
+        out_err_sumsq += out_err.value() * out_err.value();
+    }
+
+    return tosa_validate_output_error(out_err_sum, out_err_sumsq, T, KS, S);
+}
+
+// Convert std::optional to CheckResult
+CheckResult from_optional(const std::optional<double>& res)
+{
+    if (res)
+        return { true, *res };
+    else
+        return { false, 0.0 };
+}
+}    // namespace
+
+extern "C" {
+
+CheckResult tosa_validate_element_accfp32(double ref, double bnd, float imp, size_t KS)
+{
+    auto err = validate_element<float>(ref, bnd, imp, KS);
+    return from_optional(err);
+}
+
+bool tosa_validate_output_error(double err_sum, double err_sum_sq, size_t T, size_t KS, int S)
+{
+    if (S != 1 && S != 2)
+    {
+        // Check error bias magnitude for data sets S which are not positive biased
+        REQUIRE(abs(err_sum) <= 2 * sqrt(KS * T));
+    }
+    // Check error variance magnitude
+    REQUIRE(err_sum_sq <= 0.4 * KS * T);
+
+    return true;
+}
+
+bool tosa_validate_data_fp32(double* ref, double* bnd, float* imp, size_t T, size_t KS, int S)
+{
+    return validate_data<float>(ref, bnd, imp, T, KS, S);
+}
+
+} // extern "C"
+#undef REQUIRE
\ No newline at end of file