llvm-project/flang/lib/Evaluate/complex.cpp

107 lines
3.9 KiB
C++

//===-- lib/Evaluate/complex.cpp ------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "flang/Evaluate/complex.h"
#include "llvm/Support/raw_ostream.h"
namespace Fortran::evaluate::value {
template <typename R>
ValueWithRealFlags<Complex<R>> Complex<R>::Add(
const Complex &that, Rounding rounding) const {
RealFlags flags;
Part reSum{re_.Add(that.re_, rounding).AccumulateFlags(flags)};
Part imSum{im_.Add(that.im_, rounding).AccumulateFlags(flags)};
return {Complex{reSum, imSum}, flags};
}
template <typename R>
ValueWithRealFlags<Complex<R>> Complex<R>::Subtract(
const Complex &that, Rounding rounding) const {
RealFlags flags;
Part reDiff{re_.Subtract(that.re_, rounding).AccumulateFlags(flags)};
Part imDiff{im_.Subtract(that.im_, rounding).AccumulateFlags(flags)};
return {Complex{reDiff, imDiff}, flags};
}
template <typename R>
ValueWithRealFlags<Complex<R>> Complex<R>::Multiply(
const Complex &that, Rounding rounding) const {
// (a + ib)*(c + id) -> ac - bd + i(ad + bc)
RealFlags flags;
Part ac{re_.Multiply(that.re_, rounding).AccumulateFlags(flags)};
Part bd{im_.Multiply(that.im_, rounding).AccumulateFlags(flags)};
Part ad{re_.Multiply(that.im_, rounding).AccumulateFlags(flags)};
Part bc{im_.Multiply(that.re_, rounding).AccumulateFlags(flags)};
Part acbd{ac.Subtract(bd, rounding).AccumulateFlags(flags)};
Part adbc{ad.Add(bc, rounding).AccumulateFlags(flags)};
return {Complex{acbd, adbc}, flags};
}
template <typename R>
ValueWithRealFlags<Complex<R>> Complex<R>::Divide(
const Complex &that, Rounding rounding) const {
// (a + ib)/(c + id) -> [(a+ib)*(c-id)] / [(c+id)*(c-id)]
// -> [ac+bd+i(bc-ad)] / (cc+dd)
// -> ((ac+bd)/(cc+dd)) + i((bc-ad)/(cc+dd))
// but to avoid overflows, scale by d/c if c>=d, else c/d
Part scale; // <= 1.0
RealFlags flags;
bool cGEd{that.re_.ABS().Compare(that.im_.ABS()) != Relation::Less};
if (cGEd) {
scale = that.im_.Divide(that.re_, rounding).AccumulateFlags(flags);
} else {
scale = that.re_.Divide(that.im_, rounding).AccumulateFlags(flags);
}
Part den;
if (cGEd) {
Part dS{scale.Multiply(that.im_, rounding).AccumulateFlags(flags)};
den = dS.Add(that.re_, rounding).AccumulateFlags(flags);
} else {
Part cS{scale.Multiply(that.re_, rounding).AccumulateFlags(flags)};
den = cS.Add(that.im_, rounding).AccumulateFlags(flags);
}
Part aS{scale.Multiply(re_, rounding).AccumulateFlags(flags)};
Part bS{scale.Multiply(im_, rounding).AccumulateFlags(flags)};
Part re1, im1;
if (cGEd) {
re1 = re_.Add(bS, rounding).AccumulateFlags(flags);
im1 = im_.Subtract(aS, rounding).AccumulateFlags(flags);
} else {
re1 = aS.Add(im_, rounding).AccumulateFlags(flags);
im1 = bS.Subtract(re_, rounding).AccumulateFlags(flags);
}
Part re{re1.Divide(den, rounding).AccumulateFlags(flags)};
Part im{im1.Divide(den, rounding).AccumulateFlags(flags)};
return {Complex{re, im}, flags};
}
template <typename R> std::string Complex<R>::DumpHexadecimal() const {
std::string result{'('};
result += re_.DumpHexadecimal();
result += ',';
result += im_.DumpHexadecimal();
result += ')';
return result;
}
template <typename R>
llvm::raw_ostream &Complex<R>::AsFortran(llvm::raw_ostream &o, int kind) const {
re_.AsFortran(o << '(', kind);
im_.AsFortran(o << ',', kind);
return o << ')';
}
template class Complex<Real<Integer<16>, 11>>;
template class Complex<Real<Integer<16>, 8>>;
template class Complex<Real<Integer<32>, 24>>;
template class Complex<Real<Integer<64>, 53>>;
template class Complex<Real<Integer<80>, 64>>;
template class Complex<Real<Integer<128>, 113>>;
} // namespace Fortran::evaluate::value