85 lines
3.1 KiB
C++
85 lines
3.1 KiB
C++
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// Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "complex.h"
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namespace Fortran::evaluate::value {
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template<typename R>
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ValueWithRealFlags<Complex<R>> Complex<R>::Add(const Complex &that) const {
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RealFlags flags;
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Part reSum{re_.Add(that.re_).AccumulateFlags(flags)};
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Part imSum{im_.Add(that.im_).AccumulateFlags(flags)};
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return {Complex{reSum, imSum}, flags};
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}
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template<typename R>
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ValueWithRealFlags<Complex<R>> Complex<R>::Subtract(const Complex &that) const {
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RealFlags flags;
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Part reDiff{re_.Subtract(that.re_).AccumulateFlags(flags)};
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Part imDiff{im_.Subtract(that.im_).AccumulateFlags(flags)};
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return {Complex{reDiff, imDiff}, flags};
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}
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template<typename R>
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ValueWithRealFlags<Complex<R>> Complex<R>::Multiply(const Complex &that) const {
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// (a + ib)*(c + id) -> ac - bd + i(ad + bc)
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RealFlags flags;
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Part ac{re_.Multiply(that.re_).AccumulateFlags(flags)};
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Part bd{im_.Multiply(that.im_).AccumulateFlags(flags)};
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Part ad{re_.Multiply(that.im_).AccumulateFlags(flags)};
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Part bc{im_.Multiply(that.re_).AccumulateFlags(flags)};
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Part acbd{ac.Subtract(bd).AccumulateFlags(flags)};
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Part adbc{ad.Add(bc).AccumulateFlags(flags)};
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return {Complex{acbd, adbc}, flags};
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}
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template<typename R>
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ValueWithRealFlags<Complex<R>> Complex<R>::Divide(const Complex &that) const {
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// (a + ib)/(c + id) -> [(a+ib)*(c-id)] / [(c+id)*(c-id)]
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// -> [ac+bd+i(bc-ad)] / (cc+dd)
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// -> ((ac+bd)/(cc+dd)) + i((bc-ad)/(cc+dd))
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// but to avoid overflows, scale by d/c if c>=d, else c/d
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Part scale; // <= 1.0
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RealFlags flags;
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bool cGEd{that.re_.ABS().Compare(that.im_.ABS()) != Relation::Less};
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if (cGEd) {
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scale = that.im_.Divide(that.re_).AccumulateFlags(flags);
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} else {
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scale = that.re_.Divide(that.im_).AccumulateFlags(flags);
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}
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Part den;
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if (cGEd) {
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Part dS{scale.Multiply(that.im_).AccumulateFlags(flags)};
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den = dS.Add(that.re_).AccumulateFlags(flags);
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} else {
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Part cS{scale.Multiply(that.re_).AccumulateFlags(flags)};
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den = cS.Add(that.im_).AccumulateFlags(flags);
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}
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Part aS{scale.Multiply(re_).AccumulateFlags(flags)};
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Part bS{scale.Multiply(im_).AccumulateFlags(flags)};
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Part re1, im1;
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if (cGEd) {
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re1 = re_.Add(bS).AccumulateFlags(flags);
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im1 = im_.Subtract(aS).AccumulateFlags(flags);
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} else {
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re1 = aS.Add(im_).AccumulateFlags(flags);
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im1 = bS.Subtract(re_).AccumulateFlags(flags);
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}
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Part re{re1.Divide(den).AccumulateFlags(flags)};
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Part im{im1.Divide(den).AccumulateFlags(flags)};
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return {Complex{re, im}, flags};
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}
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} // namespace Fortran::evaluate::value
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