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61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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#include "runtime.h"
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typedef struct Complex128 Complex128;
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void
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·complex128div(Complex128 n, Complex128 d, Complex128 q)
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{
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int32 ninf, dinf, nnan, dnan;
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float64 a, b, ratio, denom;
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// Special cases as in C99.
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ninf = isInf(n.real, 0) || isInf(n.imag, 0);
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dinf = isInf(d.real, 0) || isInf(d.imag, 0);
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nnan = !ninf && (isNaN(n.real) || isNaN(n.imag));
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dnan = !dinf && (isNaN(d.real) || isNaN(d.imag));
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if(nnan || dnan) {
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q.real = NaN();
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q.imag = NaN();
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} else if(ninf && !dinf && !dnan) {
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q.real = Inf(0);
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q.imag = Inf(0);
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} else if(!ninf && !nnan && dinf) {
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q.real = 0;
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q.imag = 0;
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} else if(d.real == 0 && d.imag == 0) {
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if(n.real == 0 && n.imag == 0) {
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q.real = NaN();
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q.imag = NaN();
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} else {
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q.real = Inf(0);
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q.imag = Inf(0);
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}
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} else {
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// Standard complex arithmetic, factored to avoid unnecessary overflow.
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a = d.real;
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if(a < 0)
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a = -a;
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b = d.imag;
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if(b < 0)
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b = -b;
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if(a <= b) {
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ratio = d.real/d.imag;
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denom = d.real*ratio + d.imag;
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q.real = (n.real*ratio + n.imag) / denom;
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q.imag = (n.imag*ratio - n.real) / denom;
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} else {
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ratio = d.imag/d.real;
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denom = d.imag*ratio + d.real;
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q.real = (n.imag*ratio + n.real) / denom;
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q.imag = (n.imag - n.real*ratio) / denom;
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}
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}
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FLUSH(&q);
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}
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