From d2a8386f675fc01216c29e96d35518789b25965b Mon Sep 17 00:00:00 2001
From: Sam Moore <matches@ucc.asn.au>
Date: Mon, 7 Jul 2014 09:49:20 +0800
Subject: [PATCH] Arbint subtraction/addition deal with borrow/carry correctly,
maybe
Eventually they will be right.
This still doesn't fix the wierd bezier bug or the growing digits really fast (exponential?). I suspect the former is related
to pow(Rational<Arbint>, Rational<Arbint>) and the latter probably makes sense if you do the theory (considering how fast Rational<int64_t> overflowed).
---
src/arbint.cpp | 64 ++++++++++++++++++++-----------------------
src/main.cpp | 5 +---
src/tests/realops.cpp | 2 +-
3 files changed, 31 insertions(+), 40 deletions(-)
diff --git a/src/arbint.cpp b/src/arbint.cpp
index 12cf18d..df6da8d 100644
--- a/src/arbint.cpp
+++ b/src/arbint.cpp
@@ -203,19 +203,28 @@ Arbint & Arbint::operator-=(const Arbint & sub)
Arbint & Arbint::AddBasic(const Arbint & add)
{
+ // Add any leading zeros to this number
while (m_digits.size() < add.m_digits.size())
{
-
- Debug("Size is %u, add's size is %u", m_digits.size(), add.m_digits.size());
GrowDigit(0L);
}
//m_digits.resize(add.m_digits.size()+1,0L);
digit_t carry = add_digits((digit_t*)m_digits.data(),
(digit_t*)add.m_digits.data(), add.m_digits.size());
+
+ // This number had more digits but there is a carry left over
+ if (carry != 0L && m_digits.size() > add.m_digits.size())
+ {
+ vector<digit_t> carry_digits(m_digits.size() - add.m_digits.size(), 0L);
+ carry_digits[0] = carry;
+ carry = add_digits((digit_t*)m_digits.data()+add.m_digits.size(),
+ (digit_t*)carry_digits.data(), m_digits.size()-add.m_digits.size());
+ }
+
+ // There is still a carry left over
if (carry != 0L)
{
- Debug("Grow carry %lu", carry);
GrowDigit(carry);
}
Shrink();
@@ -224,51 +233,36 @@ Arbint & Arbint::AddBasic(const Arbint & add)
Arbint & Arbint::SubBasic(const Arbint & sub)
{
- bool fith = false;
+ // Add leading zeros
while (sub.m_digits.size() > m_digits.size())
{
- fith = false;
GrowDigit(0L);
}
- if (fith)
- {
- Debug("START sub was %c%s, I am %c%s", SignChar(), sub.DigitStr().c_str(), SignChar(), DigitStr().c_str());
- }
+ // Do subtraction on digits
digit_t borrow = sub_digits((digit_t*)m_digits.data(),
(digit_t*)sub.m_digits.data(), sub.m_digits.size());
-
- if (fith)
+
+ // This number had more digits but there is a borrow left over
+ if (borrow != 0L && m_digits.size() > sub.m_digits.size())
{
- Debug("SUB_DIGITS -> sub was %c%s, I am %c%s, borrow is %lu", SignChar(), sub.DigitStr().c_str(), SignChar(), DigitStr().c_str(), borrow);
+ vector<digit_t> borrow_digits(m_digits.size()-sub.m_digits.size(), 0L);
+ borrow_digits[0] = borrow;
+ borrow = sub_digits((digit_t*)m_digits.data()+sub.m_digits.size(),
+ (digit_t*)borrow_digits.data(), m_digits.size()-sub.m_digits.size());
}
-
- //TODO: Write ASM to do this bit?
+
+ // borrow is still set => number is negative
if (borrow != 0L)
{
- if (sub.m_digits.size() < m_digits.size())
- {
- m_digits[m_digits.size()-1] -= borrow;
- }
- else
- {
- m_sign = !m_sign;
- for (unsigned i = 0; i < m_digits.size(); ++i)
- m_digits[i] = (~m_digits[i]);
- vector<digit_t> one_digits(m_digits.size(), 0L);
- one_digits[0] = 1L;
- add_digits((digit_t*)m_digits.data(), (digit_t*)one_digits.data(), m_digits.size());
- }
- }
- if (fith)
- {
- Debug("END -> sub was %c%s, I am %c%s", sub.SignChar(), sub.DigitStr().c_str(), SignChar(), DigitStr().c_str());
+ m_sign = !m_sign;
+ for (unsigned i = 0; i < m_digits.size(); ++i)
+ m_digits[i] = (~m_digits[i]);
+ vector<digit_t> one_digits(m_digits.size(), 0L);
+ one_digits[0] = 1L;
+ add_digits((digit_t*)m_digits.data(), (digit_t*)one_digits.data(), m_digits.size());
}
Shrink();
- if (fith)
- {
- Debug("SHRUNK -> sub was %c%s, I am %c%s", sub.SignChar(), sub.DigitStr().c_str(), SignChar(), DigitStr().c_str());
- }
return *this;
}
diff --git a/src/main.cpp b/src/main.cpp
index 194ef04..91e362c 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -97,10 +97,7 @@ int main(int argc, char ** argv)
//doc.Add(BEZIER, Rect(0.2+x-4.0, 0.2+y-4.0, 0.6,0.6), (x^y)%3);
}
}
- Debug("Make rect");
- doc.Add(RECT_OUTLINE, Rect(0.1,0.1,0.8,0.8), 0);
- Debug("Made rect");
-
+ doc.Add(BEZIER, Rect(0.1,0.1,0.8,0.8), 0);
}
Debug("Start!");
Rect bounds(b[0],b[1],b[2],b[3]);
diff --git a/src/tests/realops.cpp b/src/tests/realops.cpp
index 4ac54ff..83a5241 100644
--- a/src/tests/realops.cpp
+++ b/src/tests/realops.cpp
@@ -22,7 +22,7 @@ int main(int argc, char ** argv)
unsigned failures = 0;
for (unsigned i = 0; i < TEST_CASES; ++i)
{
- Debug("Test %u of %u", i, TEST_CASES);
+ //Debug("Test %u of %u", i, TEST_CASES);
double da = (double)(rand() + 1) / (double)(rand() + 1);
double db = (double)(rand() + 1) / (double)(rand() + 1);
--
2.20.1