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added functions for modulo calculations

This commit is contained in:
Martchus 2016-01-27 00:15:01 +01:00
parent 3c9f95059e
commit 73436d4593
2 changed files with 53 additions and 3 deletions
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52
math/math.cpp
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@ -9,7 +9,8 @@
*/
/*!
* Returns a pseudo random number between \a lowerbounds and \a upperbounds.
* \brief Returns a pseudo random number between \a lowerbounds and \a upperbounds.
* \remarks Might be removed since std::uniform_int_distribution does the same.
*/
int MathUtilities::random(int lowerbounds, int upperbounds)
{
@ -18,7 +19,7 @@ int MathUtilities::random(int lowerbounds, int upperbounds)
}
/*!
* Returns the digitsum of the given \a number using the specified \a base.
* \brief Returns the digitsum of the given \a number using the specified \a base.
*/
int MathUtilities::digitsum(int number, int base)
{
@ -31,7 +32,7 @@ int MathUtilities::digitsum(int number, int base)
}
/*!
* Returns the factorial of the given \a number;
* \brief Returns the factorial of the given \a number.
*/
int MathUtilities::factorial(int number)
{
@ -41,3 +42,48 @@ int MathUtilities::factorial(int number)
}
return res;
}
/*!
* \brief Computes \a base power \a exponent modulo \a module.
*/
uint64 powerModulo(const uint64 base, const uint64 exponent, const uint64 module)
{
uint64 res = 1;
for(uint64 mask = 0x8000000000000000; mask; mask >>= 1) {
if(mask & exponent) {
res *= base;
}
if(mask != 1) {
res *= res;
}
res %= module;
}
return res;
}
/*!
* \brief Computes the inverse of \a number modulo \a module.
*/
int64 inverseModulo(int64 number, int64 module)
{
int64 y1 = 0, y2 = 1, tmp;
while(number != 1) {
tmp = y1 - (module / number) * y2;
y1 = y2;
y2 = tmp;
tmp = module % number;
module = number;
number = tmp;
}
return y2;
}
/*!
* \brief Computes the order of \a number modulo \a module.
*/
uint64 orderModulo(const uint64 number, const uint64 module)
{
uint64 order = 1;
for(; powerModulo(number, order, module) != 1; ++order);
return order;
}

4
math/math.h
View File

@ -2,12 +2,16 @@
#define MATHUTILITIES_H
#include "../application/global.h"
#include "../conversion/types.h"
namespace MathUtilities {
LIB_EXPORT int random(int lowerbounds, int upperbounds);
LIB_EXPORT int digitsum(int number, int base = 10);
LIB_EXPORT int factorial(int number);
LIB_EXPORT uint64 powerModulo(uint64 base, uint64 expontent, uint64 module);
LIB_EXPORT int64 inverseModulo(int64 number, int64 module);
LIB_EXPORT uint64 orderModulo(uint64 number, uint64 module);
}