leansdr::gf2n< Te, N, ALPHA, TRUNCP > Struct Template Reference

#include <discrmath.h>

Public Types
typedef Te	element

Public Member Functions
	gf2n ()
Te	add (Te x, Te y)
Te	sub (Te x, Te y)
Te	mul (Te x, Te y)
Te	div (Te x, Te y)
Te	inv (Te x)
Te	exp (Te x)
Te	log (Te x)

Static Public Attributes
static const Te	alpha = ALPHA

Private Attributes
Te	lut_exp [(1<< N) *2]
Te	lut_log [1<< N]

Detailed Description

template<typename Te, int N, Te ALPHA, Te TRUNCP>
struct leansdr::gf2n< Te, N, ALPHA, TRUNCP >

Definition at line 218 of file discrmath.h.

Member Typedef Documentation

element

template<typename Te, int N, Te ALPHA, Te TRUNCP>

typedef Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::element

Definition at line 220 of file discrmath.h.

Constructor & Destructor Documentation

gf2n()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

leansdr::gf2n< Te, N, ALPHA, TRUNCP >::gf2n ( )

inline

Definition at line 222 of file discrmath.h.

    {
        if (ALPHA != 2)
            fail("alpha!=2 not implemented");
        // Precompute log and exp tables.
        Te alpha_i = 1; // ALPHA^0
        for (int i = 0; i < (1 << N); ++i)
        {
            lut_exp[i] = alpha_i;                  // ALPHA^i
            lut_exp[((1 << N) - 1) + i] = alpha_i; // Wrap to avoid modulo 2^N-1
            lut_log[alpha_i] = i;
            bool overflow = alpha_i & (1 << (N - 1));
            alpha_i <<= 1;               // Multiply by alpha=[X] i.e. increase degrees
            alpha_i &= ~((~(Te)0) << N); // In case Te is wider than N bits
            if (overflow)
                alpha_i ^= TRUNCP; // Modulo P iteratively
        }
    }

Member Function Documentation

add()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::add ( Te  x, Te  y  )

inline

Definition at line 240 of file discrmath.h.

{ return x ^ y; } // Addition modulo 2

div()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::div ( Te  x, Te  y  )

inline

Definition at line 248 of file discrmath.h.

    {
        if (!x)
            return 0;
        return lut_exp[lut_log[x] + ((1 << N) - 1) - lut_log[y]];
    }

exp()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::exp ( Te  x )

inline

Definition at line 258 of file discrmath.h.

{ return lut_exp[x]; }

inv()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::inv ( Te  x )

inline

Definition at line 254 of file discrmath.h.

    {
        return lut_exp[((1 << N) - 1) - lut_log[x]];
    }

log()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::log ( Te  x )

inline

Definition at line 259 of file discrmath.h.

{ return lut_log[x]; }

mul()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::mul ( Te  x, Te  y  )

inline

Definition at line 242 of file discrmath.h.

    {
        if (!x || !y)
            return 0;
        return lut_exp[lut_log[x] + lut_log[y]];
    }

sub()

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::sub ( Te  x, Te  y  )

inline

Definition at line 241 of file discrmath.h.

{ return x ^ y; } // Subtraction modulo 2

Member Data Documentation

alpha

template<typename Te, int N, Te ALPHA, Te TRUNCP>

const Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::alpha = ALPHA

static

Definition at line 221 of file discrmath.h.

lut_exp

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::lut_exp[(1<< N) *2]

private

Definition at line 262 of file discrmath.h.

lut_log

template<typename Te, int N, Te ALPHA, Te TRUNCP>

Te leansdr::gf2n< Te, N, ALPHA, TRUNCP >::lut_log[1<< N]

private

Definition at line 263 of file discrmath.h.

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The documentation for this struct was generated from the following file:

• plugins/channelrx/demoddatv/leansdr/discrmath.h