numerical.h

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#pragma once

#include <stdbool.h>

typedef uint64_t seed_type;

typedef struct _numerical_state {
    seed_type seed;       
    double gset;          
    bool iset;        
} numerical_state_t;

void numerical_init(void);


// without this stuff dijkstra on thousands of nodes would probably fail horribly:
// this is needed in order to lose less precision on hundreds of double additions

struct _sum_helper_t{
    double sum;
    double crt;
};

double          NeumaierSum (unsigned cnt, double addendums[cnt]);
struct _sum_helper_t    PartialNeumaierSum(struct _sum_helper_t sh, double addendum);

#define ValueSumHelper(a) (a.crt + a.sum)

#define CmpSumHelpers(a, b) ({\
    double __a_s = a.sum + a.crt;\
    double __b_s = b.sum + b.crt;\
    (__a_s > __b_s) - (__b_s > __a_s);\
})