Simple_Lib.c File Reference

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Functions
void	simple_init (void)
double	simple_compute (double x)

Variables
static double	comp_value
static long long int	total_iter_cnt
static long long int	low_wtrmrk
static long long int	high_wtrmrk
static papi_handle_t	handle
static const char *	ev_names [4]

Function Documentation

simple_compute()

double simple_compute

(

double

x

)

Definition at line 45 of file Simple_Lib.c.

                               {
    double sum = 0.0;
    int lcl_iter = 0;
 
    if( x > 1.0 )
        x = 1.0/x;
    if( x < 0.000001 )
        x += 0.3579;
 
    while( 1 ){
        double y,x2,x3,x4;
        lcl_iter++;
 
        // Compute a function with range [0:1] so we can iterate
        // multiple times without diverging or creating FP exceptions.
        x2 = x*x;
        x3 = x2*x;
        x4 = x2*x2;
        y = 42.53*x4 -67.0*x3 +25.0*x2 +x/2.15;
        y = y*y;
        if( y < 0.01 )
            y = 0.5-y;
 
        // Now set the next x to be the current y, so we can iterate again.
        x = y;
 
        // Add y to sum unconditionally
        sum += y;
 
        if( y < 0.1 ){
            low_wtrmrk++;
            continue;
        }
 
        if( y > 0.9 ){
            high_wtrmrk++;
            continue;
        }
 
        // Only add y to comp_value if y is between the low and high watermarks.
        comp_value += y;
 
        // If some condition is met, terminate the loop
        if( 0.61 < y && y < 0.69 )
            break;
    }
    total_iter_cnt += lcl_iter;
 
    return sum;
}

simple_init()

void simple_init

(

void

)

Definition at line 25 of file Simple_Lib.c.

                      {
 
    // Initialize library specific variables
    comp_value = 0.0;
    total_iter_cnt = 0;
    low_wtrmrk = 0;
    high_wtrmrk = 0;
 
    // Initialize PAPI SDEs
    handle = papi_sde_init("Simple");
    papi_sde_register_counter(handle, ev_names[0], PAPI_SDE_RO|PAPI_SDE_INSTANT, PAPI_SDE_double, &comp_value);
    papi_sde_register_counter(handle, ev_names[1], PAPI_SDE_RO|PAPI_SDE_DELTA,   PAPI_SDE_long_long, &total_iter_cnt);
    papi_sde_register_counter(handle, ev_names[2], PAPI_SDE_RO|PAPI_SDE_DELTA,   PAPI_SDE_long_long, &low_wtrmrk);
    papi_sde_register_counter(handle, ev_names[3], PAPI_SDE_RO|PAPI_SDE_DELTA,   PAPI_SDE_long_long, &high_wtrmrk);
 
    return;
}

Variable Documentation

comp_value

double comp_value

static

Definition at line 13 of file Simple_Lib.c.

ev_names

const char* ev_names[4]

static

Initial value:

= {
    "COMPUTED_VALUE",
    "TOTAL_ITERATIONS",
    "LOW_WATERMARK_REACHED",
    "HIGH_WATERMARK_REACHED"
}

Definition at line 17 of file Simple_Lib.c.

handle

papi_handle_t handle

static

Definition at line 15 of file Simple_Lib.c.

high_wtrmrk

long long int high_wtrmrk

static

Definition at line 14 of file Simple_Lib.c.

low_wtrmrk

long long int low_wtrmrk

static

Definition at line 14 of file Simple_Lib.c.

total_iter_cnt

long long int total_iter_cnt

static

Definition at line 14 of file Simple_Lib.c.