view Discovery/Src/buehlmann.c @ 232:f0069f002c55 div-fixes-4-1

Bugfix: make date/time setting work over reboots Setting the time/date over the UART interface or by the menu, seems to work, but a reboot of the RTE brings back strange, seemingly random, time. The reason for this is rather simple. In the settings, a time is stored, based on some flawed logic, and that time was restored on reboot. There is no reason to store any time, when the moment of restoring it is unrelated in time. So, the fix is simple: do not set time (in the RTC) based on some time from the past. The whole idea of a RTC is that it does preserve the time for you, as long its powered. Any attempt to do things better using stored time data is futile (and nonsense). And while working on his, also kick out some useless code from the RTE. There is no reason to initialize the time on the RTC to some random time/date in the past. A zero data/time is as good and any random date. Signed-off-by: Jan Mulder <jlmulder@xs4all.nl>
author Jan Mulder <jlmulder@xs4all.nl>
date Wed, 03 Apr 2019 21:11:56 +0200
parents ceecabfddb57
children ff0d23625cd5
line wrap: on
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/*	getrennte Gase f�r die verschiedenen Modi
		um Gaswechsel Eintr�ge zu vereinfachen
		das heisst:
		oc == bailout in cc mode
*/

/* Konvention:
float extExample_variable_can_be_used_with_extern;
*/

#include <string.h>
//#include "arm_math.h"
#include <math.h>
#include <stdbool.h>
#include "buehlmann.h"
#include "decom.h"


extern const float buehlmann_N2_a[];
extern const float buehlmann_N2_b[];
extern const float buehlmann_He_a[];
extern const float buehlmann_He_b[];


/*
typedef struct
{
	float *pointer_array_tissue_nitrogen_bar;
	float *pointer_array_tissue_helium_bar;
	char gf_value;

	float output_ceiling_ambient_bar_or_input;
	_Bool output_ceiling_tolerated_if_ceiling_used_as_input;
}		tissue_test_tolerance_struct;
*/
typedef struct
{
	float depth;
	int id;
} SStop;

#define DECO_STOPS_MAX_TTS_CALCULATON_IN_SECONDS 59940 // 999 minuten; before: 18000 // 5(h) * 60(min) * 60 sec = 18000 sec
#define DECO_STOPS_MAX_TTS_FOR_EVERY_SECOND_CALC_IN_SECONDS 7200
#define NINETY_NINE_MINUTES_IN_SECONDS 59940

# define PRESSURE_TEN_METER 1.0f
# define PRESSURE_THREE_METER 0.333334f
# define PRESSURE_150_CM 0.15f
# define PRESSURE_HALF_METER 0.05f
/*
# define PRESSURE_150_CM_MBAR 150
# define PRESSURE_TWO_M_MBAR 200
# define PRESSURE_FIVE_M_MBAR 500
# define PRESSURE_TEN_M_MBAR 1000
# define PRESSURE_120_METER 12.0
*/
/*
_____________________________________________________________
*/


void buehlmann_backup_and_restore(_Bool backup_restore_otherwise);
float tissue_tolerance(void);
void ambient_bar_to_deco_stop_depth_bar(float ceiling);
int ascend_with_all_gaschanges(float pressure_decrease);
float next_stop_depth_input_is_actual_stop_id(int actual_id);
float get_gf_at_pressure(float pressure);
void buehlmann_calc_ndl(void);
_Bool dive1_check_deco(void);
uint8_t buehlmann_tissue_test_tolerance(float depth_in_bar_absolute);

/*
_____________________________________________________________
*/

SDecoinfo gDecotable;
float gSurface_pressure_bar;
float gPressure;
int gGas_id;
float gTTS;
float gTissue_nitrogen_bar[16];
float gTissue_helium_bar[16];
float gGF_value;
float gCNS;
//float gMax_ceiling_bar = 0;
int gNDL;


//SLifeData *pLifeData;
SDiveSettings *pBuDiveSettings;
SDecoinfo* pDecolistBuehlmann;
//signed char gGaschange_decreasing_depth_gas_id[BUEHLMANN_STRUCT_MAX_GASES];
float gGF_low_depth_bar;
SStop gStop;

void buehlmann_init(void)
{
  //gMax_ceiling_bar = 0;
}

void buehlmann_backup_and_restore(_Bool backup_restore_otherwise)
{
	static float pressure;
	static float gas_id;
	static float tts;
	static float tissue_nitrogen_bar[16];
	static float tissue_helium_bar[16];
	static float gf_value;
	static int ndl;
	static float cns;

	if(backup_restore_otherwise)
	{
		pressure = gPressure;
		gas_id = gGas_id;
		tts = gTTS;
		gf_value = gGF_value;
		ndl = gNDL;
		cns = gCNS;
		memcpy(tissue_nitrogen_bar, gTissue_nitrogen_bar, (4*16));
		memcpy(tissue_helium_bar, gTissue_helium_bar, (4*16));
	}
	else
	{
		gPressure = pressure;
		gGas_id = gas_id;
		gTTS = tts;
		gGF_value = gf_value;
		gNDL = ndl;
		gCNS = cns;
		memcpy(gTissue_nitrogen_bar, tissue_nitrogen_bar, (4*16));
		memcpy(gTissue_helium_bar, tissue_helium_bar, (4*16));
	}

}
/*void buehlmann__test__saturate_tissues(SBuehlmann *pInput,  int seconds)
{
	pBuehlmann = pInput;
	pInput->dive_time_seconds += seconds;
	// internal copying
	gSurface_pressure_bar = pBuehlmann->pressure_surface_bar;

	gPressure = pBuehlmann->pressure_ambient_bar;
	gGas_id = pBuehlmann->actual_gas_id;
	memcpy(gTissue_nitrogen_bar, pBuehlmann->tissue_nitrogen_bar, (4*16));
	memcpy(gTissue_helium_bar, pBuehlmann->tissue_helium_bar, (4*16));

	tissues_exposure_at_gPressure_seconds(seconds);

	memcpy(pBuehlmann->tissue_nitrogen_bar, gTissue_nitrogen_bar, (4*16));
	memcpy(pBuehlmann->tissue_helium_bar, gTissue_helium_bar, (4*16));
}*/

float buehlmann_get_gCNS(void)
{
	return gCNS;
}

void buehlmann_calc_deco(SLifeData* pLifeData, SDiveSettings * pDiveSettings, SDecoinfo * pDecoInfo)
{
	float ceiling;
	int ascend_time;
	int tts_seconds;
	float pressure_delta;
	float next_depth;
	_Bool deco_reached = false;
//	tissue_test_tolerance_struct tolerance_data;
	unsigned short *stoplist;
	int i;
	
   // decom_CreateGasChangeList(pDiveSettings, pLifeData);

	gCNS = 0;
  pDecoInfo->output_time_to_surface_seconds = 0;
	pDecoInfo->output_ndl_seconds = 0;
	for(int i=0;i<DECOINFO_STRUCT_MAX_STOPS;i++)
	{
		pDecoInfo->output_stop_length_seconds[i] = 0;
	}
	/* make input available global*/
	pBuDiveSettings = pDiveSettings;

  pDecolistBuehlmann = pDecoInfo;
	/* internal copying */
	gSurface_pressure_bar = pLifeData->pressure_surface_bar;

	gPressure = pLifeData->pressure_ambient_bar;
	gGas_id = 0;
	memcpy(gTissue_nitrogen_bar, pLifeData->tissue_nitrogen_bar, (4*16));
	memcpy(gTissue_helium_bar, pLifeData->tissue_helium_bar, (4*16));
	gGF_value = ((float)pBuDiveSettings->gf_low) / 100.0f;
	
	//
	memcpy(&gDecotable, pDecolistBuehlmann, sizeof(SDecoinfo));
	stoplist = gDecotable.output_stop_length_seconds;


  if(pLifeData->dive_time_seconds < 60)
    return;
	/* coupling */

	/* functions */

	// clean stop list
	for(i = 0; i < DECOINFO_STRUCT_MAX_STOPS; i++)
		stoplist[i] = 0;
	gTTS = 0;
	gNDL = 0;

  if(pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero >= (gPressure - PRESSURE_150_CM))
  {
    deco_reached = true;
  }


//ascend_with_all_gaschanges(gPressure - gSurface_pressure_bar);
	gGF_value = ((float)pBuDiveSettings->gf_high) / 100.0f;
	//iling = tissue_tolerance();
	// includes backup for gGF_value
	// NDL
	buehlmann_backup_and_restore(true); // includes backup for gGF_value
	if(!dive1_check_deco() )
	{
	  buehlmann_backup_and_restore(false);
		// no deco
		pDecolistBuehlmann->output_time_to_surface_seconds = 0;
		for(i = 0; i < DECOINFO_STRUCT_MAX_STOPS; i++)
			pDecolistBuehlmann->output_stop_length_seconds[i] = 0;
		// calc NDL
		buehlmann_calc_ndl();
		pDecolistBuehlmann->output_ndl_seconds = gNDL;
		return;
	}
	buehlmann_backup_and_restore(false);
	pDecolistBuehlmann->output_ndl_seconds = 0;

  gGF_value = get_gf_at_pressure(gPressure);
	//current ceiling at actual position
	ceiling = tissue_tolerance();
	//if(ceiling < pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero)
		//ambient_bar_to_deco_stop_depth_bar(pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero);
	//else
  ambient_bar_to_deco_stop_depth_bar(ceiling);

	// set the base for all upcoming parameters
	ceiling = gStop.depth + gSurface_pressure_bar;
	tts_seconds = 0;

	// modify parameters if there is ascend or parameter fine adjustment
	if(ceiling < (gPressure - PRESSURE_150_CM)) // more than 1.5 meter below ceiling
	{
		// ascend within 10 mtr to GF_low // speed 12 mtr/min -> 50 sec / 10 mtr;  15 sec / 3 mtr.
		if(ceiling < (gPressure - PRESSURE_TEN_METER) )
		{ do {
				ascend_time = ascend_with_all_gaschanges(PRESSURE_TEN_METER);
				tts_seconds += ascend_time;
				ceiling = tissue_tolerance();
				if(tts_seconds > DECO_STOPS_MAX_TTS_CALCULATON_IN_SECONDS)
			{
				/* pInput == pBuehlmann */
				pDecolistBuehlmann->output_time_to_surface_seconds = NINETY_NINE_MINUTES_IN_SECONDS;
				return;// NINETY_NINE_MINUTES_IN_SECONDS;
			}
			} while ((ascend_time > 0 ) && ((gPressure - PRESSURE_TEN_METER ) > gSurface_pressure_bar) && (ceiling < (gPressure - PRESSURE_TEN_METER)));
		}
		do {
			buehlmann_backup_and_restore(true);
			ascend_time = ascend_with_all_gaschanges(PRESSURE_THREE_METER);
			tts_seconds += ascend_time;
			ceiling = tissue_tolerance();
			if(tts_seconds > DECO_STOPS_MAX_TTS_CALCULATON_IN_SECONDS)
			{
				/* pInput == pBuehlmann */
				pDecolistBuehlmann->output_time_to_surface_seconds = NINETY_NINE_MINUTES_IN_SECONDS;
				return;// NINETY_NINE_MINUTES_IN_SECONDS;
			}
			ambient_bar_to_deco_stop_depth_bar(ceiling);
		} while ((ascend_time > 0 ) &&  ((gStop.depth + gSurface_pressure_bar) < gPressure));

		if(gStop.depth + gSurface_pressure_bar > gPressure)
		{
			gPressure += PRESSURE_THREE_METER;
			buehlmann_backup_and_restore(false);
			tts_seconds -= ascend_time;
		}
    // calculate first stop based on tissue saturation within 10 meters of stop
    //ambient_bar_to_deco_stop_depth_bar(ceiling);
	}
	else
	{
		// initial values, upper code might not be executed (is within 150 cm)
	}




  if(ceiling > gSurface_pressure_bar)
  {

    ceiling = gStop.depth + gSurface_pressure_bar;
    // ascend the last meters to first stop (especially consider any gas changes around)
    pressure_delta = gPressure - ceiling;
    ascend_time = (int)ceil(pressure_delta * 50.0f);
    tts_seconds += ascend_with_all_gaschanges(pressure_delta);
  }
	// NDL check
	if(ceiling <= gSurface_pressure_bar)
	{
		/* pInput == pBuehlmann  same pointer*/
		// NDL with GF_low
		pDecolistBuehlmann->output_time_to_surface_seconds = 0;
		return;
	}
  if(ceiling >pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero)
    pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero = ceiling;

	// calc gf loop
	if(deco_reached)
		gGF_low_depth_bar = pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero - gSurface_pressure_bar;
	else
		gGF_low_depth_bar = ceiling - gSurface_pressure_bar;

	while(gStop.depth > 0)
	{
		do
		{
			next_depth = next_stop_depth_input_is_actual_stop_id(gStop.id);
      gGF_value = get_gf_at_pressure(next_depth + gSurface_pressure_bar);
			buehlmann_backup_and_restore(true);
			ascend_time = ascend_with_all_gaschanges(gStop.depth - next_depth);
			ceiling = tissue_tolerance();
			/* pre check actual limit */
			if(gDecotable.output_stop_length_seconds[gStop.id] >= 999*60)
			{
				tts_seconds -= 999*60 - gDecotable.output_stop_length_seconds[gStop.id];
				gDecotable.output_stop_length_seconds[gStop.id] = 999*60;
			}
			else
			/* more deco on the actual depth */
			if(ceiling > next_depth + gSurface_pressure_bar)
			{
				next_depth = -1;
				buehlmann_backup_and_restore(false);
				decom_tissues_exposure2(10, &pBuDiveSettings->decogaslist[gGas_id], gPressure,gTissue_nitrogen_bar,gTissue_helium_bar); // some seconds at least at each stop
				decom_oxygen_calculate_cns_exposure(10, &pBuDiveSettings->decogaslist[gGas_id], gPressure, &gCNS);
        gDecotable.output_stop_length_seconds[gStop.id] += 10;
        tts_seconds += 10;
			}
		} while(next_depth == -1);
    tts_seconds += ascend_time;
		gStop.depth = next_depth;
    for(i = gGas_id + 1; i < BUEHLMANN_STRUCT_MAX_GASES; i++)
    {
        if(pBuDiveSettings->decogaslist[i].change_during_ascent_depth_meter_otherwise_zero == 0)
            break;
        float pressureChange =  ((float)pBuDiveSettings->decogaslist[i].change_during_ascent_depth_meter_otherwise_zero) / 10;
        if(gStop.depth <= pressureChange + 0.00001f)
        {
            gGas_id = i;
        }
        else
        {
            break;
        }
    }
		gStop.id--;
	}

  gDecotable.output_time_to_surface_seconds = tts_seconds;
	memcpy(pDecolistBuehlmann, &gDecotable, sizeof(SDecoinfo));
}


float tissue_tolerance(void)
{
	float tissue_inertgas_saturation;
	float inertgas_a;
	float inertgas_b;
	float ceiling;
	float global_ceiling;
	int ci;

	global_ceiling = -1;

	for (ci = 0; ci < 16; ci++)
	{
		if(gTissue_helium_bar[ci] == 0)
		{
			tissue_inertgas_saturation = gTissue_nitrogen_bar[ci];
			//
			inertgas_a = buehlmann_N2_a[ci];
			inertgas_b = buehlmann_N2_b[ci];
		}
		else
		{
			tissue_inertgas_saturation =  gTissue_nitrogen_bar[ci] + gTissue_helium_bar[ci];
			//
			inertgas_a = ( ( buehlmann_N2_a[ci] *  gTissue_nitrogen_bar[ci]) + ( buehlmann_He_a[ci] * gTissue_helium_bar[ci]) ) / tissue_inertgas_saturation;
			inertgas_b = ( ( buehlmann_N2_b[ci] *  gTissue_nitrogen_bar[ci]) + ( buehlmann_He_b[ci] * gTissue_helium_bar[ci]) ) / tissue_inertgas_saturation;
		}
		//
		ceiling = (inertgas_b * ( tissue_inertgas_saturation - gGF_value * inertgas_a ) ) / (gGF_value - (inertgas_b * gGF_value) + inertgas_b);
		if(ceiling > global_ceiling)
			global_ceiling = ceiling;
	}
	return global_ceiling;
}

// hw 161121 for relative gradient
float tissue_tolerance_without_gf_correction(float *tissue_inertgas_saturation_output)
{
	float tissue_inertgas_saturation;
	float inertgas_a;
	float inertgas_b;
	float ceiling;
	float global_ceiling;
	int ci;

	global_ceiling = -1;

	for (ci = 0; ci < 16; ci++)
	{
		if(gTissue_helium_bar[ci] == 0)
		{
			tissue_inertgas_saturation = gTissue_nitrogen_bar[ci];
			//
			inertgas_a = buehlmann_N2_a[ci];
			inertgas_b = buehlmann_N2_b[ci];
		}
		else
		{
			tissue_inertgas_saturation =  gTissue_nitrogen_bar[ci] + gTissue_helium_bar[ci];
			//
			inertgas_a = ( ( buehlmann_N2_a[ci] *  gTissue_nitrogen_bar[ci]) + ( buehlmann_He_a[ci] * gTissue_helium_bar[ci]) ) / tissue_inertgas_saturation;
			inertgas_b = ( ( buehlmann_N2_b[ci] *  gTissue_nitrogen_bar[ci]) + ( buehlmann_He_b[ci] * gTissue_helium_bar[ci]) ) / tissue_inertgas_saturation;
		}
		//
		ceiling = inertgas_b * ( tissue_inertgas_saturation - inertgas_a );
		if(ceiling > global_ceiling)
		{
			global_ceiling = ceiling;
			if(tissue_inertgas_saturation_output)
			{
				*tissue_inertgas_saturation_output = tissue_inertgas_saturation;
			}
		}
	}
	return global_ceiling;
}


uint8_t buehlmann_tissue_test_tolerance(float depth_in_bar_absolute)
{
	float tissue_inertgas_saturation;
	float inertgas_a;
	float inertgas_b;
	float inertgas_tolerance;
	float gf_minus_1;

	gf_minus_1 = gGF_value - 1.0f;

	for (int ci = 0; ci < 16; ci++)
	{
		if(gTissue_helium_bar[ci] == 0)
		{
			tissue_inertgas_saturation = gTissue_nitrogen_bar[ci];
			//
			inertgas_a = buehlmann_N2_a[ci];
			inertgas_b = buehlmann_N2_b[ci];
		}
		else
		{
			tissue_inertgas_saturation =  gTissue_nitrogen_bar[ci] + gTissue_helium_bar[ci];
			//
			inertgas_a = ( ( buehlmann_N2_a[ci] *  gTissue_nitrogen_bar[ci]) + ( buehlmann_He_a[ci] * gTissue_helium_bar[ci]) ) / tissue_inertgas_saturation;
			inertgas_b = ( ( buehlmann_N2_b[ci] *  gTissue_nitrogen_bar[ci]) + ( buehlmann_He_b[ci] * gTissue_helium_bar[ci]) ) / tissue_inertgas_saturation;
		}
		//
		inertgas_tolerance = ( (gGF_value / inertgas_b - gf_minus_1) * depth_in_bar_absolute ) + ( gGF_value * inertgas_a );
		//
		if(inertgas_tolerance < tissue_inertgas_saturation)
			return 0;
	}
	return 1;
}


void ambient_bar_to_deco_stop_depth_bar(float ceiling)
{
	int i;

	ceiling -= gSurface_pressure_bar;

	if(ceiling <= 0)
	{
		gStop.depth = pBuDiveSettings->last_stop_depth_bar;
		gStop.id = 0;
		return;
	}


    //for(int i = 1; i < 10; i++)

	if((ceiling -  pBuDiveSettings->last_stop_depth_bar) <= 0)
	{
		gStop.depth =  pBuDiveSettings->last_stop_depth_bar;
		gStop.id = 0;
		return;
	}

	gStop.depth = pBuDiveSettings->input_second_to_last_stop_depth_bar;
	gStop.id = 1;
	ceiling -= pBuDiveSettings->input_second_to_last_stop_depth_bar;

	if(ceiling <= 0)
		return;

	for(i = 1; i < (DECOINFO_STRUCT_MAX_STOPS - 2); i++)
	{
		ceiling -= pBuDiveSettings->input_next_stop_increment_depth_bar;
		if(ceiling <= 0)
			break;
	}
	gStop.depth += i * pBuDiveSettings->input_next_stop_increment_depth_bar;
	gStop.id += i;
	return;
}

float next_stop_depth_input_is_actual_stop_id(int actual_id)
{
	if(actual_id == 0)
		return 0;

	if(actual_id == 1)
		return pBuDiveSettings->last_stop_depth_bar;

	actual_id -= 2;
	return pBuDiveSettings->input_second_to_last_stop_depth_bar + (actual_id * pBuDiveSettings->input_next_stop_increment_depth_bar);
}

int ascend_with_all_gaschanges(float pressure_decrease)
{
	float pressureTop, pressureTop_tmp, pressureBottom, pressureChange, ascendrate_in_seconds_for_one_bar, pressure_difference;
	int time_for_ascend = 0;
	int seconds;
	int i;

	ascendrate_in_seconds_for_one_bar = 60 * 10 / pBuDiveSettings->ascentRate_meterperminute;

	if(fabsf(gPressure - gSurface_pressure_bar) < PRESSURE_HALF_METER)
	{
		gPressure = gSurface_pressure_bar;
		return 0;
	}

	pressureTop = gPressure - pressure_decrease;
	if( gSurface_pressure_bar > pressureTop)
		pressureTop = gSurface_pressure_bar;
	pressureBottom = gPressure;
	seconds = 0;
    do{
        pressureTop_tmp = pressureTop;
        for(i = gGas_id + 1; i < BUEHLMANN_STRUCT_MAX_GASES; i++)
        {
            if(pBuDiveSettings->decogaslist[i].change_during_ascent_depth_meter_otherwise_zero == 0)
                break;
            pressureChange = gSurface_pressure_bar + ((float)pBuDiveSettings->decogaslist[i].change_during_ascent_depth_meter_otherwise_zero) / 10;
            if(pressureBottom <= pressureChange)
            {
                gGas_id = i;
            }
            else
            {
                 break;
            }

        }
        for(i = gGas_id + 1; i < BUEHLMANN_STRUCT_MAX_GASES; i++)
        {
            if(pBuDiveSettings->decogaslist[i].change_during_ascent_depth_meter_otherwise_zero == 0)
                break;
            pressureChange = gSurface_pressure_bar + ((float)pBuDiveSettings->decogaslist[i].change_during_ascent_depth_meter_otherwise_zero)/ 10;
            if((pressureChange < pressureBottom) && (pressureChange > pressureTop))
            {
                pressureTop_tmp = pressureChange;
            }
        }
        pressure_difference = pressureBottom - pressureTop_tmp;
        if(pressure_difference > 0.0001f)
        {
          time_for_ascend = (int)ceilf(pressure_difference * ascendrate_in_seconds_for_one_bar);
          decom_tissues_exposure_stage_schreiner(time_for_ascend, &pBuDiveSettings->decogaslist[gGas_id],
                                              pressureBottom, pressureTop_tmp, gTissue_nitrogen_bar, gTissue_helium_bar);
					decom_oxygen_calculate_cns_stage_SchreinerStyle(time_for_ascend,&pBuDiveSettings->decogaslist[gGas_id],
                                              pressureBottom, pressureTop_tmp, &gCNS);
        }
        pressureBottom = pressureTop_tmp;
        seconds += time_for_ascend;
    }while(pressureTop_tmp > pressureTop);
    gPressure = pressureTop;
	return seconds;
}


float get_gf_at_pressure(float pressure)
{
	float gfSteigung = 0.0f;

	if(gGF_low_depth_bar < 0)
			gGF_low_depth_bar = PRESSURE_THREE_METER; // just to prevent erratic behaviour if variable is not set

    gfSteigung = ((float)(pBuDiveSettings->gf_high - pBuDiveSettings->gf_low))/ gGF_low_depth_bar;


	if((pressure - gSurface_pressure_bar) <= PRESSURE_HALF_METER)
		return ((float)pBuDiveSettings->gf_high) / 100.0f;

	if(pressure >= gSurface_pressure_bar + gGF_low_depth_bar)
		return ((float)pBuDiveSettings->gf_low) / 100.0f;

	return (pBuDiveSettings->gf_high - gfSteigung * (pressure - gSurface_pressure_bar) )/ 100.0f;
}


void buehlmann_calc_ndl(void)
{
	float local_tissue_nitrogen_bar[16];
	float local_tissue_helium_bar[16];
	int i;

	gNDL = 0;
	//Check ndl always use gHigh
  gGF_value = ((float)pBuDiveSettings->gf_high) / 100.0f;
	//10 minutes steps
	while(gNDL < (300 * 60))
	{
		memcpy(local_tissue_nitrogen_bar, gTissue_nitrogen_bar, (4*16));
		memcpy(local_tissue_helium_bar, gTissue_helium_bar, (4*16));
		//
		gNDL += 600;
    decom_tissues_exposure2(600, &pBuDiveSettings->decogaslist[gGas_id], gPressure,gTissue_nitrogen_bar,gTissue_helium_bar);
		decom_oxygen_calculate_cns_exposure(600,&pBuDiveSettings->decogaslist[gGas_id],gPressure,&gCNS);
		//tissues_exposure_at_gPressure_seconds(600);
		buehlmann_backup_and_restore(true);
		if(dive1_check_deco() == true)
		{
			buehlmann_backup_and_restore(false);
			break;
		}
		buehlmann_backup_and_restore(false);
	}

	if(gNDL < (300 * 60))
		gNDL -= 600;

	if(gNDL > (150 * 60))
		return;

	// refine
	memcpy(gTissue_nitrogen_bar, local_tissue_nitrogen_bar, (4*16));
	memcpy(gTissue_helium_bar, local_tissue_helium_bar, (4*16));

	//One minutes step
	for(i = 0; i < 20; i++)
	{
		gNDL += 60;
		//tissues_exposure_at_gPressure_seconds(60);
		decom_tissues_exposure2(60, &pBuDiveSettings->decogaslist[gGas_id], gPressure,gTissue_nitrogen_bar,gTissue_helium_bar);
		decom_oxygen_calculate_cns_exposure(60,&pBuDiveSettings->decogaslist[gGas_id],gPressure,&gCNS);
		buehlmann_backup_and_restore(true);
		if(dive1_check_deco() == true)
			break;
		buehlmann_backup_and_restore(false);
	}
	//gNDL -= 60;
	return;
}


//  ===============================================================================
//	dive1_check_deco
/// @brief	for NDL calculations
///					160614 using ceilingOther and not ceiling
//  ===============================================================================
_Bool dive1_check_deco(void)
{
	// gGF_value is set in call routine;
	// internes Backup!

	// calc like in deco
	float ceiling;
	float ceilingOther; // new hw 160614

	ceiling = tissue_tolerance();
	ambient_bar_to_deco_stop_depth_bar(ceiling); // this will set gStop.depth :-) (and gStop.id)

	// set the base for all upcoming parameters
	ceilingOther = gStop.depth + gSurface_pressure_bar;

	// modify parameters if there is ascend or parameter fine adjustment
	if(ceilingOther < (gPressure - PRESSURE_150_CM)) // more than 1.5 meter below ceiling
	{
		// ascend within 10 mtr to GF_low // speed 12 mtr/min -> 50 sec / 10 mtr;  15 sec / 3 mtr.
		while(((gPressure - PRESSURE_TEN_METER ) > gSurface_pressure_bar) && (ceiling < (gPressure - PRESSURE_TEN_METER)))
		{
			ascend_with_all_gaschanges(PRESSURE_TEN_METER);
			ceiling = tissue_tolerance();
		}
		while(((gPressure - PRESSURE_THREE_METER )> gSurface_pressure_bar) && (ceiling < gPressure))
		{
			ascend_with_all_gaschanges(PRESSURE_THREE_METER);
			ceiling = tissue_tolerance();
		}
	}
	if(ceiling <= gSurface_pressure_bar)
		return false;
	else
		return true;
}


void buehlmann_ceiling_calculator(SLifeData* pLifeData, SDiveSettings * pDiveSettings, SDecoinfo * pDecoInfo)
{
	float gf_low;
	float gf_high;
	float gf_delta;
	float dv_gf_low_stop_meter;
	_Bool test_result;
	float next_gf_value;
	float next_pressure_absolute;
	float depth_in_meter;
	
	gf_low = pDiveSettings->gf_low;
	gf_high = pDiveSettings->gf_high;

	dv_gf_low_stop_meter = (int)((pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero - pLifeData->pressure_surface_bar) * 10);

	if(dv_gf_low_stop_meter < 1)
	{
		next_gf_value = gf_high; // fix hw 161024
		gf_delta = 0;
	}
	else
	{
		next_gf_value = gf_high;
		gf_delta = gf_high - gf_low;
		gf_delta /= (dv_gf_low_stop_meter * 10); // gf_delta is delta for 10 cm !!
	}

	depth_in_meter = 0;
	next_pressure_absolute = pLifeData->pressure_surface_bar;

	memcpy(gTissue_nitrogen_bar, pLifeData->tissue_nitrogen_bar, (4*16));
	memcpy(gTissue_helium_bar, pLifeData->tissue_helium_bar, (4*16));
	gGF_value = next_gf_value / 100.0f;
	//
	test_result = buehlmann_tissue_test_tolerance(next_pressure_absolute);
	//
	while(!test_result && depth_in_meter < 200)
	{
		depth_in_meter += 0.1;
		next_gf_value = fmaxf(gf_low, next_gf_value - gf_delta);
		gGF_value = next_gf_value / 100.0f;
		next_pressure_absolute += 0.01f; // 0.1 meter down
		test_result = buehlmann_tissue_test_tolerance(next_pressure_absolute);
	}

	if(test_result)
	{
		pDecoInfo->output_ceiling_meter = depth_in_meter;

		if(depth_in_meter >= 0)
		{
			for(int i = 0; i < 10; i++)
			{
				next_gf_value += gf_delta/10.0f;
				gGF_value = next_gf_value / 100.0f;
				next_pressure_absolute -= 0.01f; // 0.1 meter up
				if(!buehlmann_tissue_test_tolerance(next_pressure_absolute))
				{
					pDecoInfo->output_ceiling_meter -= ((float)i)/10.0f;
					break;
				}
			}
		}
	}
	else
	{
		pDecoInfo->output_ceiling_meter = 999;
	}
}


void buehlmann_relative_gradient_calculator(SLifeData* pLifeData, SDiveSettings * pDiveSettings, SDecoinfo * pDecoInfo)
{
	float gf_low;
	float gf_high;
	float gf_delta;
	int dv_gf_low_stop_meter;

	float rgf; // relative gradient factor by hwOS p2_deco.c
	float temp_tissue;
	float limit;
	float pres_respiration;
	float gf;

	gf_low = pDiveSettings->gf_low;
	gf_high = pDiveSettings->gf_high;

	dv_gf_low_stop_meter = (int)((pDiveSettings->internal__pressure_first_stop_ambient_bar_as_upper_limit_for_gf_low_otherwise_zero - pLifeData->pressure_surface_bar) * 10);

	if(dv_gf_low_stop_meter < 1)
	{
		gf_delta = 0;
	}
	else
	{
		gf_delta = gf_high - gf_low;
		gf_delta /= dv_gf_low_stop_meter; // gf_delta is delta for each meter now!!
	}

	
	limit = tissue_tolerance_without_gf_correction(&temp_tissue);
	pres_respiration = pLifeData->pressure_ambient_bar;
	
	if( temp_tissue <= pres_respiration )
	{
		gf = 0.0;
	}
	else
	{
		gf = (temp_tissue  - pres_respiration)
			 / (temp_tissue  - limit)
			 * 100.0f;
	}
	
	if(dv_gf_low_stop_meter < 1)
	{
		rgf = gf_high;
	}
	else
	{
		float temp1 = dv_gf_low_stop_meter; 
		float temp2 = pLifeData->depth_meter;

		if (temp2 <= 0)
				rgf = gf_high;
		else if (temp2 >= temp1)
				rgf = gf_low;
		else
				rgf = gf_low + (temp1 - temp2)*gf_delta;
	}
	
	rgf = gf / rgf;
	
	// avoid discussions about values > 100 below next deco stop
	if((rgf > 1.0f) && (pLifeData->depth_meter >= pDecoInfo->output_ceiling_meter))
		rgf = 1.0f;
	
	pDecoInfo->output_relative_gradient = rgf;
}