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view Discovery/Inc/vpm.h @ 224:ceecabfddb57 div-fixes-3
Bugfix, deco: fix 2 (small) problems with calculated ceiling
This fixes 1 trivial, and 1 not really trivial bug in the calculation
of the ceiling. When simulating a bounce dive to 80m, things become
clear (tried this on a CCR dive, fixed setpoint 1.2bar, about 15 minutes
of bottom time). Closely watch the behavior of the ceiling data. At some
point during the ascent, the ceiling begins to decrease in 10cm steps.
Then suddenly (while still ascending), the ceiling increases again with 1m,
does not change for some time, and then suddenly steps 1.1m less deep.
While not very relevant to real deco diving, it is simply wrong.
The reason for this is subtle. The algorithm used to find the ceiling
is a sort of linear search, stepping down a meter, overshoot the depth, and
search back in 10cm steps. It seems some numerical instability. Fixing
this, was a bit more computational intensive search by stepping up down in
equal steps of 10cm. But, I'm pretty sure that things can be speeded up here, as a
ceiling does not change fast, so it should be not that difficult to limit
the search space, or use a binary search algorithm instead.
The trivial second problem fixed, is that the ceiling ends at the surface
and not at 1m depth. This small issue became visible after changing the step
down size above.
Signed-off-by: Jan Mulder <jlmulder@xs4all.nl>
author | Jan Mulder <jlmulder@xs4all.nl> |
---|---|
date | Sun, 31 Mar 2019 19:35:51 +0200 |
parents | 5f11787b4f42 |
children | 5e0bb91d4a12 |
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/////////////////////////////////////////////////////////////////////////////// /// -*- coding: UTF-8 -*- /// /// \file Discovery/Inc/vpm.h /// \brief Varying Permeability Model (VPM) Decompression Program /// \author Heinrichs Weikamp /// \date 23.04.2013 /// /// $Id$ /////////////////////////////////////////////////////////////////////////////// /// \par Copyright (c) 2014-2018 Heinrichs Weikamp gmbh /// /// This program is free software: you can redistribute it and/or modify /// it under the terms of the GNU General Public License as published by /// the Free Software Foundation, either version 3 of the License, or /// (at your option) any later version. /// /// This program is distributed in the hope that it will be useful, /// but WITHOUT ANY WARRANTY; without even the implied warranty of /// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the /// GNU General Public License for more details. /// /// You should have received a copy of the GNU General Public License /// along with this program. If not, see <http://www.gnu.org/licenses/>. ////////////////////////////////////////////////////////////////////////////// #ifndef VPM_H #define VPM_H #include "buehlmann.h" #include "data_central.h" extern long vpm_time_calc_begin; enum DECOLIST{DECOSTOPS,FUTURESTOPS,BAILOUTSTOPS, OFF = -1}; // order is important!! enum VPM_CALC_STATUS{CALC_END, CALC_BEGIN, CALC_CRITICAL, CALC_FINAL_DECO, CALC_NULLZEIT }; //int calc_crushing_pressure(float *starting_depth, float *ending_depth, float *rate); //void vpm_check_calc(unsigned short* stoplist); //void vpm_init(void); //_Bool vpm_crush(void); //void vpm_reset_variables(void); //_Bool vpm_build_variables_from_file(unsigned long in_sdram_start); //int vpm_store_variables_in_sdram_for_transfer(unsigned long in_sdram_start); //void vpm_calc_crushing_pressure(float starting_ambient_pressure, float ending_ambient_pressure, float rate); //void vpm_deco_plan(unsigned short divetime,unsigned short * divetime_first_stop, float* first_stop_depth); float schreiner_equation__2(float *initial_inspired_gas_pressure,float *rate_change_insp_gas_pressure,float *interval_time_minutes, const float *gas_time_constant,float *initial_gas_pressure); int vpm_calc(SLifeData* pINPUT, SDiveSettings* diveSettings, SVpm* pVPM, SDecoinfo* pDECOINFO, int calc_what); void vpm_saturation_after_ascent(SLifeData* input); extern const float helium_time_constant[16]; extern const float nitrogen_time_constant[16]; float vpm_get_CNS(void); #endif /* VPM_H */