summaryrefslogtreecommitdiffstats
path: root/deco.c
AgeCommit message (Collapse)Author
2015-07-07Include units in VPM config structure definitionGravatar Rick Walsh
Include units in the comments of VPM structure definition. We should confirm the units surface_tension_gamma and skin_compression_gammaC. Signed-off-by: Rick Walsh <rickmwalsh@gmail.com> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2015-07-07Use common VPM configuration parametersGravatar Rick Walsh
Adopt the same critical radii used by Eric Baker's original VPM Fortran code and V-Planner. Standard critical volume lambda = 7500 fsw-min (numerous sources). We need to convert it properly. λ = 7500 fsw-min = 7500/33 = 227.2727 ata-min = 227.2727 * 1.01325 bar-min = 230.284 bar-min Signed-off-by: Rick Walsh <rickmwalsh@gmail.com> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2015-07-03VPM-B: add next gradient calculation.Gravatar Jan Darowski
It improves (increases) gradients for all the compartments, so more free gas can be created in the divers body. Next gradients will converge, so the volume won't exceed the safe limit, indicated by the crit_volume_lambda parameter. Function takes time of the last deco in seconds. Requires vpmb_start_gradient() to be run before. Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: add vpm-b based deco checking.Gravatar Jan Darowski
Check during the trial_ascent() if existing pressure gradient is smaller than previously calculated max gradient. If not, ascent is impossible from the vpm-b's point of view. Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: add initial gradient calculation.Gravatar Jan Darowski
Calculate the max difference between tissue saturation and ambient pressure that can be accepted during the ascent. Partial results are kept for later improving in next CVA iterations Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: add nuclei size calculation and nuclear regeneration.Gravatar Jan Darowski
This function calculates the size of nuclei at the end of deco, then simulates their regeneration, to the moment before the deco. This is redundant as nuclear regeneration is a very slow process. Function should be called with time in seconds, just before the ascent. Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: use an analytic solution for nucleon inner pressure instead of binary ↵Gravatar Robert C. Helling
root search According to mathematica In[4]:= f[x_] := x^3 - b x^2 - c In[18]:= Solve[f[x] == 0, x] Out[18]= {{x -> 1/3 (b + ( 2^(1/3) b^2)/(2 b^3 + 27 c + 3 Sqrt[3] Sqrt[4 b^3 c + 27 c^2])^( 1/3) + (2 b^3 + 27 c + 3 Sqrt[3] Sqrt[4 b^3 c + 27 c^2])^(1/3)/ 2^(1/3))}, {x -> b/3 - ((1 + I Sqrt[3]) b^2)/( 3 2^(2/3) (2 b^3 + 27 c + 3 Sqrt[3] Sqrt[4 b^3 c + 27 c^2])^( 1/3)) - ((1 - I Sqrt[3]) (2 b^3 + 27 c + 3 Sqrt[3] Sqrt[4 b^3 c + 27 c^2])^(1/3))/(6 2^(1/3))}, {x -> b/3 - ((1 - I Sqrt[3]) b^2)/( 3 2^(2/3) (2 b^3 + 27 c + 3 Sqrt[3] Sqrt[4 b^3 c + 27 c^2])^( 1/3)) - ((1 + I Sqrt[3]) (2 b^3 + 27 c + 3 Sqrt[3] Sqrt[4 b^3 c + 27 c^2])^(1/3))/(6 2^(1/3))}} For the values of b and c encounterd in the algorithm, the first solution is in fact the only real one that we are after. So we can use this solution instead of doing a binary search for the root of the cubic. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: add initial values for crushing pressure variables.Gravatar Jan Darowski
Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: add crushin pressure calculation.Gravatar Jan Darowski
Add new structures holding vpm-b state. Add function calculating current crushing pressure. Call it from add_segment() on every ambient pressure change. It determines what pressure acts on nuclei during the descent and thus their size at the beggining of the deco. Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: add calculating nucleons inner pressure.Gravatar Jan Darowski
This function calculates the pressure inside the nucleon during the impermeable phase. In the original code, Newton's method is used, for simplicity, we use binary search for finding cubic equations root. Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-07-03VPM-B: add basic algorithm settings.Gravatar Jan Darowski
Created vpmb_config structure based on buehlmann_config. Set it's default values to ones taken from the existing C implementation. Signed-off-by: Jan Darowski <jan.darowski@gmail.com>
2015-01-20Use SAC from preferences for PSCR oxygen dropGravatar Robert C. Helling
The ratio between SAC and oxygen metabolism rate can be assumed constant but not the metabolism rate. So we better base our calculation on the ratio that uses the SAC from the preferences as that pairs well with the O2 consumption from the preferences. Hence we ran remove the sac parameter from fill_pressures(). Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2015-01-17Use correct divemode (PSCR in particular) in deco calculationGravatar Robert C. Helling
I had forgotten this dead code. Sorry. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-11-04Prepare for PSCR calculationsGravatar Robert C. Helling
Calculations for passive semi-closed rebreathers are pretty much like OC except the pO2 is lower bey a certain (SAC dependent) factor. This patch introduces the corresponding calculations in case dctype == PSCR which is so far never set and there is currently no UI for these calculations. As pO2 is SAC dependent it takes a certain attempt at getting it and drops to defaults from the prefs otherwise. As there is no UI at this point and I also don't have any dives, this has not received much testing, yet, but it compiles. At least. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-10-27deco.c: remove unused variables in add_segment()Gravatar Lubomir I. Ivanov
Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-10-26Take water vapor pressure into account again for decoGravatar Robert C. Helling
In the transition to the partial pressure helper function, the water vapor component of the breathing gas had been dropped. This had a significant effect on deco times for deep dives. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-10-13CCR patch: Reorganise the oxygen partial pressure calculationsGravatar willem ferguson
This patch responds to the side effects that the CCR code has had with respect to ceilings in OC dives and dive plans. Dive ceilings are now calculated correctly again. The following were performed: 1) remove the oxygen sensor and setpoint fields from the gas_pressures structure. 2) Re-insert setpoint and oxygen sensor fields in the plot_data structure. 3) Remove the algorithm that reads the o2 sensor data and calculates the pressures.po2 value from function fill_pressures() in dive.c and save it as a separate function calc_ccr_po2() in profile.c. 4) Activate calc_ccr_po2 from function fill_pressures() in profile.c. 5) Move the relative position of the call to fill_pressures() within the function create_polt_info_new() in profile.c. Signed-off-by: willem ferguson <willemferguson@zoology.up.ac.za> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-10-12CCR patch: Oxygen partial pressuresGravatar willem ferguson
This patch does three things: 1) A new function fill_o2_values() is added to profile.c. This fills all oxygen sesnsor and setpoint values that have been zeroed before in order to save space in the dive log. This recreates the full set of sensor values obtained from the original CCR xml log file. 2) Function fill_o2_values() is activated in function create_ plot_info_new() in profile.c 3) The calling parameters to function fill_pressures() in dive.c are changed. The last parameter is now a pointer to a structure of divecomputer. This will be needed in the last patch of the present series of three patches. [Dirk Hohndel: minor whitespace cleanup] Signed-off-by: willem ferguson <willemferguson@zoology.up.ac.za> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-09-19Tissue saturation plot a la Sherwater PretelGravatar Robert C. Helling
This adds a toolbox icon to turn on a tissue plot inspired by the bar graph of the Sherwater Petrel, It shows the inert gas partial pressures for individual compartments. If they are below the ambient pressure (grey line) they are shown in units of the ambient pressure, if they are above, the excess is shown as a percentage of the allowed overpressure for plain Buehlmann. So it has the same units as a gradient factor. Thus also the a gradient factor line (for the current depth) is shown. The different tissues get different colors, greener for the faster ones and bluer for the slower ones. Positioning and on/off icon action still need some tender loving care. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-09-18Helper function for partial pressure calculationGravatar Robert C. Helling
This patch introduces a new structure holding partial pressures (doubles in bar) for all three gases and a helper function to compute them from gasmix (which holds fractions) and ambient pressure. Currentlty this works for OC and CCR, to be extended later to PSCR. Currently the dive_comp_type argument is unused. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-06-25Deco artefacts with low GFlowGravatar Robert C. Helling
In a dive, when you choose a very low GFlow (like 5 or 9) and a trimix with quite some He (12/48 in the example) and descend fast, the ceiling seems to do strange things in the first minutes of the dive (very very deep for example or jumping around). To understand what is going on we have to recall what gradient factors do in detail: Plain Buehlmann gives you for each tissue a maximal inert gas pressure that is a straight line when plotted against the ambient pressure. So for each depth (=ambient pressure) there is a maximally allowed over-pressure. The idea of gradient factors is that one does not use all the possible over-pressure that Buehlmann gives us but only a depth dependent fraction. GFhigh is the fraction of the possible over-pressure at the surface while GFlow is the fraction at the first deco stop. In between, the fraction is linearly interpolated. As the Buehlmann over-pressure is increasing with depth and typically also the allowed overpressure after applications of gradient factors increases with depth or said differently: the tissue saturation has to be lower if the diver wants to ascent. The main problem is: What is the first stop (where to apply GFlow)? In a planned dive, we could take the first deco stop, but in a real dive from a dive computer download it is impossible to say what constitutes a stop and what is only a slow ascent? What I have used so far is not exactly the first stop but rather the first theoretical stop: During all of the dive, I have calculated the ceiling under the assumption that GFlow applies everywhere (and not just at a single depth). The deepest of these ceilings I have used as the “first stop depth”, the depth at which GFlow applies. Even more, I only wanted to use the information that a diver has during the dive, so I actually only considered the ceilings in the past (and not in the future of a given sample). But this brings with it the problem that early in the dive, in particular during the descent the lowest ceiling so far is very shallow (as not much gas has built up in the body so far). This problem now interferes with a second one: If at the start of the dive when the all compartments have 790mbar N2 the diver starts breathing a He-heavy mix (like 12/48) and descents fast the He builds up in the tissues before the N2 can diffuse out. So right at the start, we already encounter high tissue loadings. If now we have a large difference between GFhigh and GFlow but they apply at very similar depth (the surface and a very shallow depth of the deepest ceiling (which for a non-decompression dive would be theoretically at negative depth) so far) it can happen that the linear interpolation as opposite slope then in the typical case above: The allowed over-pressure is degreasing with depth, shallower depth do not require lower gas loading in the tissue (i.e. can be reached after further off-gasing) but but tolerate higher loadings. In that situation the ceiling disappears (or is rather a floor). So far, I got rid of that problem, by stating that the minimum depth for GFlow was 20m (after all, GFlow is about deep stops, so it should better not be too shallow). Now the dive reported in ticket #549 takes values to an extreme in such away that 20m (which is determined by buehlmann_config.gf_low_position_min in deco.c) was not enough to prevent this inversion problem (or in a milder form that the interpolation of gradient factors is in fact an extrapolation with quite extreme values). This patch that gets rid of the problem for the dive described above but still it is possible to find (more extreme) parameter choices that lead to non-realistic ceilings. Let me close by pointing out that all this is only about the descent, as it is about too shallow depth for GFlow. So no real deco (i.e. later part of the dive) is inflicted. This is only about a theoretical ceiling displayed possibly in the first minutes of a dive. So this is more an aesthetically than a practical problem. Fixes #549 Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-06-23Be more consistent in partial pressure namingGravatar Henrik Brautaset Aronsen
Lets just use pO₂ instead of PO2, ppO2, ppO₂, PO₂. They all mean the same, but it's better to be consistent Signed-off-by: Henrik Brautaset Aronsen <subsurface@henrik.synth.no> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-02-27Massive automated whitespace cleanupGravatar Dirk Hohndel
I know everyone will hate it. Go ahead. Complain. Call me names. At least now things are consistent and reproducible. If you want changes, have your complaint come with a patch to scripts/whitespace.pl so that we can automate it. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-01-19Stop doing the (very expensive) pow() calculation pointlesslyGravatar Linus Torvalds
This re-organizes the saturation calculations to be in my opinion clearer: we used to have the "one second" case completely separate from the "generic interval" case, and this undoes that. It *does* keep the special static cache for the one-second buehlmann factors, and expands that with a *dynamic* cache for each tissue index that contains the previous value of the buehlmann factor for a particular duration. The point is, usually we end up using some fixed duration, so the cache hit ratio is quite high. And doing a memory load from a cache is *much* faster than calculating exponentials. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2014-01-16Convert the C code to using stdbool and true/falseGravatar Anton Lundin
Earlier we converted the C++ code to using true/false, and this converts the C code to using the same style. We already depended on stdbool.h in subsurfacestartup.[ch], and we build with -std=gnu99 so nobody could build subsurface without a c99 compiler. [Dirk Hohndel: small change suggested by Thiago Macieira: don't include stdbool.h for C++] Signed-off-by: Anton Lundin <glance@acc.umu.se> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-12-20Add preprocessor directives around debug functionsGravatar Anton Lundin
These adds some ifdef's around some debug functions to disable them when not using them. Signed-off-by: Anton Lundin <glance@acc.umu.se> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-11-21Added a configuration option to have gf_low apply at max depth instead of at ↵Gravatar Patrick Valsecchi
deepest ceiling. Signed-off-by: Patrick Valsecchi <patrick@thus.ch> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-10-07Fix some signedness issuesGravatar Dirk Hohndel
I always worry if these are worth following up on - but these seem pretty clear and obvious to me. As far as the planner is concerned, depth is unsigned. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-10-06First steps towards removing glib dependenciesGravatar Dirk Hohndel
- remove the build flags and libraries from the Makefile / Configure.mk - remove the glib types (gboolean, gchar, gint64, gint) - comment out / hack around gettext - replace the glib file helper functions - replace g_ascii_strtod - replace g_build_filename - use environment variables instead of g_get_home_dir() & g_get_user_name() - comment out GPS string parsing (uses glib utf8 macros) This needs massive cleanup, but it's a snapshot of what I have right now, in case people want to look at it. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-05-31Show ceilings for individual tissuesGravatar Robert Helling
I think that displaying tissue loadings either as pressure or as percentages is not very intuitive but that it makes much more sense when translated to ceiling depths. This change enables just that for the 16 tissues in our calculated ceiling and visualizes this in the profile graph. There is a checkbox in the preferences to turn this on. If enabled, all tissues having non-trivial ceilings are also shown in the info box. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-05-29Connect preferences to the rest of the codeGravatar Dirk Hohndel
The biggest problem here was that bool has different sizes in C and C++ code. So using this in a structure shared between the two sides wasn't a smart idea. Instead I went with 'short', but that caused problems with Qt being to smart for its own good and not doing the right thing when dealing with 'boolean' settings and a short value. This may be something in the way I implemented things (as I doubt that something this fundamental would be broken) but the workaround implemented here (explicitly using 0 or 1 depending on the value of the boolean) seems to work. I also decided to get rid of the confusion of where gflow/gfhigh are floating point (0..1) and when they are integers (0..100). We now use integers anywhere outside of deco.c. I also applied some serious spelling corrections to the preferences dialog's ui file. Finally, this enables the code that selects which partial pressure graph to show. Still to do: font size, metric/imperial logic Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-03-28Use the new get_o2()/get_he() helper functions more widelyGravatar Linus Torvalds
They do the "02=0 means air" thing autmatically, and make for less typing. So use them more widely in places that looked up the o2 and he permille values of a gasmix. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-02-09Clean up the handling of surface pressureGravatar Dirk Hohndel
There are two ways to look at surface pressure. One is to say "what was the surface pressure during that dive?" - in that case we now return an average over the pressure reported by the different divecomputers (or the standard 1013mbar if none reported any). Or you want to do specific calculations for a specific divecomputer - in which case we access only the pressure reported by THAT divecomputer, if present (and fall back to the previous case, otherwise). We still have lots of places in Subsurface that only act on the first divecomputer. As a side effect of this change we now make this more obvious as we in those cases pass a pointer to the first divecomputer explicitly to the calculations. Either way, this commit should prevent us from ever mistakenly basing our calculations on a surface pressure of 0 (which is the initial bug in deco.c that triggered all this). Similar changes need to be made for other elements that we currently only use from the first divecomputer, i.e., salinity. Reported-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-02-08Remove the tissue_tolerated_ambient_pressure[] arrayGravatar Linus Torvalds
It wasn't really used. The only reader of that array was the same thing that wrote the entry, so instead of storing it in the array (and never using it ever after), just use the calculation directly, and remove the array entirely. This makes it much easier to see that the gradient factors are not used for any long-term state. We use them only for the pressure tolerance calculations at that particular point, and there is no "history" associated with it. This matters mainly because it means that we can do all the deco initialization and setup without worrying about exactly which gradient factors we will use. And we can use different gradient factors for diving and planning and no-fly calculations without the GF choice affecting the tissue state. Acked-by: Robert C. Helling <helling@lmu.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-02-08The 'gasmix' argument to add_segment() is read-onlyGravatar Linus Torvalds
We'll want to use a 'static const' gasmix for the upcoming no-fly-time code, so prepare for it by just marking the read-only gasmix argument as 'const'. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-02-03Fixing SP handling in planner, adding eventGravatar Jan Schubert
This moves some double/floating handling for po2 to plain integer. There are still non int values around (also for phe and po2) in the plot area. Signed-off-by: Jan Schubert <Jan.Schubert@GMX.li> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-30Massive cleanupGravatar Dirk Hohndel
Mostly coding style and whitespace changes plus making lots of functions static that have no need to be extern. This also helped find a bit of code that is actually no longer used. This should have absolutely no functional impact - all changes should be purely cosmetic. But it removes a bunch of lines of code and makes the rest easier to read. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-25Removed unused structure definition in deco.cGravatar Dirk Hohndel
Leftover from the initial implementation. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-23Move more dive computer filled data to the divecomputer structureGravatar Linus Torvalds
This moves the fields 'duration', 'surfacetime', 'maxdepth', 'meandepth', 'airtemp', 'watertemp', 'salinity' and 'surface_pressure' to the per-divecomputer data structure. They are filled in by the dive computer, and normally not edited. NOTE! All actual *use* of this data was then changed from dive->field to dive->dc.field programmatically with a shell-script and sed, and the result then edited for details. So while the XML save and restore code has been updated, all the displaying etc will currently always just show the first dive computer entry. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-14Centralising and redefining values as integersGravatar Jan Schubert
This patch centralizes the definition for surface pressure, oxygen in air, (re)defines all such values as plain integers and adapts calculations. It eliminates 11 (!) occurrences of definitions for surface pressure and also a few for oxygen in air. It also rewrites the calculation for EAD, END and EADD using the new definitons, harmonizing it for OC and CC and fixes a bug for EADD OC calculation. And finally it removes the unneeded variable entry_ead in gtk-gui.c. Jan Signed-off-by: Jan Schubert <Jan.Schubert@GMX.li> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-13Add support for MOD, EAD, AND and EADD in the mouse over displayGravatar Dirk Hohndel
- MOD: Maximum Operation Depth based on a configurable limit - EAD: Equivalent Air Depth considering N2 and (!) O2 narcotic - END: Equivalent Nitrogen (Narcotic) Depth considering just N2 narcotic (ignoring O2) - EADD: Equivalent Air Density Depth Please note that some people and even diving organisations have opposite definitions for EAD and END. Considering A stands for Air, lets choose the above. And considering N for Nitrogen it also fits in this scheme. This patch moves N2_IN_AIR from deco.c to dive.h as this is already used in several places and might be useful for future use also. It also respecifies N2_IN_AIR to a more correct value of 78,084%, the former one also included all other gases than oxygen appearing in air. If someone needs to use the former value it would be more correct to use 1-O2_IN_AIR instead. Signed-off-by: Jan Schubert / Jan.Schubert@GMX.li Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-10Adjust GFlow to apply at deepest ceiling instead of at max depthGravatar Robert C. Helling
This moves the point where GF_low applies up which implies that at all shallower depth (i.e. during deco) a lower GF results which makes the deco longer compared to the previous implementation. Of course, "GF_low" applies at first deco stop is a bit tricky since the depth of the first deco stop again depends on GF_low, i.e. there is another equation to solve. You can do this by inverting the equation for the ambient pressure and use GF_low as the gradient factor. This yields amb = (b * M_value_corrected - GF_low * a * b) / ((1-b) * GF_low + b) Signed-off-by: Robert C. Helling helling@atdotde.de Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-08Undo unintentional change to deco.cGravatar Dirk Hohndel
In commit d163a68ac69e "Clean up the rewritten deco.c" I apparently made one more change than I intended - I changed the last deco stop back to 3m instead of allowing the smooth mode to go all the way back to 0 without any discrete steps. This fixes that mistake. Reported-by: Robert C. Helling <helling@lmu.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-08Minor cleanupsGravatar Dirk Hohndel
Coding style in deco.c. Unneccessary if clause in profile.c (the loop starts with i = 1) Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-08Clean up the rewritten deco.cGravatar Dirk Hohndel
In commit a7902f279a57 "Rewrite of the deco code" Robert kept the old code that he replaced around; I removed all that as it's in the git history if we ever need to look at it again but doesn't really help us in the file as it is. I also removed constants, variables and config parameters that aren't used in the new implementation and did some coding style / formatting changes to make deco.c more consistent with the rest of Subsurface. I also updated the comments at the top of the file to reflect reality. I did one change that actually affects the code. In the explanation of his changes Robert said that gf_low_pressure_this_dive is initialized to the exquivalent of 20m, yet his code added the surface pressure twice. I decided to change the default config value from 3 (bar) to 2 so that this indeed reflects (about) 20m (as in the code below surface_pressure is added to this value). Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-08Rewrite of the deco codeGravatar Robert C. Helling
o) Instead of using gradient factors as means of comparison, I now use pressure (as in: maximal ambient pressure). o) tissue_tolerance_calc() now computes the maximal ambient pressure now respecting gradient factors. For this, it needs to know about the surface pressure (as refernce for GF_high), thus gets *dive as an argument. It is called from add_segment() which this also needs *dive as an additional argument. o) This implies deco_allowed_depth is now mainly a ambient-pressure to depth conversion with decorations to avoid negative depth (i.e. no deco obliation), implementation of quantization (!smooth => multiples of 3m) and explicit setting of last deco depth (e.g. 6m for O2 deco). o) gf_low_pressure_this_dive (slight change of name), the max depth in pressure units is updated in add_segment. I set the minimal value in buehlmann_config to the equivalent of 20m as otherwise good values of GF_low add a lot of deco to shallow dives which do not need deep stops in the first place. o) The bogus loop is gone as well as actual_gradient_limit() and gradient_factor_calculation() and large parts of deco_allowed_depth() although I did not delete the code but put it in comments. o) The meat is in the formula in lines 147-154 of deco.c. Here is the rationale: Without gradient factors, the M-value (i.e the maximal tissue pressure) at a given depth is given by ambient_pressure / buehlmann_b + a. According to "Clearing Up The Confusion About "Deep Stops" by Erik C. Baker (as found via google) the effect of the gradient factors is no replace this by a reduced affine relation (i.e. another line) such that at the surface the difference between M-value and ambient pressure is reduced by a factor GF_high and at the maximal depth by a factor GF_low. That is, we are looking for parameters alpha and beta such that alpha surface + beta = surface + gf_high * (surface/b + a - surface) and alpha max_p + beta = max_p + gf_low * (max_p/b + a - max_p) This can be solved for alpha and beta and then inverted to obtain the max ambient pressure given tissue loadings. The result is the above mentioned formula. Signed-off-by: Robert C. Helling <helling@atdotde.de> Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-07Add bailout code to prevent infinite loop in deco calculationGravatar Dirk Hohndel
This appears to happen if we have impossible dive sequences in the dive_list (i.e., merging XML files from two different divers with overlapping trips). We need to fix the underlying cause for this issue (i.e., only pick the 'right' dives to calculate the residual tissue saturation), but at least this code prevents the hang in an infinite loop. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-06Add the ability to cache our deco stateGravatar Dirk Hohndel
We kept reduing all the deco calculations, including the previous dives (if any) for each segment we add to the dive plan. This simply remembers the last stage and then just adds to that. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-05Fix bug in smooth ceiling modeGravatar Dirk Hohndel
The ceiling calculations for the gradient factors still had a 3m increment hardcoded. This is now also conditional on the smooth parameter. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
2013-01-04Correctly handle air in the deco codeGravatar Dirk Hohndel
We mark air with o2.permille = 0. But it's actually 20.9% O2. Signed-off-by: Dirk Hohndel <dirk@hohndel.org>