xref: /petsc/src/ts/tests/ex5.c (revision a336c15037c72f93cd561f5a5e11e93175f2efd9)
1 static char help[] = "Nonlinear, time-dependent. Developed from radiative_surface_balance.c \n";
2 /*
3   Contributed by Steve Froehlich, Illinois Institute of Technology
4 
5    Usage:
6     mpiexec -n <np> ./ex5 [options]
7     ./ex5 -help  [view PETSc options]
8     ./ex5 -ts_type sundials -ts_view
9     ./ex5 -da_grid_x 20 -da_grid_y 20 -log_view
10     ./ex5 -da_grid_x 20 -da_grid_y 20 -ts_type rosw -ts_atol 1.e-6 -ts_rtol 1.e-6
11     ./ex5 -drawcontours -draw_pause 0.1 -draw_fields 0,1,2,3,4
12 */
13 
14 /*
15    -----------------------------------------------------------------------
16 
17    Governing equations:
18 
19         R      = s*(Ea*Ta^4 - Es*Ts^4)
20         SH     = p*Cp*Ch*wind*(Ta - Ts)
21         LH     = p*L*Ch*wind*B(q(Ta) - q(Ts))
22         G      = k*(Tgnd - Ts)/dz
23 
24         Fnet   = R + SH + LH + G
25 
26         du/dt  = -u*(du/dx) - v*(du/dy) - 2*omeg*sin(lat)*v - (1/p)*(dP/dx)
27         dv/dt  = -u*(dv/dx) - v*(dv/dy) + 2*omeg*sin(lat)*u - (1/p)*(dP/dy)
28         dTs/dt = Fnet/(Cp*dz) - Div([u*Ts, v*Ts]) + D*Lap(Ts)
29                = Fnet/(Cs*dz) - u*(dTs/dx) - v*(dTs/dy) + D*(Ts_xx + Ts_yy)
30         dp/dt  = -Div([u*p,v*p])
31                = - u*dp/dx - v*dp/dy
32         dTa/dt = Fnet/Cp
33 
34    Equation of State:
35 
36         P = p*R*Ts
37 
38    -----------------------------------------------------------------------
39 
40    Program considers the evolution of a two dimensional atmosphere from
41    sunset to sunrise. There are two components:
42                 1. Surface energy balance model to compute diabatic dT (Fnet)
43                 2. Dynamical model using simplified primitive equations
44 
45    Program is to be initiated at sunset and run to sunrise.
46 
47    Inputs are:
48                 Surface temperature
49                 Dew point temperature
50                 Air temperature
51                 Temperature at cloud base (if clouds are present)
52                 Fraction of sky covered by clouds
53                 Wind speed
54                 Precipitable water in centimeters
55                 Wind direction
56 
57    Inputs are read in from the text file ex5_control.txt. To change an
58    input value use ex5_control.txt.
59 
60    Solvers:
61             Backward Euler = default solver
62             Sundials = fastest and most accurate, requires Sundials libraries
63 
64    This model is under development and should be used only as an example
65    and not as a predictive weather model.
66 */
67 
68 #include <petscts.h>
69 #include <petscdm.h>
70 #include <petscdmda.h>
71 
72 /* stefan-boltzmann constant */
73 #define SIG 0.000000056703
74 /* absorption-emission constant for surface */
75 #define EMMSFC 1
76 /* amount of time (seconds) that passes before new flux is calculated */
77 #define TIMESTEP 1
78 
79 /* variables of interest to be solved at each grid point */
80 typedef struct {
81   PetscScalar Ts, Ta; /* surface and air temperature */
82   PetscScalar u, v;   /* wind speed */
83   PetscScalar p;      /* density */
84 } Field;
85 
86 /* User defined variables. Used in solving for variables of interest */
87 typedef struct {
88   DM          da;             /* grid */
89   PetscScalar csoil;          /* heat constant for layer */
90   PetscScalar dzlay;          /* thickness of top soil layer */
91   PetscScalar emma;           /* emission parameter */
92   PetscScalar wind;           /* wind speed */
93   PetscScalar dewtemp;        /* dew point temperature (moisture in air) */
94   PetscScalar pressure1;      /* sea level pressure */
95   PetscScalar airtemp;        /* temperature of air near boundary layer inversion */
96   PetscScalar Ts;             /* temperature at the surface */
97   PetscScalar fract;          /* fraction of sky covered by clouds */
98   PetscScalar Tc;             /* temperature at base of lowest cloud layer */
99   PetscScalar lat;            /* Latitude in degrees */
100   PetscScalar init;           /* initialization scenario */
101   PetscScalar deep_grnd_temp; /* temperature of ground under top soil surface layer */
102 } AppCtx;
103 
104 /* Struct for visualization */
105 typedef struct {
106   PetscBool   drawcontours; /* flag - 1 indicates drawing contours */
107   PetscViewer drawviewer;
108   PetscInt    interval;
109 } MonitorCtx;
110 
111 /* Inputs read in from text file */
112 struct in {
113   PetscScalar Ts;     /* surface temperature  */
114   PetscScalar Td;     /* dewpoint temperature */
115   PetscScalar Tc;     /* temperature of cloud base */
116   PetscScalar fr;     /* fraction of sky covered by clouds */
117   PetscScalar wnd;    /* wind speed */
118   PetscScalar Ta;     /* air temperature */
119   PetscScalar pwt;    /* precipitable water */
120   PetscScalar wndDir; /* wind direction */
121   PetscScalar lat;    /* latitude */
122   PetscReal   time;   /* time in hours */
123   PetscScalar init;
124 };
125 
126 /* functions */
127 extern PetscScalar    emission(PetscScalar);                         /* sets emission/absorption constant depending on water vapor content */
128 extern PetscScalar    calc_q(PetscScalar);                           /* calculates specific humidity */
129 extern PetscScalar    mph2mpers(PetscScalar);                        /* converts miles per hour to meters per second */
130 extern PetscScalar    Lconst(PetscScalar);                           /* calculates latent heat constant taken from Satellite estimates of wind speed and latent heat flux over the global oceans., Bentamy et al. */
131 extern PetscScalar    fahr_to_cel(PetscScalar);                      /* converts Fahrenheit to Celsius */
132 extern PetscScalar    cel_to_fahr(PetscScalar);                      /* converts Celsius to Fahrenheit */
133 extern PetscScalar    calcmixingr(PetscScalar, PetscScalar);         /* calculates mixing ratio */
134 extern PetscScalar    cloud(PetscScalar);                            /* cloud radiative parameterization */
135 extern PetscErrorCode FormInitialSolution(DM, Vec, void *);          /* Specifies initial conditions for the system of equations (PETSc defined function) */
136 extern PetscErrorCode RhsFunc(TS, PetscReal, Vec, Vec, void *);      /* Specifies the user defined functions                     (PETSc defined function) */
137 extern PetscErrorCode Monitor(TS, PetscInt, PetscReal, Vec, void *); /* Specifies output and visualization tools                 (PETSc defined function) */
138 extern PetscErrorCode readinput(struct in *put);                     /* reads input from text file */
139 extern PetscErrorCode calcfluxs(PetscScalar, PetscScalar, PetscScalar, PetscScalar, PetscScalar, PetscScalar *); /* calculates upward IR from surface */
140 extern PetscErrorCode calcfluxa(PetscScalar, PetscScalar, PetscScalar, PetscScalar *);                           /* calculates downward IR from atmosphere */
141 extern PetscErrorCode sensibleflux(PetscScalar, PetscScalar, PetscScalar, PetscScalar *);                        /* calculates sensible heat flux */
142 extern PetscErrorCode potential_temperature(PetscScalar, PetscScalar, PetscScalar, PetscScalar, PetscScalar *);  /* calculates potential temperature */
143 extern PetscErrorCode latentflux(PetscScalar, PetscScalar, PetscScalar, PetscScalar, PetscScalar *);             /* calculates latent heat flux */
144 extern PetscErrorCode calc_gflux(PetscScalar, PetscScalar, PetscScalar *);                                       /* calculates flux between top soil layer and underlying earth */
145 
146 int main(int argc, char **argv)
147 {
148   PetscInt      time; /* amount of loops */
149   struct in     put;
150   PetscScalar   rh;                 /* relative humidity */
151   PetscScalar   x;                  /* memory variable for relative humidity calculation */
152   PetscScalar   deep_grnd_temp;     /* temperature of ground under top soil surface layer */
153   PetscScalar   emma;               /* absorption-emission constant for air */
154   PetscScalar   pressure1 = 101300; /* surface pressure */
155   PetscScalar   mixratio;           /* mixing ratio */
156   PetscScalar   airtemp;            /* temperature of air near boundary layer inversion */
157   PetscScalar   dewtemp;            /* dew point temperature */
158   PetscScalar   sfctemp;            /* temperature at surface */
159   PetscScalar   pwat;               /* total column precipitable water */
160   PetscScalar   cloudTemp;          /* temperature at base of cloud */
161   AppCtx        user;               /*  user-defined work context */
162   MonitorCtx    usermonitor;        /* user-defined monitor context */
163   TS            ts;
164   SNES          snes;
165   DM            da;
166   Vec           T, rhs; /* solution vector */
167   Mat           J;      /* Jacobian matrix */
168   PetscReal     ftime, dt;
169   PetscInt      steps, dof = 5;
170   PetscBool     use_coloring  = PETSC_TRUE;
171   MatFDColoring matfdcoloring = 0;
172   PetscBool     monitor_off   = PETSC_FALSE;
173   PetscBool     prunejacobian = PETSC_FALSE;
174 
175   PetscFunctionBeginUser;
176   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
177 
178   /* Inputs */
179   PetscCall(readinput(&put));
180 
181   sfctemp   = put.Ts;
182   dewtemp   = put.Td;
183   cloudTemp = put.Tc;
184   airtemp   = put.Ta;
185   pwat      = put.pwt;
186 
187   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Initial Temperature = %g\n", (double)sfctemp)); /* input surface temperature */
188 
189   deep_grnd_temp = sfctemp - 10;   /* set underlying ground layer temperature */
190   emma           = emission(pwat); /* accounts for radiative effects of water vapor */
191 
192   /* Converts from Fahrenheit to Celsius */
193   sfctemp        = fahr_to_cel(sfctemp);
194   airtemp        = fahr_to_cel(airtemp);
195   dewtemp        = fahr_to_cel(dewtemp);
196   cloudTemp      = fahr_to_cel(cloudTemp);
197   deep_grnd_temp = fahr_to_cel(deep_grnd_temp);
198 
199   /* Converts from Celsius to Kelvin */
200   sfctemp += 273;
201   airtemp += 273;
202   dewtemp += 273;
203   cloudTemp += 273;
204   deep_grnd_temp += 273;
205 
206   /* Calculates initial relative humidity */
207   x        = calcmixingr(dewtemp, pressure1);
208   mixratio = calcmixingr(sfctemp, pressure1);
209   rh       = (x / mixratio) * 100;
210 
211   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Initial RH = %.1f percent\n\n", (double)rh)); /* prints initial relative humidity */
212 
213   time = 3600 * put.time; /* sets amount of timesteps to run model */
214 
215   /* Configure PETSc TS solver */
216   /*------------------------------------------*/
217 
218   /* Create grid */
219   PetscCall(DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_PERIODIC, DM_BOUNDARY_PERIODIC, DMDA_STENCIL_STAR, 20, 20, PETSC_DECIDE, PETSC_DECIDE, dof, 1, NULL, NULL, &da));
220   PetscCall(DMSetFromOptions(da));
221   PetscCall(DMSetUp(da));
222   PetscCall(DMDASetUniformCoordinates(da, 0.0, 1.0, 0.0, 1.0, 0.0, 1.0));
223 
224   /* Define output window for each variable of interest */
225   PetscCall(DMDASetFieldName(da, 0, "Ts"));
226   PetscCall(DMDASetFieldName(da, 1, "Ta"));
227   PetscCall(DMDASetFieldName(da, 2, "u"));
228   PetscCall(DMDASetFieldName(da, 3, "v"));
229   PetscCall(DMDASetFieldName(da, 4, "p"));
230 
231   /* set values for appctx */
232   user.da             = da;
233   user.Ts             = sfctemp;
234   user.fract          = put.fr;         /* fraction of sky covered by clouds */
235   user.dewtemp        = dewtemp;        /* dew point temperature (mositure in air) */
236   user.csoil          = 2000000;        /* heat constant for layer */
237   user.dzlay          = 0.08;           /* thickness of top soil layer */
238   user.emma           = emma;           /* emission parameter */
239   user.wind           = put.wnd;        /* wind speed */
240   user.pressure1      = pressure1;      /* sea level pressure */
241   user.airtemp        = airtemp;        /* temperature of air near boundar layer inversion */
242   user.Tc             = cloudTemp;      /* temperature at base of lowest cloud layer */
243   user.init           = put.init;       /* user chosen initiation scenario */
244   user.lat            = 70 * 0.0174532; /* converts latitude degrees to latitude in radians */
245   user.deep_grnd_temp = deep_grnd_temp; /* temp in lowest ground layer */
246 
247   /* set values for MonitorCtx */
248   usermonitor.drawcontours = PETSC_FALSE;
249   PetscCall(PetscOptionsHasName(NULL, NULL, "-drawcontours", &usermonitor.drawcontours));
250   if (usermonitor.drawcontours) {
251     PetscReal bounds[] = {1000.0, -1000., -1000., -1000., 1000., -1000., 1000., -1000., 1000, -1000, 100700, 100800};
252     PetscCall(PetscViewerDrawOpen(PETSC_COMM_WORLD, 0, 0, 0, 0, 300, 300, &usermonitor.drawviewer));
253     PetscCall(PetscViewerDrawSetBounds(usermonitor.drawviewer, dof, bounds));
254   }
255   usermonitor.interval = 1;
256   PetscCall(PetscOptionsGetInt(NULL, NULL, "-monitor_interval", &usermonitor.interval, NULL));
257 
258   /*  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
259      Extract global vectors from DA;
260    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
261   PetscCall(DMCreateGlobalVector(da, &T));
262   PetscCall(VecDuplicate(T, &rhs)); /* r: vector to put the computed right-hand side */
263 
264   PetscCall(TSCreate(PETSC_COMM_WORLD, &ts));
265   PetscCall(TSSetProblemType(ts, TS_NONLINEAR));
266   PetscCall(TSSetType(ts, TSBEULER));
267   PetscCall(TSSetRHSFunction(ts, rhs, RhsFunc, &user));
268 
269   /* Set Jacobian evaluation routine - use coloring to compute finite difference Jacobian efficiently */
270   PetscCall(DMSetMatType(da, MATAIJ));
271   PetscCall(DMCreateMatrix(da, &J));
272   if (use_coloring) {
273     ISColoring iscoloring;
274     PetscInt   ncolors;
275 
276     PetscCall(DMCreateColoring(da, IS_COLORING_GLOBAL, &iscoloring));
277     PetscCall(MatFDColoringCreate(J, iscoloring, &matfdcoloring));
278     PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
279     PetscCall(MatFDColoringSetUp(J, iscoloring, matfdcoloring));
280     PetscCall(ISColoringGetColors(iscoloring, NULL, &ncolors, NULL));
281     PetscCall(PetscPrintf(PETSC_COMM_WORLD, "DMColoring generates %" PetscInt_FMT " colors\n", ncolors));
282     PetscCall(ISColoringDestroy(&iscoloring));
283     PetscCall(TSSetIJacobian(ts, J, J, TSComputeIJacobianDefaultColor, NULL));
284   } else {
285     PetscCall(TSGetSNES(ts, &snes));
286     PetscCall(SNESSetJacobian(snes, J, J, SNESComputeJacobianDefault, NULL));
287   }
288 
289   /* Define what to print for ts_monitor option */
290   PetscCall(PetscOptionsHasName(NULL, NULL, "-monitor_off", &monitor_off));
291   if (!monitor_off) PetscCall(TSMonitorSet(ts, Monitor, &usermonitor, NULL));
292   dt    = TIMESTEP; /* initial time step */
293   ftime = TIMESTEP * time;
294   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "time %" PetscInt_FMT ", ftime %g hour, TIMESTEP %g\n", time, (double)(ftime / 3600), (double)dt));
295 
296   PetscCall(TSSetTimeStep(ts, dt));
297   PetscCall(TSSetMaxSteps(ts, time));
298   PetscCall(TSSetMaxTime(ts, ftime));
299   PetscCall(TSSetExactFinalTime(ts, TS_EXACTFINALTIME_STEPOVER));
300   PetscCall(TSSetSolution(ts, T));
301   PetscCall(TSSetDM(ts, da));
302 
303   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
304      Set runtime options
305    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
306   PetscCall(PetscOptionsGetBool(NULL, NULL, "-prune_jacobian", &prunejacobian, NULL));
307   PetscCall(TSSetFromOptions(ts));
308   if (prunejacobian && matfdcoloring) {
309     PetscRandom rctx;
310     Vec         Tdot;
311     /* Compute the Jacobian with randomized vector values to capture the sparsity pattern for coloring */
312     PetscCall(VecDuplicate(T, &Tdot));
313     PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rctx));
314     PetscCall(PetscRandomSetInterval(rctx, 1.0, 2.0));
315     PetscCall(VecSetRandom(T, rctx));
316     PetscCall(VecSetRandom(Tdot, rctx));
317     PetscCall(PetscRandomDestroy(&rctx));
318     PetscCall(TSSetUp(ts));
319     PetscCall(TSComputeIJacobian(ts, 0.0, T, Tdot, 0.12345, J, J, PETSC_FALSE));
320     PetscCall(VecDestroy(&Tdot));
321     PetscCall(MatFDColoringDestroy(&matfdcoloring));
322     PetscCall(TSPruneIJacobianColor(ts, J, J));
323   }
324   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
325      Solve nonlinear system
326      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
327   PetscCall(FormInitialSolution(da, T, &user));
328   PetscCall(TSSolve(ts, T));
329   PetscCall(TSGetSolveTime(ts, &ftime));
330   PetscCall(TSGetStepNumber(ts, &steps));
331   PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Solution T after %g hours %" PetscInt_FMT " steps\n", (double)(ftime / 3600), steps));
332 
333   if (matfdcoloring) PetscCall(MatFDColoringDestroy(&matfdcoloring));
334   if (usermonitor.drawcontours) PetscCall(PetscViewerDestroy(&usermonitor.drawviewer));
335   PetscCall(MatDestroy(&J));
336   PetscCall(VecDestroy(&T));
337   PetscCall(VecDestroy(&rhs));
338   PetscCall(TSDestroy(&ts));
339   PetscCall(DMDestroy(&da));
340 
341   PetscCall(PetscFinalize());
342   return 0;
343 }
344 /*****************************end main program********************************/
345 /*****************************************************************************/
346 /*****************************************************************************/
347 /*****************************************************************************/
348 PetscErrorCode calcfluxs(PetscScalar sfctemp, PetscScalar airtemp, PetscScalar emma, PetscScalar fract, PetscScalar cloudTemp, PetscScalar *flux)
349 {
350   PetscFunctionBeginUser;
351   *flux = SIG * ((EMMSFC * emma * PetscPowScalarInt(airtemp, 4)) + (EMMSFC * fract * (1 - emma) * PetscPowScalarInt(cloudTemp, 4)) - (EMMSFC * PetscPowScalarInt(sfctemp, 4))); /* calculates flux using Stefan-Boltzmann relation */
352   PetscFunctionReturn(PETSC_SUCCESS);
353 }
354 
355 PetscErrorCode calcfluxa(PetscScalar sfctemp, PetscScalar airtemp, PetscScalar emma, PetscScalar *flux) /* this function is not currently called upon */
356 {
357   PetscScalar emm = 0.001;
358 
359   PetscFunctionBeginUser;
360   *flux = SIG * (-emm * (PetscPowScalarInt(airtemp, 4))); /* calculates flux usinge Stefan-Boltzmann relation */
361   PetscFunctionReturn(PETSC_SUCCESS);
362 }
363 PetscErrorCode sensibleflux(PetscScalar sfctemp, PetscScalar airtemp, PetscScalar wind, PetscScalar *sheat)
364 {
365   PetscScalar density = 1;    /* air density */
366   PetscScalar Cp      = 1005; /* heat capacity for dry air */
367   PetscScalar wndmix;         /* temperature change from wind mixing: wind*Ch */
368 
369   PetscFunctionBeginUser;
370   wndmix = 0.0025 + 0.0042 * wind;                      /* regression equation valid for neutral and stable BL */
371   *sheat = density * Cp * wndmix * (airtemp - sfctemp); /* calculates sensible heat flux */
372   PetscFunctionReturn(PETSC_SUCCESS);
373 }
374 
375 PetscErrorCode latentflux(PetscScalar sfctemp, PetscScalar dewtemp, PetscScalar wind, PetscScalar pressure1, PetscScalar *latentheat)
376 {
377   PetscScalar density = 1; /* density of dry air */
378   PetscScalar q;           /* actual specific humitity */
379   PetscScalar qs;          /* saturation specific humidity */
380   PetscScalar wndmix;      /* temperature change from wind mixing: wind*Ch */
381   PetscScalar beta = .4;   /* moisture availability */
382   PetscScalar mr;          /* mixing ratio */
383   PetscScalar lhcnst;      /* latent heat of vaporization constant = 2501000 J/kg at 0c */
384                            /* latent heat of saturation const = 2834000 J/kg */
385                            /* latent heat of fusion const = 333700 J/kg */
386 
387   PetscFunctionBeginUser;
388   wind   = mph2mpers(wind);                 /* converts wind from mph to meters per second */
389   wndmix = 0.0025 + 0.0042 * wind;          /* regression equation valid for neutral BL */
390   lhcnst = Lconst(sfctemp);                 /* calculates latent heat of evaporation */
391   mr     = calcmixingr(sfctemp, pressure1); /* calculates saturation mixing ratio */
392   qs     = calc_q(mr);                      /* calculates saturation specific humidty */
393   mr     = calcmixingr(dewtemp, pressure1); /* calculates mixing ratio */
394   q      = calc_q(mr);                      /* calculates specific humidty */
395 
396   *latentheat = density * wndmix * beta * lhcnst * (q - qs); /* calculates latent heat flux */
397   PetscFunctionReturn(PETSC_SUCCESS);
398 }
399 
400 PetscErrorCode potential_temperature(PetscScalar temp, PetscScalar pressure1, PetscScalar pressure2, PetscScalar sfctemp, PetscScalar *pottemp)
401 {
402   PetscScalar kdry; /* poisson constant for dry atmosphere */
403   PetscScalar pavg; /* average atmospheric pressure */
404   /* PetscScalar mixratio; mixing ratio */
405   /* PetscScalar kmoist;   poisson constant for moist atmosphere */
406 
407   PetscFunctionBeginUser;
408   /* mixratio = calcmixingr(sfctemp,pressure1); */
409 
410   /* initialize poisson constant */
411   kdry = 0.2854;
412   /* kmoist = 0.2854*(1 - 0.24*mixratio); */
413 
414   pavg     = ((0.7 * pressure1) + pressure2) / 2;             /* calculates simple average press */
415   *pottemp = temp * (PetscPowScalar(pressure1 / pavg, kdry)); /* calculates potential temperature */
416   PetscFunctionReturn(PETSC_SUCCESS);
417 }
418 extern PetscScalar calcmixingr(PetscScalar dtemp, PetscScalar pressure1)
419 {
420   PetscScalar e;        /* vapor pressure */
421   PetscScalar mixratio; /* mixing ratio */
422 
423   dtemp    = dtemp - 273;                                                  /* converts from Kelvin to Celsius */
424   e        = 6.11 * (PetscPowScalar(10, (7.5 * dtemp) / (237.7 + dtemp))); /* converts from dew point temp to vapor pressure */
425   e        = e * 100;                                                      /* converts from hPa to Pa */
426   mixratio = (0.622 * e) / (pressure1 - e);                                /* computes mixing ratio */
427   mixratio = mixratio * 1;                                                 /* convert to g/Kg */
428 
429   return mixratio;
430 }
431 extern PetscScalar calc_q(PetscScalar rv)
432 {
433   PetscScalar specific_humidity;     /* define specific humidity variable */
434   specific_humidity = rv / (1 + rv); /* calculates specific humidity */
435   return specific_humidity;
436 }
437 
438 PetscErrorCode calc_gflux(PetscScalar sfctemp, PetscScalar deep_grnd_temp, PetscScalar *Gflux)
439 {
440   PetscScalar k;                       /* thermal conductivity parameter */
441   PetscScalar n                = 0.38; /* value of soil porosity */
442   PetscScalar dz               = 1;    /* depth of layer between soil surface and deep soil layer */
443   PetscScalar unit_soil_weight = 2700; /* unit soil weight in kg/m^3 */
444 
445   PetscFunctionBeginUser;
446   k      = ((0.135 * (1 - n) * unit_soil_weight) + 64.7) / (unit_soil_weight - (0.947 * (1 - n) * unit_soil_weight)); /* dry soil conductivity */
447   *Gflux = (k * (deep_grnd_temp - sfctemp) / dz);                                                                     /* calculates flux from deep ground layer */
448   PetscFunctionReturn(PETSC_SUCCESS);
449 }
450 extern PetscScalar emission(PetscScalar pwat)
451 {
452   PetscScalar emma;
453 
454   emma = 0.725 + 0.17 * PetscLog10Real(PetscRealPart(pwat));
455 
456   return emma;
457 }
458 extern PetscScalar cloud(PetscScalar fract)
459 {
460   PetscScalar emma = 0;
461 
462   /* modifies radiative balance depending on cloud cover */
463   if (fract >= 0.9) emma = 1;
464   else if (0.9 > fract && fract >= 0.8) emma = 0.9;
465   else if (0.8 > fract && fract >= 0.7) emma = 0.85;
466   else if (0.7 > fract && fract >= 0.6) emma = 0.75;
467   else if (0.6 > fract && fract >= 0.5) emma = 0.65;
468   else if (0.4 > fract && fract >= 0.3) emma = emma * 1.086956;
469   return emma;
470 }
471 extern PetscScalar Lconst(PetscScalar sfctemp)
472 {
473   PetscScalar Lheat;
474   sfctemp -= 273;                               /* converts from kelvin to celsius */
475   Lheat = 4186.8 * (597.31 - 0.5625 * sfctemp); /* calculates latent heat constant */
476   return Lheat;
477 }
478 extern PetscScalar mph2mpers(PetscScalar wind)
479 {
480   wind = ((wind * 1.6 * 1000) / 3600); /* converts wind from mph to meters per second */
481   return wind;
482 }
483 extern PetscScalar fahr_to_cel(PetscScalar temp)
484 {
485   temp = (5 * (temp - 32)) / 9; /* converts from farhrenheit to celsius */
486   return temp;
487 }
488 extern PetscScalar cel_to_fahr(PetscScalar temp)
489 {
490   temp = ((temp * 9) / 5) + 32; /* converts from celsius to farhrenheit */
491   return temp;
492 }
493 PetscErrorCode readinput(struct in *put)
494 {
495   int    i;
496   char   x;
497   FILE  *ifp;
498   double tmp;
499 
500   PetscFunctionBeginUser;
501   ifp = fopen("ex5_control.txt", "r");
502   PetscCheck(ifp, PETSC_COMM_SELF, PETSC_ERR_FILE_OPEN, "Unable to open input file");
503   for (i = 0; i < 110; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
504   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
505   put->Ts = tmp;
506 
507   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
508   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
509   put->Td = tmp;
510 
511   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
512   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
513   put->Ta = tmp;
514 
515   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
516   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
517   put->Tc = tmp;
518 
519   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
520   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
521   put->fr = tmp;
522 
523   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
524   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
525   put->wnd = tmp;
526 
527   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
528   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
529   put->pwt = tmp;
530 
531   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
532   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
533   put->wndDir = tmp;
534 
535   for (i = 0; i < 43; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
536   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
537   put->time = tmp;
538 
539   for (i = 0; i < 63; i++) PetscCheck(fscanf(ifp, "%c", &x) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
540   PetscCheck(fscanf(ifp, "%lf", &tmp) == 1, PETSC_COMM_SELF, PETSC_ERR_FILE_READ, "Unable to read file");
541   put->init = tmp;
542   PetscFunctionReturn(PETSC_SUCCESS);
543 }
544 
545 /* ------------------------------------------------------------------- */
546 PetscErrorCode FormInitialSolution(DM da, Vec Xglobal, PetscCtx ctx)
547 {
548   AppCtx  *user = (AppCtx *)ctx; /* user-defined application context */
549   PetscInt i, j, xs, ys, xm, ym, Mx, My;
550   Field  **X;
551 
552   PetscFunctionBeginUser;
553   PetscCall(DMDAGetInfo(da, PETSC_IGNORE, &Mx, &My, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE));
554 
555   /* Get pointers to vector data */
556   PetscCall(DMDAVecGetArray(da, Xglobal, &X));
557 
558   /* Get local grid boundaries */
559   PetscCall(DMDAGetCorners(da, &xs, &ys, NULL, &xm, &ym, NULL));
560 
561   /* Compute function over the locally owned part of the grid */
562 
563   if (user->init == 1) {
564     for (j = ys; j < ys + ym; j++) {
565       for (i = xs; i < xs + xm; i++) {
566         X[j][i].Ts = user->Ts - i * 0.0001;
567         X[j][i].Ta = X[j][i].Ts - 5;
568         X[j][i].u  = 0;
569         X[j][i].v  = 0;
570         X[j][i].p  = 1.25;
571         if ((j == 5 || j == 6) && (i == 4 || i == 5)) X[j][i].p += 0.00001;
572         if ((j == 5 || j == 6) && (i == 12 || i == 13)) X[j][i].p += 0.00001;
573       }
574     }
575   } else {
576     for (j = ys; j < ys + ym; j++) {
577       for (i = xs; i < xs + xm; i++) {
578         X[j][i].Ts = user->Ts;
579         X[j][i].Ta = X[j][i].Ts - 5;
580         X[j][i].u  = 0;
581         X[j][i].v  = 0;
582         X[j][i].p  = 1.25;
583       }
584     }
585   }
586 
587   /* Restore vectors */
588   PetscCall(DMDAVecRestoreArray(da, Xglobal, &X));
589   PetscFunctionReturn(PETSC_SUCCESS);
590 }
591 
592 /*
593    RhsFunc - Evaluates nonlinear function F(u).
594 
595    Input Parameters:
596 .  ts - the TS context
597 .  t - current time
598 .  Xglobal - input vector
599 .  F - output vector
600 .  ptr - optional user-defined context, as set by SNESSetFunction()
601 
602    Output Parameter:
603 .  F - rhs function vector
604  */
605 PetscErrorCode RhsFunc(TS ts, PetscReal t, Vec Xglobal, Vec F, PetscCtx ctx)
606 {
607   AppCtx     *user = (AppCtx *)ctx; /* user-defined application context */
608   DM          da   = user->da;
609   PetscInt    i, j, Mx, My, xs, ys, xm, ym;
610   PetscReal   dhx, dhy;
611   Vec         localT;
612   Field     **X, **Frhs;                                            /* structures that contain variables of interest and left hand side of governing equations respectively */
613   PetscScalar csoil          = user->csoil;                         /* heat constant for layer */
614   PetscScalar dzlay          = user->dzlay;                         /* thickness of top soil layer */
615   PetscScalar emma           = user->emma;                          /* emission parameter */
616   PetscScalar wind           = user->wind;                          /* wind speed */
617   PetscScalar dewtemp        = user->dewtemp;                       /* dew point temperature (moisture in air) */
618   PetscScalar pressure1      = user->pressure1;                     /* sea level pressure */
619   PetscScalar airtemp        = user->airtemp;                       /* temperature of air near boundary layer inversion */
620   PetscScalar fract          = user->fract;                         /* fraction of the sky covered by clouds */
621   PetscScalar Tc             = user->Tc;                            /* temperature at base of lowest cloud layer */
622   PetscScalar lat            = user->lat;                           /* latitude */
623   PetscScalar Cp             = 1005.7;                              /* specific heat of air at constant pressure */
624   PetscScalar Rd             = 287.058;                             /* gas constant for dry air */
625   PetscScalar diffconst      = 1000;                                /* diffusion coefficient */
626   PetscScalar f              = 2 * 0.0000727 * PetscSinScalar(lat); /* coriolis force */
627   PetscScalar deep_grnd_temp = user->deep_grnd_temp;                /* temp in lowest ground layer */
628   PetscScalar Ts, u, v, p;
629   PetscScalar u_abs, u_plus, u_minus, v_abs, v_plus, v_minus;
630 
631   PetscScalar sfctemp1, fsfc1, Ra;
632   PetscScalar sheat;      /* sensible heat flux */
633   PetscScalar latentheat; /* latent heat flux */
634   PetscScalar groundflux; /* flux from conduction of deep ground layer in contact with top soil */
635   PetscInt    xend, yend;
636 
637   PetscFunctionBeginUser;
638   PetscCall(DMGetLocalVector(da, &localT));
639   PetscCall(DMDAGetInfo(da, PETSC_IGNORE, &Mx, &My, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE, PETSC_IGNORE));
640 
641   dhx = (PetscReal)(Mx - 1) / (5000 * (Mx - 1)); /* dhx = 1/dx; assume 2D space domain: [0.0, 1.e5] x [0.0, 1.e5] */
642   dhy = (PetscReal)(My - 1) / (5000 * (Mx - 1)); /* dhy = 1/dy; */
643 
644   /*
645      Scatter ghost points to local vector,using the 2-step process
646         DAGlobalToLocalBegin(),DAGlobalToLocalEnd().
647      By placing code between these two statements, computations can be
648      done while messages are in transition.
649   */
650   PetscCall(DMGlobalToLocalBegin(da, Xglobal, INSERT_VALUES, localT));
651   PetscCall(DMGlobalToLocalEnd(da, Xglobal, INSERT_VALUES, localT));
652 
653   /* Get pointers to vector data */
654   PetscCall(DMDAVecGetArrayRead(da, localT, &X));
655   PetscCall(DMDAVecGetArray(da, F, &Frhs));
656 
657   /* Get local grid boundaries */
658   PetscCall(DMDAGetCorners(da, &xs, &ys, NULL, &xm, &ym, NULL));
659 
660   /* Compute function over the locally owned part of the grid */
661   /* the interior points */
662   xend = xs + xm;
663   yend = ys + ym;
664   for (j = ys; j < yend; j++) {
665     for (i = xs; i < xend; i++) {
666       Ts = X[j][i].Ts;
667       u  = X[j][i].u;
668       v  = X[j][i].v;
669       p  = X[j][i].p; /*P = X[j][i].P; */
670 
671       sfctemp1 = (double)Ts;
672       PetscCall(calcfluxs(sfctemp1, airtemp, emma, fract, Tc, &fsfc1));       /* calculates surface net radiative flux */
673       PetscCall(sensibleflux(sfctemp1, airtemp, wind, &sheat));               /* calculate sensible heat flux */
674       PetscCall(latentflux(sfctemp1, dewtemp, wind, pressure1, &latentheat)); /* calculates latent heat flux */
675       PetscCall(calc_gflux(sfctemp1, deep_grnd_temp, &groundflux));           /* calculates flux from earth below surface soil layer by conduction */
676       PetscCall(calcfluxa(sfctemp1, airtemp, emma, &Ra));                     /* Calculates the change in downward radiative flux */
677       fsfc1 = fsfc1 + latentheat + sheat + groundflux;                        /* adds radiative, sensible heat, latent heat, and ground heat flux yielding net flux */
678 
679       /* convective coefficients for upwinding */
680       u_abs   = PetscAbsScalar(u);
681       u_plus  = .5 * (u + u_abs); /* u if u>0; 0 if u<0 */
682       u_minus = .5 * (u - u_abs); /* u if u <0; 0 if u>0 */
683 
684       v_abs   = PetscAbsScalar(v);
685       v_plus  = .5 * (v + v_abs); /* v if v>0; 0 if v<0 */
686       v_minus = .5 * (v - v_abs); /* v if v <0; 0 if v>0 */
687 
688       /* Solve governing equations */
689       /* P = p*Rd*Ts; */
690 
691       /* du/dt -> time change of east-west component of the wind */
692       Frhs[j][i].u = -u_plus * (u - X[j][i - 1].u) * dhx - u_minus * (X[j][i + 1].u - u) * dhx                                             /* - u(du/dx) */
693                    - v_plus * (u - X[j - 1][i].u) * dhy - v_minus * (X[j + 1][i].u - u) * dhy                                              /* - v(du/dy) */
694                    - (Rd / p) * (Ts * (X[j][i + 1].p - X[j][i - 1].p) * 0.5 * dhx + p * 0 * (X[j][i + 1].Ts - X[j][i - 1].Ts) * 0.5 * dhx) /* -(R/p)[Ts(dp/dx)+ p(dTs/dx)] */
695                                                                                                                                            /*                     -(1/p)*(X[j][i+1].P - X[j][i-1].P)*dhx */
696                    + f * v;
697 
698       /* dv/dt -> time change of north-south component of the wind */
699       Frhs[j][i].v = -u_plus * (v - X[j][i - 1].v) * dhx - u_minus * (X[j][i + 1].v - v) * dhx                                             /* - u(dv/dx) */
700                    - v_plus * (v - X[j - 1][i].v) * dhy - v_minus * (X[j + 1][i].v - v) * dhy                                              /* - v(dv/dy) */
701                    - (Rd / p) * (Ts * (X[j + 1][i].p - X[j - 1][i].p) * 0.5 * dhy + p * 0 * (X[j + 1][i].Ts - X[j - 1][i].Ts) * 0.5 * dhy) /* -(R/p)[Ts(dp/dy)+ p(dTs/dy)] */
702                                                                                                                                            /*                     -(1/p)*(X[j+1][i].P - X[j-1][i].P)*dhy */
703                    - f * u;
704 
705       /* dT/dt -> time change of temperature */
706       Frhs[j][i].Ts = (fsfc1 / (csoil * dzlay))                                                    /* Fnet/(Cp*dz)  diabatic change in T */
707                     - u_plus * (Ts - X[j][i - 1].Ts) * dhx - u_minus * (X[j][i + 1].Ts - Ts) * dhx /* - u*(dTs/dx)  advection x */
708                     - v_plus * (Ts - X[j - 1][i].Ts) * dhy - v_minus * (X[j + 1][i].Ts - Ts) * dhy /* - v*(dTs/dy)  advection y */
709                     + diffconst * ((X[j][i + 1].Ts - 2 * Ts + X[j][i - 1].Ts) * dhx * dhx          /* + D(Ts_xx + Ts_yy)  diffusion */
710                                    + (X[j + 1][i].Ts - 2 * Ts + X[j - 1][i].Ts) * dhy * dhy);
711 
712       /* dp/dt -> time change of */
713       Frhs[j][i].p = -u_plus * (p - X[j][i - 1].p) * dhx - u_minus * (X[j][i + 1].p - p) * dhx /* - u*(dp/dx) */
714                    - v_plus * (p - X[j - 1][i].p) * dhy - v_minus * (X[j + 1][i].p - p) * dhy; /* - v*(dp/dy) */
715 
716       Frhs[j][i].Ta = Ra / Cp; /* dTa/dt time change of air temperature */
717     }
718   }
719 
720   /* Restore vectors */
721   PetscCall(DMDAVecRestoreArrayRead(da, localT, &X));
722   PetscCall(DMDAVecRestoreArray(da, F, &Frhs));
723   PetscCall(DMRestoreLocalVector(da, &localT));
724   PetscFunctionReturn(PETSC_SUCCESS);
725 }
726 
727 PetscErrorCode Monitor(TS ts, PetscInt step, PetscReal time, Vec T, PetscCtx ctx)
728 {
729   const PetscScalar *array;
730   MonitorCtx        *user   = (MonitorCtx *)ctx;
731   PetscViewer        viewer = user->drawviewer;
732   PetscReal          norm;
733 
734   PetscFunctionBeginUser;
735   PetscCall(VecNorm(T, NORM_INFINITY, &norm));
736 
737   if (step % user->interval == 0) {
738     PetscCall(VecGetArrayRead(T, &array));
739     PetscCall(PetscPrintf(PETSC_COMM_WORLD, "step %" PetscInt_FMT ", time %8.1f,  %6.4f, %6.4f, %6.4f, %6.4f, %6.4f, %6.4f\n", step, (double)time, (double)(((array[0] - 273) * 9) / 5 + 32), (double)(((array[1] - 273) * 9) / 5 + 32), (double)array[2], (double)array[3], (double)array[4], (double)array[5]));
740     PetscCall(VecRestoreArrayRead(T, &array));
741   }
742 
743   if (user->drawcontours) PetscCall(VecView(T, viewer));
744   PetscFunctionReturn(PETSC_SUCCESS);
745 }
746 
747 /*TEST
748 
749    build:
750       requires: !complex !single
751 
752    test:
753       args: -ts_max_steps 130 -monitor_interval 60
754       output_file: output/ex5.out
755       requires: !complex !single
756       localrunfiles: ex5_control.txt
757 
758    test:
759       suffix: 2
760       nsize: 4
761       args: -ts_max_steps 130 -monitor_interval 60
762       output_file: output/ex5.out
763       localrunfiles: ex5_control.txt
764       requires: !complex !single
765 
766    # Test TSPruneIJacobianColor() for improved FD coloring
767    test:
768       suffix: 3
769       nsize: 4
770       args: -ts_max_steps 130 -monitor_interval 60 -prune_jacobian -mat_coloring_view
771       requires: !complex !single
772       localrunfiles: ex5_control.txt
773 
774 TEST*/
775