Actual source code: ex2.c

  1: static char help[] = "Tests PetscRandom functions.\n\n";

  3: #include <petscsys.h>

  5: #define PETSC_MAXBSIZE 40
  6: #define DATAFILENAME   "ex2_stock.txt"

  8: struct himaInfoTag {
  9:   PetscInt   n;
 10:   PetscReal  r;
 11:   PetscReal  dt;
 12:   PetscInt   totalNumSim;
 13:   PetscReal *St0;
 14:   PetscReal *vol;
 15: };
 16: typedef struct himaInfoTag himaInfo;

 18: PetscErrorCode readData(MPI_Comm, himaInfo *);
 19: PetscReal      mcVal(PetscReal, PetscReal, PetscReal, PetscReal, PetscReal);
 20: void           exchangeVal(PetscReal *, PetscReal *);
 21: PetscReal      basketPayoff(PetscReal[], PetscReal[], PetscInt, PetscReal, PetscReal, PetscReal[]);
 22: PetscErrorCode stdNormalArray(PetscReal *, PetscInt, PetscRandom);
 23: PetscInt       divWork(PetscMPIInt, PetscInt, PetscMPIInt);

 25: /*
 26:    Contributed by Xiaoyan Zeng <zengxia@iit.edu> and Liu, Kwong Ip" <kiliu@math.hkbu.edu.hk>

 28:    Example of usage:
 29:      mpiexec -n 4 ./ex2 -num_of_stocks 30 -interest_rate 0.4 -time_interval 0.01 -num_of_simulations 10000
 30: */

 32: int main(int argc, char *argv[])
 33: {
 34:   PetscReal     r, dt;
 35:   PetscInt      n;
 36:   unsigned long i, myNumSim, totalNumSim, numdim;
 37:   PetscReal    *vol, *St0, x, totalx;
 38:   PetscMPIInt   size, rank;
 39:   PetscReal    *eps;
 40:   himaInfo      hinfo;
 41:   PetscRandom   ran;

 43:   PetscFunctionBeginUser;
 44:   PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
 45:   PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &ran));
 46:   PetscCall(PetscRandomSetFromOptions(ran));

 48:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 49:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));

 51:   hinfo.n           = 31;
 52:   hinfo.r           = 0.04;
 53:   hinfo.dt          = 1.0 / 12; /* a month as a period */
 54:   hinfo.totalNumSim = 1000;

 56:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-num_of_stocks", &(hinfo.n), NULL));
 57:   PetscCheck(hinfo.n >= 1 && hinfo.n <= 31, PETSC_COMM_SELF, PETSC_ERR_SUP, "Only 31 stocks listed in stock.txt. num_of_stocks %" PetscInt_FMT " must between 1 and 31", hinfo.n);
 58:   PetscCall(PetscOptionsGetReal(NULL, NULL, "-interest_rate", &(hinfo.r), NULL));
 59:   PetscCall(PetscOptionsGetReal(NULL, NULL, "-time_interval", &(hinfo.dt), NULL));
 60:   PetscCall(PetscOptionsGetInt(NULL, NULL, "-num_of_simulations", &(hinfo.totalNumSim), NULL));

 62:   n           = hinfo.n;
 63:   r           = hinfo.r;
 64:   dt          = hinfo.dt;
 65:   totalNumSim = hinfo.totalNumSim;
 66:   PetscCall(PetscMalloc1(2 * n + 1, &hinfo.vol));
 67:   vol = hinfo.vol;
 68:   St0 = hinfo.St0 = hinfo.vol + n;
 69:   PetscCall(readData(PETSC_COMM_WORLD, &hinfo));

 71:   numdim = n * (n + 1) / 2;
 72:   if (numdim % 2 == 1) numdim++;
 73:   PetscCall(PetscMalloc1(numdim, &eps));

 75:   myNumSim = divWork(rank, totalNumSim, size);

 77:   x = 0;
 78:   for (i = 0; i < myNumSim; i++) {
 79:     PetscCall(stdNormalArray(eps, numdim, ran));
 80:     x += basketPayoff(vol, St0, n, r, dt, eps);
 81:   }

 83:   PetscCallMPI(MPI_Reduce(&x, &totalx, 1, MPIU_REAL, MPIU_SUM, 0, PETSC_COMM_WORLD));
 84:   /* payoff = exp(-r*dt*n)*(totalx/totalNumSim);
 85:   ierr = PetscPrintf(PETSC_COMM_WORLD,"Option price = $%.3f using %ds of %s computation with %d %s for %d stocks, %d trading period per year, %.2f%% interest rate\n",
 86:    payoff,(int)(stop - start),"parallel",size,"processors",n,(int)(1/dt),r); */

 88:   PetscCall(PetscFree(vol));
 89:   PetscCall(PetscFree(eps));
 90:   PetscCall(PetscRandomDestroy(&ran));
 91:   PetscCall(PetscFinalize());
 92:   return 0;
 93: }

 95: PetscErrorCode stdNormalArray(PetscReal *eps, PetscInt numdim, PetscRandom ran)
 96: {
 97:   PetscInt    i;
 98:   PetscScalar u1, u2;
 99:   PetscReal   t;

101:   PetscFunctionBegin;
102:   for (i = 0; i < numdim; i += 2) {
103:     PetscCall(PetscRandomGetValue(ran, &u1));
104:     PetscCall(PetscRandomGetValue(ran, &u2));

106:     t          = PetscSqrtReal(-2 * PetscLogReal(PetscRealPart(u1)));
107:     eps[i]     = t * PetscCosReal(2 * PETSC_PI * PetscRealPart(u2));
108:     eps[i + 1] = t * PetscSinReal(2 * PETSC_PI * PetscRealPart(u2));
109:   }
110:   PetscFunctionReturn(PETSC_SUCCESS);
111: }

113: PetscReal basketPayoff(PetscReal vol[], PetscReal St0[], PetscInt n, PetscReal r, PetscReal dt, PetscReal eps[])
114: {
115:   PetscReal Stk[PETSC_MAXBSIZE], temp;
116:   PetscReal payoff;
117:   PetscInt  maxk, i, j;
118:   PetscInt  pointcount = 0;

120:   for (i = 0; i < n; i++) Stk[i] = St0[i];

122:   for (i = 0; i < n; i++) {
123:     maxk = 0;
124:     for (j = 0; j < (n - i); j++) {
125:       Stk[j] = mcVal(Stk[j], r, vol[j], dt, eps[pointcount++]);
126:       if ((Stk[j] / St0[j]) > (Stk[maxk] / St0[maxk])) maxk = j;
127:     }
128:     exchangeVal(Stk + j - 1, Stk + maxk);
129:     exchangeVal(St0 + j - 1, St0 + maxk);
130:     exchangeVal(vol + j - 1, vol + maxk);
131:   }

133:   payoff = 0;
134:   for (i = 0; i < n; i++) {
135:     temp = (Stk[i] / St0[i]) - 1;
136:     if (temp > 0) payoff += temp;
137:   }
138:   return payoff;
139: }

141: PetscErrorCode readData(MPI_Comm comm, himaInfo *hinfo)
142: {
143:   PetscInt    i;
144:   FILE       *fd;
145:   char        temp[50];
146:   PetscMPIInt rank;
147:   PetscReal  *v = hinfo->vol, *t = hinfo->St0;
148:   PetscInt    num = hinfo->n;

150:   PetscFunctionBeginUser;
151:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
152:   if (rank == 0) {
153:     PetscCall(PetscFOpen(PETSC_COMM_SELF, DATAFILENAME, "r", &fd));
154:     for (i = 0; i < num; i++) {
155:       double vv, tt;
156:       PetscCheck(fscanf(fd, "%s%lf%lf", temp, &vv, &tt) == 3, PETSC_COMM_SELF, PETSC_ERR_FILE_UNEXPECTED, "Badly formatted input file");
157:       v[i] = vv;
158:       t[i] = tt;
159:     }
160:     fclose(fd);
161:   }
162:   PetscCallMPI(MPI_Bcast(v, 2 * num, MPIU_REAL, 0, PETSC_COMM_WORLD));
163:   /* ierr = PetscPrintf(PETSC_COMM_SELF,"[%d] vol %g, ... %g; St0 %g, ... %g\n",rank,hinfo->vol[0],hinfo->vol[num-1],hinfo->St0 [0],hinfo->St0[num-1]); */
164:   PetscFunctionReturn(PETSC_SUCCESS);
165: }

167: void exchangeVal(PetscReal *a, PetscReal *b)
168: {
169:   PetscReal t;

171:   t  = *a;
172:   *a = *b;
173:   *b = t;
174: }

176: PetscReal mcVal(PetscReal St, PetscReal r, PetscReal vol, PetscReal dt, PetscReal eps)
177: {
178:   return (St * PetscExpReal((r - 0.5 * vol * vol) * dt + vol * PetscSqrtReal(dt) * eps));
179: }

181: PetscInt divWork(PetscMPIInt id, PetscInt num, PetscMPIInt size)
182: {
183:   PetscInt numit;

185:   numit = (PetscInt)(((PetscReal)num) / size);
186:   numit++;
187:   return numit;
188: }

190: /*TEST

192:    test:
193:       nsize: 2
194:       output_file: output/ex1_1.out
195:       localrunfiles: ex2_stock.txt

197: TEST*/