| 198 |
|
static double |
| 199 |
|
min_cost(double amt2move, const double *avail, const PRICEMAT *pm, int s) |
| 200 |
|
{ |
| 201 |
+ |
const short *srow = psortrow(pm,s); |
| 202 |
+ |
const float *prow = pricerow(pm,s); |
| 203 |
|
double total_cost = 0; |
| 204 |
|
int j; |
| 203 |
– |
|
| 204 |
– |
if (amt2move <= FTINY) /* pre-emptive check */ |
| 205 |
– |
return(.0); |
| 205 |
|
/* move cheapest first */ |
| 206 |
< |
for (j = 0; j < pm->ncols && amt2move > FTINY; j++) { |
| 207 |
< |
int d = psortrow(pm,s)[j]; |
| 206 |
> |
for (j = 0; (j < pm->ncols) & (amt2move > FTINY); j++) { |
| 207 |
> |
int d = srow[j]; |
| 208 |
|
double amt = (amt2move < avail[d]) ? amt2move : avail[d]; |
| 209 |
|
|
| 210 |
< |
total_cost += amt * pricerow(pm,s)[d]; |
| 210 |
> |
total_cost += amt * prow[d]; |
| 211 |
|
amt2move -= amt; |
| 212 |
|
} |
| 213 |
|
return(total_cost); |
| 214 |
|
} |
| 215 |
|
|
| 216 |
< |
/* Take a step in migration by choosing optimal bucket to transfer */ |
| 216 |
> |
/* Compare entries by moving price */ |
| 217 |
> |
static int |
| 218 |
> |
rmovcmp(void *b, const void *p1, const void *p2) |
| 219 |
> |
{ |
| 220 |
> |
PRICEMAT *pm = (PRICEMAT *)b; |
| 221 |
> |
const short *ij1 = (const short *)p1; |
| 222 |
> |
const short *ij2 = (const short *)p2; |
| 223 |
> |
float price_diff; |
| 224 |
> |
|
| 225 |
> |
if (ij1[1] < 0) return(ij2[1] >= 0); |
| 226 |
> |
if (ij2[1] < 0) return(-1); |
| 227 |
> |
price_diff = pricerow(pm,ij1[0])[ij1[1]] - pricerow(pm,ij2[0])[ij2[1]]; |
| 228 |
> |
if (price_diff > 0) return(1); |
| 229 |
> |
if (price_diff < 0) return(-1); |
| 230 |
> |
return(0); |
| 231 |
> |
} |
| 232 |
> |
|
| 233 |
> |
/* Take a step in migration by choosing reasonable bucket to transfer */ |
| 234 |
|
static double |
| 235 |
< |
migration_step(MIGRATION *mig, double *src_rem, double *dst_rem, const PRICEMAT *pm) |
| 235 |
> |
migration_step(MIGRATION *mig, double *src_rem, double *dst_rem, PRICEMAT *pm) |
| 236 |
|
{ |
| 237 |
+ |
const int max2check = 100; |
| 238 |
|
const double maxamt = 1./(double)pm->ncols; |
| 239 |
|
const double minamt = maxamt*5e-6; |
| 240 |
|
double *src_cost; |
| 241 |
+ |
short (*rord)[2]; |
| 242 |
|
struct { |
| 243 |
|
int s, d; /* source and destination */ |
| 244 |
|
double price; /* price estimate per amount moved */ |
| 245 |
|
double amt; /* amount we can move */ |
| 246 |
|
} cur, best; |
| 247 |
< |
int i; |
| 247 |
> |
int r2check, i, ri; |
| 248 |
> |
/* |
| 249 |
> |
* Check cheapest available routes only -- a higher adjusted |
| 250 |
> |
* destination price implies that another source is closer, so |
| 251 |
> |
* we can hold off considering more expensive options until |
| 252 |
> |
* some other (hopefully better) moves have been made. |
| 253 |
> |
*/ |
| 254 |
> |
/* most promising row order */ |
| 255 |
> |
rord = (short (*)[2])malloc(sizeof(short)*2*pm->nrows); |
| 256 |
> |
if (rord == NULL) |
| 257 |
> |
goto memerr; |
| 258 |
> |
for (ri = pm->nrows; ri--; ) { |
| 259 |
> |
rord[ri][0] = ri; |
| 260 |
> |
rord[ri][1] = -1; |
| 261 |
> |
if (src_rem[ri] <= minamt) /* enough source material? */ |
| 262 |
> |
continue; |
| 263 |
> |
for (i = 0; i < pm->ncols; i++) |
| 264 |
> |
if (dst_rem[ rord[ri][1] = psortrow(pm,ri)[i] ] > minamt) |
| 265 |
> |
break; |
| 266 |
> |
if (i >= pm->ncols) { /* moved all we can? */ |
| 267 |
> |
free(rord); |
| 268 |
> |
return(.0); |
| 269 |
> |
} |
| 270 |
> |
} |
| 271 |
> |
if (pm->nrows > max2check) /* sort if too many sources */ |
| 272 |
> |
qsort_r(rord, pm->nrows, sizeof(short)*2, pm, &rmovcmp); |
| 273 |
|
/* allocate cost array */ |
| 274 |
|
src_cost = (double *)malloc(sizeof(double)*pm->nrows); |
| 275 |
< |
if (src_cost == NULL) { |
| 276 |
< |
fprintf(stderr, "%s: Out of memory in migration_step()\n", |
| 234 |
< |
progname); |
| 235 |
< |
exit(1); |
| 236 |
< |
} |
| 275 |
> |
if (src_cost == NULL) |
| 276 |
> |
goto memerr; |
| 277 |
|
for (i = pm->nrows; i--; ) /* starting costs for diff. */ |
| 278 |
|
src_cost[i] = min_cost(src_rem[i], dst_rem, pm, i); |
| 239 |
– |
|
| 279 |
|
/* find best source & dest. */ |
| 280 |
|
best.s = best.d = -1; best.price = FHUGE; best.amt = 0; |
| 281 |
< |
for (cur.s = pm->nrows; cur.s--; ) { |
| 281 |
> |
if ((r2check = pm->nrows) > max2check) |
| 282 |
> |
r2check = max2check; /* put a limit on search */ |
| 283 |
> |
for (ri = 0; ri < r2check; ri++) { /* check each source row */ |
| 284 |
|
double cost_others = 0; |
| 285 |
< |
|
| 286 |
< |
if (src_rem[cur.s] <= minamt) |
| 287 |
< |
continue; |
| 288 |
< |
/* examine cheapest dest. */ |
| 289 |
< |
for (i = 0; i < pm->ncols; i++) |
| 290 |
< |
if (dst_rem[ cur.d = psortrow(pm,cur.s)[i] ] > minamt) |
| 250 |
< |
break; |
| 251 |
< |
if (i >= pm->ncols) |
| 252 |
< |
break; |
| 253 |
< |
if ((cur.price = pricerow(pm,cur.s)[cur.d]) >= best.price) |
| 254 |
< |
continue; /* no point checking further */ |
| 285 |
> |
cur.s = rord[ri][0]; |
| 286 |
> |
if ((cur.d = rord[ri][1]) < 0 || |
| 287 |
> |
(cur.price = pricerow(pm,cur.s)[cur.d]) >= best.price) { |
| 288 |
> |
if (pm->nrows > max2check) break; /* sorted end */ |
| 289 |
> |
continue; /* else skip this one */ |
| 290 |
> |
} |
| 291 |
|
cur.amt = (src_rem[cur.s] < dst_rem[cur.d]) ? |
| 292 |
|
src_rem[cur.s] : dst_rem[cur.d]; |
| 293 |
< |
if (cur.amt > maxamt) cur.amt = maxamt; |
| 294 |
< |
dst_rem[cur.d] -= cur.amt; /* add up differential costs */ |
| 293 |
> |
/* don't just leave smidgen */ |
| 294 |
> |
if (cur.amt > maxamt*1.02) cur.amt = maxamt; |
| 295 |
> |
dst_rem[cur.d] -= cur.amt; /* add up opportunity costs */ |
| 296 |
|
for (i = pm->nrows; i--; ) |
| 297 |
|
if (i != cur.s) |
| 298 |
< |
cost_others += min_cost(src_rem[i], dst_rem, pm, i) |
| 298 |
> |
cost_others += min_cost(src_rem[i], dst_rem, pm, i) |
| 299 |
|
- src_cost[i]; |
| 300 |
|
dst_rem[cur.d] += cur.amt; /* undo trial move */ |
| 301 |
|
cur.price += cost_others/cur.amt; /* adjust effective price */ |
| 302 |
|
if (cur.price < best.price) /* are we better than best? */ |
| 303 |
< |
best = cur; |
| 303 |
> |
best = cur; |
| 304 |
|
} |
| 305 |
< |
free(src_cost); /* finish up */ |
| 306 |
< |
|
| 305 |
> |
free(src_cost); /* clean up */ |
| 306 |
> |
free(rord); |
| 307 |
|
if ((best.s < 0) | (best.d < 0)) /* nothing left to move? */ |
| 308 |
|
return(.0); |
| 309 |
|
/* else make the actual move */ |
| 311 |
|
src_rem[best.s] -= best.amt; |
| 312 |
|
dst_rem[best.d] -= best.amt; |
| 313 |
|
return(best.amt); |
| 314 |
+ |
memerr: |
| 315 |
+ |
fprintf(stderr, "%s: Out of memory in migration_step()\n", progname); |
| 316 |
+ |
exit(1); |
| 317 |
|
} |
| 318 |
|
|
| 319 |
|
/* Compute and insert migration along directed edge (may fork child) */ |
