rtsIDe (1158448), страница 25

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for (it = 1; it <= itmax; it++)

{

/* Parallel loop to calculate maximal deviation

of the grid function in variable eps

(parallel loop with base array Ahdr) */

plref = crtpl_ (&Rank2);

iiniti[0] = 1;

iiniti[1] = 1;

ilasti[0] = k - 2;

ilasti[1] = k - 2;

mappl_ (&plref, (PatternRef *)Ahdr, axis, coeff, cnst, lvaddr,

lvtype, iiniti, ilasti, istep, oiniti, olasti, ostep);

eps = 0.;

while (dopl_ (&plref))

for ( j = oiniti[0]; j <= olasti[0]; j += ostep[0] )

for ( i = oiniti[1]; i <= olasti[1]; i += ostep[1] )

{ eps = max(eps, dvm_abs( DAElm2(Bhdr,float,j,i) -

DAElm2(Ahdr,float,j,i) ));

DAElm2(Ahdr, float, j, i) =

DAElm2(Bhdr, float, j, i);

}

endpl_ (&plref);

/* Calculation of reductional maximum */

strtrd_ (&rgref);

waitrd_ (&rgref);

/* Shadow edges exchange */

strtsh_ (&shgref);

waitsh_ (&shgref);

/* Parallel loop to calculate new values

of the grid function in array bhdr

(parallel loop with base array Bhdr) */

plref = crtpl_ (&Rank2);

mappl_ (&plref, (PatternRef *)Bhdr, axis, coeff, cnst, lvaddr,

lvtype, iiniti, ilasti, istep, oiniti, olasti, ostep);

while (dopl_ (&plref))

for ( j = oiniti[0]; j <= olasti[0]; j += ostep[0] )

for ( i = oiniti[1]; i <= olasti[1]; i += ostep[1] )

DAElm2(Bhdr, float, j, i) =

( DAElm2(Ahdr, float, j, i-1) +

DAElm2(Ahdr, float, j-1, i) +

DAElm2(Ahdr, float, j, i+1) +

DAElm2(Ahdr, float, j+1, i) ) / 4.f;

endpl_ (&plref);

/* Printing current deviation of grid function */

dvm_printf("IT = %ld EPS = %e\n", it, eps);

if(eps < maxeps)

break; /* exit, if specified precision is achieved */

}

/* END OF MAIN ITERATION LOOP */

/* Writing solution in the file

and end of work with Run-Time System */

OutFile = dvm_fopen("jacobi.out", "w+b");

if(OutFile)

{ dvm_dfwrite(Bhdr, 0, OutFile);

dvm_fclose(OutFile);

}

lexit_ (&UserRes);

return (int)UserRes;

}

19.2Parallel loop with regular data dependence between iterations

The (C and Fortran) programs, considered below, are the examples of implementation of parallel loop with data (flow) dependence and anti-dependence between iterations using Run-Time System functions. The parallel loop is two-dimensional loop of the form

Where:

PROGRAM IN FORTRAM LANGUAGE

program across

integer linit, lexit,getam, getps, crtamv, distr, crtda, align,

+ crtpl, dvmadr, mappl, endpl, dopl,

+ crtshg, inssh, insshd, strtsh, recvsh, sendsh, waitsh

real bptr(1)

integer dvm

integer amref, psref, mvref, plref, shgref

integer amdim(2), disaxs(2), dispar(2)

integer lshwd(2), hshwd(2), shsign(2), axis(2), coeff(2),

+ const(2)

integer lvaddr(2), lvtype(2), iiniti(2), ilasti(2), istep(2)

integer oiniti(2), olasti(2), ostep(2)

integer FDL1, FDL2, ADL1, ADL2, finssh

C Size of each array dimension

C with regular data dependence

parameter (k = 200)

C Header of array with regular data dependence

integer ahdr(6)

ahdr(5) = 1

ahdr(6) = 1

C Length of data dependence for dimension 1

FDL1 = 4

C Length of data dependence for dimension 2

FDL2 = 3

C Length of data anti-dependence for dimension 1

ADL1 = 2

C Length of data anti-dependence for dimension 2

ADL2 = 1

C Flag to use inssh_ function to registrate array

C in shadow edge group;

C If finssh=0, insshd_ function is used

finssh = 0

C Run-Time System initialization

dvm = linit (1)

C Creating abstract machine representation and

C its mapping on processor subsystem

amref = getam ()

psref = getps (amref)

amdim(1) = k

amdim(2) = k

mvref = crtamv (amref, 2, amdim,0)

disaxs(1) = 1

disaxs(2) = 2

dispar(1) = 0

dispar(2) = 0

dvm = distr (mvref, psref, 2, disaxs, dispar)

C Creation and distribution of array

C with regular data dependence

C Width of low shadow edge for dimension 1 is

C length of data dependence for dimension 1

lshwd(1) = FDL1

C Width of low shadow edge for dimension 2 is

C length of data dependence for dimension 2

lshwd(2) = FDL2

C Width of high shadow edge for dimension 1 is

C length of data anti-dependence for dimension 1

hshwd(1) = ADL1

C Width of high shadow edge for dimension 2 is

C length of data anti-dependence for dimension 2

hshwd(2) = ADL2

dvm = crtda (ahdr, 1, bptr, 2, 4, amdim, 0, 0, lshwd, hshwd)

axis(1) = 1

axis(2) = 2

coeff(1) = 1

coeff(2) = 1

const(1) = 0

const(2) = 0

dvm = align (ahdr, mvref, axis, coeff, const)

C Parallel loop of array initialization

C with regular data dependence

plref = crtpl (2)

lvaddr(1) = dvmadr (j)

lvaddr(2) = dvmadr (i)

lvtype(1) = 1

lvtype(2) = 1

iiniti(1) = 0

iiniti(2) = 0

ilasti(1) = k - 1

ilasti(2) = k - 1

istep(1) = 1

istep(2) = 1

dvm = mappl (plref, ahdr, axis, coeff, const, lvaddr, lvtype

+ iiniti, ilasti, istep, oiniti, olasti, ostep)

2 if (dopl (plref) .eq. 0) goto 3

do 1 j = oiniti(1), olasti(1), ostep(1)

do 1 i = oiniti(2), olasti(2), ostep(2)

bptr( ahdr(3) + 1 + i + ahdr(2) * j ) = 1.

1 continue

goto 2

3 dvm = endpl (plref)

C Creation of shadow edge group to supply

C data anti-dependence

shgref = crtshg (0)

C Zero width of low shadow edge for dimension 1

lshwd(1) = 0

C Zero width of low shadow edge for dimension 2

lshwd(2) = 0

C Width of high shadow edge for dimension 1 is

C length of data anti-dependence for dimension 1

hshwd(1) = ADL1

C Width of high shadow edge for dimension 2 is

C length of data anti-dependence for dimension 2

hshwd(2) = ADL2

dvm = inssh (shgref, ahdr, lshwd, hshwd, 0)

C Initialization of shadow edges to support

C data anti-dependence

dvm = strtsh (shgref)

dvm = waitsh (shgref)

C Creation of shadow edge group to support

C data dependence

shgref = crtshg (0)

C Width of low shadow edge for dimension 1 is

C length of data dependence for dimension 1

lshwd(1) = FDL1

C Width of low shadow edge for dimension 2 is

C length of data dependence for dimension 2

lshwd(2) = FDL2

C Zero width of high shadow edge for dimension 1

hshwd(1) = 0

C Zero width of high shadow edge for dimension 2

hshwd(2) = 0

if (finssh .eq. 0) goto 4

C inssh_ is used to registrate array in shadow edge group

dvm = inssh (shgref, ahdr, lshwd, hshwd, 0)

goto 5

C insshd_ is used to registrate array in shadow edge group

C Only low edge is used for dimensions 1 and 2

4 shsign(1) = 3

shsign(2) = 3

dvm = insshd (shgref, ahdr, lshwd, hshwd, 1, shsign)

goto 5

C Receiving imported elements

C to support data dependence

5 dvm = recvsh (shgref)

dvm = waitsh (shgref)

C PARALLEL LOOP WITH DATA DEPENDENCE AND

C ANTI-DEPENDENCE BETWEEN ITERATIONS

plref = crtpl (2)

iiniti(1) = 1

iiniti(2) = 1

ilasti(1) = k - 2

ilasti(2) = k - 2

dvm = mappl (plref, ahdr, axis, coeff, const, lvaddr, lvtype,

+ iiniti, ilasti, istep, oiniti, olasti, ostep)

6 if (dopl (plref) .eq. 0) goto 7

do 8 j = oiniti(1), olasti(1), ostep(1)

do 8 i = oiniti(2), olasti(2), ostep(2)

bptr(ahdr(3) + 1 + i + ahdr(2) * j) =

+ ( bptr(ahdr(3) + 1 + (i - FDL2) + ahdr(2) * j) +

+ bptr(ahdr(3) + 1 + i + ahdr(2) * (j - FDL1)) +

+ bptr(ahdr(3) + 1 + (i + ADL2) + ahdr(2) * j) +

+ bptr(ahdr(3) + 1 + i + ahdr(2) * (j + ADL1)) ) / 4.

8 continue

goto 6

7 dvm = endpl (plref)

C Sending exported elements

C to support data dependence

dvm = sendsh (shgref)

dvm = waitsh (shgref)

C Run-Time System termination

dvm = lexit (0)

end

PROGRAM IN C LANGUAGE

#include "dvmlib.h"

int main(int argc, char *argv[])

{

long InitPar = 0, UserRes = 0;

long StaticMV = 0, StaticDA = 0, ReDistrDA = 0,

StaticShG = 0, FullShd = 0, MaxShdCount = 1;

long ShdSignArray[2];

long i, j, Rank2 = 2, TypeSize = sizeof(float);

AMRef amref;

PSRef psref;

AMViewRef mvref;

LoopRef plref;

ShadowGroupRef fshgref, ashgref;

AddrType lvaddr[2];

long lvtype[2] = {0,0};

long amdim[2], disaxs[2], dispar[2];

long lshwdth[2], hshwdth[2], axis[2], coeff[2], cnst[2];

long iiniti[2], ilasti[2], istep[2];

long oiniti[2], olasti[2], ostep[2];

long ExtHdrSign = 0;

DVMFILE *OutFile;

long k = 200; /* size of each array dimension

with regular data dependence */

long FDL1 = 4; /* прямой зависимости length of data

dependence for dimension 1 */

long FDL2 = 3; /* length of data dependence

for dimension 2 */

long ADL1 = 2; /* length of data anti-dependence

for dimension 1 */

long ADL2 = 1; /* length of data anti-dependence

for dimension 2 */

int f_inssh = 0; /* flag to use inssh_ function to registrate

array in the shádow edge group if f_inssh = 0,

insshd_ function is used */

long Ahdr[3]; /* header of array with

regular data dependence */

rtl_init(InitPar, argc, argv); /* Run-Time System initialization */

/* Creation of abstract machine representation

and its mapping on processor subsystem */

amref = getam_ ();

psref = getps_ (&amref);

amdim[0] = k;

amdim[1] = k;

mvref = crtamv_ (&amref, &Rank2, amdim, &StaticMV);

disaxs[0] = 1;

disaxs[1] = 2;

dispar[0] = 0;

dispar[1] = 0;

distr_ (&mvref, &psref, &Rank2, disaxs, dispar);

/* Creation and distribution of array

with regular data dependence */

lshwdth[0] = FDL1; /* width of low shadow edge for dimension 1 is

Характеристики

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