How to speed up simple Fortran OpenMP? -

-

i have simple fortran program in main component 4-core openmp portion calculates dot product 

omp_num_threads=4 ... 30 k=1,lines   co(k)=0   si(k)=0   co_temp=0   si_temp=0  !$omp parallel private(dotprod,qcur) reduction(+:co_temp,si_temp)     40 i=1,ion_count       dotprod=(rx(k)*x(i)+ry(k)*y(i)+rz(k)*z(i))*((2*3.1415926535)/l)       co_temp=co_temp+cos(dotprod)*26 !qcur/qavg       si_temp=si_temp+sin(dotprod)*26 !qcur/qavg      40 continue  !$omp end parallel    co(k)=co_temp   si(k)=si_temp    q(k)= ( co(k),-si(k) )   s(k)= s(k) +( q(k) * conjg(q(k)) )   r(k)=r(k)+q(k) 30 continue

i'm not experienced fortran or optimization. i'm using xlf90_r file -qsmp=omp compile. 1/2 speedup when using 4 cores, else using c has gotten perfect 1/4 speedup doing same computation. same amount of time whether omp loop on 30 or 40. time around loop 30 program whole , loop takes 99.x% of time, i'm pretty sure bit bottleneck. egregious slow mistakes i've made in portion sees?

at quick glance @ code, looks each iteration of outer loop independent. make parallel loop not inner loop.

omp_num_threads=4 ... !$omp parallel private(dotprod,qcur,co_temp,si_temp) 30 k=1,lines   co(k)=0   si(k)=0   co_temp=0   si_temp=0    40 i=1,ion_count     dotprod=(rx(k)*x(i)+ry(k)*y(i)+rz(k)*z(i))*((2*3.1415926535)/l)     co_temp=co_temp+cos(dotprod)*26 !qcur/qavg     si_temp=si_temp+sin(dotprod)*26 !qcur/qavg   40 continue    co(k)=co_temp   si(k)=si_temp    q(k)= ( co(k),-si(k) )   s(k)= s(k) +( q(k) * conjg(q(k)) )   r(k)=r(k)+q(k) 30 continue !$omp end parallel

Comments

Post a Comment

Popular posts from this blog

java - Jmockit String final length method mocking Issue -

-
using jmockit 1.2 jar, trying mock string's length method getting unexpected invocation exception: failed: test java.lang.illegalstateexception: missing invocation mocked type @ point; please make sure such invocations appear after declaration of suitable mock field or parameter @ stringdemo.testa$1.<init>(testa.java:17) @ stringdemo.testa.test(testa.java:13) i using testng: @test public void test() throws exception { new expectations() { @mocked("length") string astring; { astring.length(); result = 2; } }; system.out.println(a.showa("test")); } } actual class a: public class { public static int showa(string str){ int a= str.length(); return a; } } this wrong way of recording expected results. shouldn't mock , record string's length() method, record showa() instead. here solution @suppresswarnings("unused...
Read more

What is the difference between data design and data model(ERD) -

-
i have google question , find answer in day. know, data design many many table have list column,and mark pk , fk. why er-diagram have find this? data design process of designing database. main output of data design detailed logical data model of database. some people data design includes of needed logical , physical design choices , physical storage parameters needed generate design in data definition language. technically, database analysis, database analysts (dbas) trained do. while person can both data design , database analysis, these 2 different tasks. data design models data. database analysis takes model , applies 1 or more database engines (relational, hierarchical, nosql). a logical data model 1 of main outputs of data design. data model represented entity relationship diagram, or er diagram.
Read more

ios - Can NSManagedObject conform to NSCoding -

-
i need transfer single object across device. right converting nsmanagedobject dictionary , archiving , sending nsdata. upon receiving unarchiving it. transfer nsmanagedobject archiving , unarchiving instead of creating intermediate data object. @interface test : nsmanagedobject<nscoding> @property (nonatomic, retain) nsstring * title; @end @implementation test @dynamic title; - (id)initwithcoder:(nscoder *)coder { self = [super init]; if (self) { self.title = [coder decodeobjectforkey:@"title"]; //<crash } return self; } - (void)encodewithcoder:(nscoder *)coder { [coder encodeobject:self.title forkey:@"title"]; } @end nsdata *archivedobjects = [nskeyedarchiver archiveddatawithrootobject:testobj]; nsdata *objectsdata = archivedobjects; if ([objectsdata length] > 0) { nsarray *objects = [nskeyedunarchiver unarchiveobjectwithdata:objectsdata]; } the problem above code is. crashes @ self.title in initwithcoder sa...
Read more