A Brief Introduction to Fortran 77 - Polaris

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As an example, consider the following code segmentc = sin (d)forall i=1 <strong>to</strong> na(i) = b(i) + cend foralle = a(20)+ a(15)A simple OpenMP implementation would take the formc = sin(d)c$omp parallel private(i,il,iu)call get_limits(n,il,iu,* omp_get_num_threads(),* omp_get_thread_num())do i=il,iua(i) = b(i) + cend doc$omp end parallele = a(20) + a(15)© 1998 David A. Padua46 of 118
Notice that the first statement can be incorporated in<strong>to</strong> theparallel region. In fact, c can be declared as private assumingit is never used outside the loop.c$omp parallel private(c,i,il,iu)c= sin(d)call get_limits(n,il,iu,* omp_get_num_threads(),* omp_get_thread_num())do i=il,iua(i) = b(i) + cend doc$omp end parallele = a(20) + a(15)© 1998 David A. Padua47 of 118
Page 1 and 2: A Brief Introduction to Fortran 771
Page 3 and 4: InterpretersAn interpreter is a pro
Page 5 and 6: Source formTraditionally, Fortran s
Page 7 and 8: Lower case letters are considered e
Page 9 and 10: The form of a character constant is
Page 11 and 12: A scalar variable does not have to
Page 13 and 14: ExpressionsExpressions in Fortran c
Page 15 and 16: The logical operators are:.NOT. Log
Page 17 and 18: 3. DO statement. Iterative statemen
Page 19 and 20: Program UnitsA Fortran program alwa
Page 21 and 22: Notice that the variable y in the l
Page 23 and 24: Each read starts on the next record
Page 25 and 26: function rtflsp(func,x1,x2,xacc)par
Page 27 and 28: A Brief Introduction to Fortran 90
Page 29 and 30: IMPLICIT none29 of 118
Page 31 and 32: Array Shapes and SizesThe shape of
Page 33 and 34: Fortran 90 Intrinsic Proceduresaint
Page 35 and 36: Finer control on when an array is c
Page 37 and 38: Procedure InterfacesWhen a procedur
Page 39 and 40: Expressions in Fortran 90 may conta
Page 41 and 42: In the following compound statement
Page 43 and 44: 6.1 IntroductionOpenMP is a collect
Page 45: All variables are assumed to be sha
Page 49 and 50: 6.4 The PSINGLE directiveFinally, s
Page 51 and 52: A better example of psingle:c$ompc$
Page 53 and 54: The syntax of the pdo directive is
Page 55 and 56: 6.6 The PARALLEL DO directiveAn alt
Page 57 and 58: And the routine pdo_2 can be rewrit
Page 59 and 60: 6.7 The PSECTIONS directiveAn alter
Page 61 and 62: end© 1998 David A. Padua61 of 118
Page 63 and 64: Chapter 7. Parallel Loops in OpenMP
Page 65 and 66: Chapter 6. OpenMP65 of 118
Page 67 and 68: Another example of a race is:c$omp
Page 69 and 70: Another example is:c$ompparallel do
Page 71 and 72: 7.2 Race-free parallel loopsNext, w
Page 73 and 74: 7.3 PrivatizationSometimes the tran
Page 75 and 76: Sometimes it is necessary to privat
Page 77 and 78: One way to solve this problem is to
Page 79 and 80: Variables in lastprivate are privat
Page 81 and 82: print *,a(1),a(2)endprints1.000000
Page 83 and 84: To account for this, a and b should
Page 86 and 87: Most induction variables are quite
Page 88 and 89: Here, again, only the induction var
Page 90 and 91: The way to remove the races produce
Page 92 and 93: We can now proceed as above to obta
Page 94 and 95: However, there is a way to improve
Page 96 and 97:
Notice that now no races exist beca
Page 98 and 99:
7.6 Execution time of a parallel do
Page 100 and 101:
following time lines:abcdeDabcdeDDa
Page 102 and 103:
7.6 Critical Regions and Reductions
Page 104 and 105:
Here, we use the critical directive
Page 106 and 107:
The assumption is that it does not
Page 108 and 109:
© 1998 David A. Padua108 of 118
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A Brief Introduction to Fortran 77 - Polaris

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