Actual source code: ex1f90.F
1: !
2: !
3: !/*T
4: ! Concepts: vectors^using basic vector routines;
5: ! Concepts: Fortran90^using basic vector routines;
6: ! Processors: n
7: !T*/
8: !
9: ! -----------------------------------------------------------------------
11: program main
12: implicit none
14: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
15: ! Include files
16: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
17: !
18: ! The following include statements are required for Fortran programs
19: ! that use PETSc vectors:
20: ! petsc.h - base PETSc routines
21: ! petscvec.h - vectors
22: ! petscvec.h90 - to allow access to Fortran90 features of vectors
23: !
24: ! Additional include statements may be needed if using additional
25: ! PETSc routines in a Fortran program, e.g.,
26: ! petscviewer.h - viewers
27: ! petscis.h - index sets
28: !
29: #include include/finclude/petsc.h
30: #include include/finclude/petscvec.h
31: #include "include/finclude/petscvec.h90"
32: !
33: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
34: ! Variable declarations
35: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
36: !
37: ! Variables:
38: ! x, y, w - vectors
39: ! z - array of vectors
40: !
41: Vec x,y,w
42: Vec, pointer :: z(:)
43: double precision norm,v,v1,v2
44: integer n,ierr,flg,rank
45: PetscScalar one,two,three
46: PetscScalar dots(3),dot
48: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
49: ! Beginning of program
50: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
52: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
53: one = 1.0
54: two = 2.0
55: three = 3.0
56: n = 20
57: call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',n,flg,ierr)
58: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
60: ! Create a vector, specifying only its global dimension.
61: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
62: ! the vector format (currently parallel
63: ! or sequential) is determined at runtime. Also, the parallel
64: ! partitioning of the vector is determined by PETSc at runtime.
65: !
66: ! Routines for creating particular vector types directly are:
67: ! VecCreateSeq() - uniprocessor vector
68: ! VecCreateMPI() - distributed vector, where the user can
69: ! determine the parallel partitioning
71: call VecCreate(PETSC_COMM_WORLD,x,ierr)
72: call VecSetSizes(x,PETSC_DECIDE,n,ierr)
73: call VecSetFromOptions(x,ierr)
75: ! Duplicate some work vectors (of the same format and
76: ! partitioning as the initial vector).
78: call VecDuplicate(x,y,ierr)
79: call VecDuplicate(x,w,ierr)
81: ! Duplicate more work vectors (of the same format and
82: ! partitioning as the initial vector). Here we duplicate
83: ! an array of vectors, which is often more convenient than
84: ! duplicating individual ones.
86: call VecDuplicateVecsF90(x,3,z,ierr)
88: ! Set the vectors to entries to a constant value.
90: call VecSet(x,one,ierr)
91: call VecSet(y,two,ierr)
92: call VecSet(z(1),one,ierr)
93: call VecSet(z(2),two,ierr)
94: call VecSet(z(3),three,ierr)
96: ! Demonstrate various basic vector routines.
98: call VecDot(x,x,dot,ierr)
99: call VecMDot(x,3,z,dots,ierr)
101: ! Note: If using a complex numbers version of PETSc, then
102: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
103: ! (when using real numbers) it is undefined.
105: if (rank .eq. 0) then
106: #if defined(PETSC_USE_COMPLEX)
107: write(6,100) int(PetscRealPart(dot))
108: write(6,110) int(PetscRealPart(dots(1))), &
109: & int(PetscRealPart(dots(2))), &
110: & int(PetscRealPart(dots(3)))
111: #else
112: write(6,100) int(dot)
113: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
114: #endif
115: write(6,120)
116: endif
117: 100 format ("Vector length ",i6)
118: 110 format ("Vector length ",3(i6))
119: 120 format ("All other values should be near zero")
121: call VecScale(x,two,ierr)
122: call VecNorm(x,NORM_2,norm,ierr)
123: v = norm-2.0*sqrt(dble(n))
124: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
125: if (rank .eq. 0) write(6,130) v
126: 130 format ("VecScale ",1pe8.2)
128: call VecCopy(x,w,ierr)
129: call VecNorm(w,NORM_2,norm,ierr)
130: v = norm-2.0*sqrt(dble(n))
131: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
132: if (rank .eq. 0) write(6,140) v
133: 140 format ("VecCopy ",1pe8.2)
135: call VecAXPY(y,three,x,ierr)
136: call VecNorm(y,NORM_2,norm,ierr)
137: v = norm-8.0*sqrt(dble(n))
138: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
139: if (rank .eq. 0) write(6,150) v
140: 150 format ("VecAXPY ",1pe8.2)
142: call VecAYPX(y,two,x,ierr)
143: call VecNorm(y,NORM_2,norm,ierr)
144: v = norm-18.0*sqrt(dble(n))
145: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
146: if (rank .eq. 0) write(6,160) v
147: 160 format ("VecAYXP ",1pe8.2)
149: call VecSwap(x,y,ierr)
150: call VecNorm(y,NORM_2,norm,ierr)
151: v = norm-2.0*sqrt(dble(n))
152: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
153: if (rank .eq. 0) write(6,170) v
154: 170 format ("VecSwap ",1pe8.2)
156: call VecNorm(x,NORM_2,norm,ierr)
157: v = norm-18.0*sqrt(dble(n))
158: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
159: if (rank .eq. 0) write(6,180) v
160: 180 format ("VecSwap ",1pe8.2)
162: call VecWAXPY(w,two,x,y,ierr)
163: call VecNorm(w,NORM_2,norm,ierr)
164: v = norm-38.0*sqrt(dble(n))
165: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
166: if (rank .eq. 0) write(6,190) v
167: 190 format ("VecWAXPY ",1pe8.2)
169: call VecPointwiseMult(w,y,x,ierr)
170: call VecNorm(w,NORM_2,norm,ierr)
171: v = norm-36.0*sqrt(dble(n))
172: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
173: if (rank .eq. 0) write(6,200) v
174: 200 format ("VecPointwiseMult ",1pe8.2)
176: call VecPointwiseDivide(w,x,y,ierr)
177: call VecNorm(w,NORM_2,norm,ierr)
178: v = norm-9.0*sqrt(dble(n))
179: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
180: if (rank .eq. 0) write(6,210) v
181: 210 format ("VecPointwiseDivide ",1pe8.2)
183:
184: dots(1) = one
185: dots(2) = three
186: dots(3) = two
187: call VecSet(x,one,ierr)
188: call VecMAXPY(x,3,dots,z,ierr)
189: call VecNorm(z(1),NORM_2,norm,ierr)
190: v = norm-sqrt(dble(n))
191: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
192: call VecNorm(z(2),NORM_2,norm,ierr)
193: v1 = norm-2.0*sqrt(dble(n))
194: if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
195: call VecNorm(z(3),NORM_2,norm,ierr)
196: v2 = norm-3.0*sqrt(dble(n))
197: if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
198: if (rank .eq. 0) write(6,220) v,v1,v2
199: 220 format ("VecMAXPY ",3(1pe8.2))
202: ! Test whether vector has been corrupted (just to demonstrate this
203: ! routine) not needed in most application codes.
205: call VecValid(x,flg,ierr)
206: if (flg .ne. PETSC_TRUE) then
207: if (rank .eq. 0) then
208: write(6,*) 'Corrupted vector!'
209: endif
210: SETERRQ(1,' ',ierr)
211: endif
213: ! Free work space. All PETSc objects should be destroyed when they
214: ! are no longer needed.
216: call VecDestroy(x,ierr)
217: call VecDestroy(y,ierr)
218: call VecDestroy(w,ierr)
219: call VecDestroyVecsF90(z,3,ierr)
220: call PetscFinalize(ierr)
222: end
223: