Actual source code: ex1f90.F
petsc-3.4.5 2014-06-29
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: ! petscsys.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 <finclude/petscsys.h>
30: #include <finclude/petscvec.h>
31: #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: PetscInt n,ithree
45: PetscErrorCode ierr
46: PetscMPIInt rank
47: PetscBool flg
48: PetscScalar one,two,three
49: PetscScalar dots(3),dot
51: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
52: ! Beginning of program
53: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
55: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
56: one = 1.0
57: two = 2.0
58: three = 3.0
59: n = 20
60: ithree = 3
62: call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',n,flg,ierr)
63: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
65: ! Create a vector, specifying only its global dimension.
66: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
67: ! the vector format (currently parallel
68: ! or sequential) is determined at runtime. Also, the parallel
69: ! partitioning of the vector is determined by PETSc at runtime.
70: !
71: ! Routines for creating particular vector types directly are:
72: ! VecCreateSeq() - uniprocessor vector
73: ! VecCreateMPI() - distributed vector, where the user can
74: ! determine the parallel partitioning
76: call VecCreate(PETSC_COMM_WORLD,x,ierr)
77: call VecSetSizes(x,PETSC_DECIDE,n,ierr)
78: call VecSetFromOptions(x,ierr)
80: ! Duplicate some work vectors (of the same format and
81: ! partitioning as the initial vector).
83: call VecDuplicate(x,y,ierr)
84: call VecDuplicate(x,w,ierr)
86: ! Duplicate more work vectors (of the same format and
87: ! partitioning as the initial vector). Here we duplicate
88: ! an array of vectors, which is often more convenient than
89: ! duplicating individual ones.
91: call VecDuplicateVecsF90(x,ithree,z,ierr)
93: ! Set the vectors to entries to a constant value.
95: call VecSet(x,one,ierr)
96: call VecSet(y,two,ierr)
97: call VecSet(z(1),one,ierr)
98: call VecSet(z(2),two,ierr)
99: call VecSet(z(3),three,ierr)
101: ! Demonstrate various basic vector routines.
103: call VecDot(x,x,dot,ierr)
104: call VecMDot(x,ithree,z,dots,ierr)
106: ! Note: If using a complex numbers version of PETSc, then
107: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
108: ! (when using real numbers) it is undefined.
110: if (rank .eq. 0) then
111: #if defined(PETSC_USE_COMPLEX)
112: write(6,100) int(PetscRealPart(dot))
113: write(6,110) int(PetscRealPart(dots(1))), &
114: & int(PetscRealPart(dots(2))), &
115: & int(PetscRealPart(dots(3)))
116: #else
117: write(6,100) int(dot)
118: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
119: #endif
120: write(6,120)
121: endif
122: 100 format ("Vector length ",i6)
123: 110 format ("Vector length ",3(i6))
124: 120 format ("All other values should be near zero")
126: call VecScale(x,two,ierr)
127: call VecNorm(x,NORM_2,norm,ierr)
128: v = norm-2.0*sqrt(dble(n))
129: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
130: if (rank .eq. 0) write(6,130) v
131: 130 format ("VecScale ",1pe8.2)
133: call VecCopy(x,w,ierr)
134: call VecNorm(w,NORM_2,norm,ierr)
135: v = norm-2.0*sqrt(dble(n))
136: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
137: if (rank .eq. 0) write(6,140) v
138: 140 format ("VecCopy ",1pe8.2)
140: call VecAXPY(y,three,x,ierr)
141: call VecNorm(y,NORM_2,norm,ierr)
142: v = norm-8.0*sqrt(dble(n))
143: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
144: if (rank .eq. 0) write(6,150) v
145: 150 format ("VecAXPY ",1pe8.2)
147: call VecAYPX(y,two,x,ierr)
148: call VecNorm(y,NORM_2,norm,ierr)
149: v = norm-18.0*sqrt(dble(n))
150: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
151: if (rank .eq. 0) write(6,160) v
152: 160 format ("VecAYXP ",1pe8.2)
154: call VecSwap(x,y,ierr)
155: call VecNorm(y,NORM_2,norm,ierr)
156: v = norm-2.0*sqrt(dble(n))
157: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
158: if (rank .eq. 0) write(6,170) v
159: 170 format ("VecSwap ",1pe8.2)
161: call VecNorm(x,NORM_2,norm,ierr)
162: v = norm-18.0*sqrt(dble(n))
163: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
164: if (rank .eq. 0) write(6,180) v
165: 180 format ("VecSwap ",1pe8.2)
167: call VecWAXPY(w,two,x,y,ierr)
168: call VecNorm(w,NORM_2,norm,ierr)
169: v = norm-38.0*sqrt(dble(n))
170: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
171: if (rank .eq. 0) write(6,190) v
172: 190 format ("VecWAXPY ",1pe8.2)
174: call VecPointwiseMult(w,y,x,ierr)
175: call VecNorm(w,NORM_2,norm,ierr)
176: v = norm-36.0*sqrt(dble(n))
177: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
178: if (rank .eq. 0) write(6,200) v
179: 200 format ("VecPointwiseMult ",1pe8.2)
181: call VecPointwiseDivide(w,x,y,ierr)
182: call VecNorm(w,NORM_2,norm,ierr)
183: v = norm-9.0*sqrt(dble(n))
184: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
185: if (rank .eq. 0) write(6,210) v
186: 210 format ("VecPointwiseDivide ",1pe8.2)
189: dots(1) = one
190: dots(2) = three
191: dots(3) = two
192: call VecSet(x,one,ierr)
193: call VecMAXPY(x,ithree,dots,z,ierr)
194: call VecNorm(z(1),NORM_2,norm,ierr)
195: v = norm-sqrt(dble(n))
196: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
197: call VecNorm(z(2),NORM_2,norm,ierr)
198: v1 = norm-2.0*sqrt(dble(n))
199: if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
200: call VecNorm(z(3),NORM_2,norm,ierr)
201: v2 = norm-3.0*sqrt(dble(n))
202: if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
203: if (rank .eq. 0) write(6,220) v,v1,v2
204: 220 format ("VecMAXPY ",3(1pe8.2))
206: ! Free work space. All PETSc objects should be destroyed when they
207: ! are no longer needed.
209: call VecDestroy(x,ierr)
210: call VecDestroy(y,ierr)
211: call VecDestroy(w,ierr)
212: call VecDestroyVecsF90(ithree,z,ierr)
213: call PetscFinalize(ierr)
215: end