Actual source code: ex1f90.F
petsc-3.7.5 2017-01-01
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 <petsc/finclude/petscsys.h>
30: #include <petsc/finclude/petscvec.h>
31: #include <petsc/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: PetscReal 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
50: PetscReal nfloat
52: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
53: ! Beginning of program
54: ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
56: call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
57: one = 1.0
58: two = 2.0
59: three = 3.0
60: n = 20
61: ithree = 3
63: call PetscOptionsGetInt(PETSC_NULL_OBJECT,PETSC_NULL_CHARACTER, &
64: & '-n',n,flg,ierr)
65: nfloat = n
66: call MPI_Comm_rank(PETSC_COMM_WORLD,rank,ierr)
68: ! Create a vector, specifying only its global dimension.
69: ! When using VecCreate(), VecSetSizes() and VecSetFromOptions(),
70: ! the vector format (currently parallel
71: ! or sequential) is determined at runtime. Also, the parallel
72: ! partitioning of the vector is determined by PETSc at runtime.
73: !
74: ! Routines for creating particular vector types directly are:
75: ! VecCreateSeq() - uniprocessor vector
76: ! VecCreateMPI() - distributed vector, where the user can
77: ! determine the parallel partitioning
79: call VecCreate(PETSC_COMM_WORLD,x,ierr)
80: call VecSetSizes(x,PETSC_DECIDE,n,ierr)
81: call VecSetFromOptions(x,ierr)
83: ! Duplicate some work vectors (of the same format and
84: ! partitioning as the initial vector).
86: call VecDuplicate(x,y,ierr)
87: call VecDuplicate(x,w,ierr)
89: ! Duplicate more work vectors (of the same format and
90: ! partitioning as the initial vector). Here we duplicate
91: ! an array of vectors, which is often more convenient than
92: ! duplicating individual ones.
94: call VecDuplicateVecsF90(x,ithree,z,ierr)
96: ! Set the vectors to entries to a constant value.
98: call VecSet(x,one,ierr)
99: call VecSet(y,two,ierr)
100: call VecSet(z(1),one,ierr)
101: call VecSet(z(2),two,ierr)
102: call VecSet(z(3),three,ierr)
104: ! Demonstrate various basic vector routines.
106: call VecDot(x,x,dot,ierr)
107: call VecMDot(x,ithree,z,dots,ierr)
109: ! Note: If using a complex numbers version of PETSc, then
110: ! PETSC_USE_COMPLEX is defined in the makefiles; otherwise,
111: ! (when using real numbers) it is undefined.
113: if (rank .eq. 0) then
114: #if defined(PETSC_USE_COMPLEX)
115: write(6,100) int(PetscRealPart(dot))
116: write(6,110) int(PetscRealPart(dots(1))), &
117: & int(PetscRealPart(dots(2))), &
118: & int(PetscRealPart(dots(3)))
119: #else
120: write(6,100) int(dot)
121: write(6,110) int(dots(1)),int(dots(2)),int(dots(3))
122: #endif
123: write(6,120)
124: endif
125: 100 format ('Vector length ',i6)
126: 110 format ('Vector length ',3(i6))
127: 120 format ('All other values should be near zero')
129: call VecScale(x,two,ierr)
130: call VecNorm(x,NORM_2,norm,ierr)
131: v = abs(norm-2.0*sqrt(nfloat))
132: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
133: if (rank .eq. 0) write(6,130) v
134: 130 format ('VecScale ',1pe8.2)
136: call VecCopy(x,w,ierr)
137: call VecNorm(w,NORM_2,norm,ierr)
138: v = abs(norm-2.0*sqrt(nfloat))
139: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
140: if (rank .eq. 0) write(6,140) v
141: 140 format ('VecCopy ',1pe8.2)
143: call VecAXPY(y,three,x,ierr)
144: call VecNorm(y,NORM_2,norm,ierr)
145: v = abs(norm-8.0*sqrt(nfloat))
146: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
147: if (rank .eq. 0) write(6,150) v
148: 150 format ('VecAXPY ',1pe8.2)
150: call VecAYPX(y,two,x,ierr)
151: call VecNorm(y,NORM_2,norm,ierr)
152: v = abs(norm-18.0*sqrt(nfloat))
153: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
154: if (rank .eq. 0) write(6,160) v
155: 160 format ('VecAYXP ',1pe8.2)
157: call VecSwap(x,y,ierr)
158: call VecNorm(y,NORM_2,norm,ierr)
159: v = abs(norm-2.0*sqrt(nfloat))
160: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
161: if (rank .eq. 0) write(6,170) v
162: 170 format ('VecSwap ',1pe8.2)
164: call VecNorm(x,NORM_2,norm,ierr)
165: v = abs(norm-18.0*sqrt(nfloat))
166: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
167: if (rank .eq. 0) write(6,180) v
168: 180 format ('VecSwap ',1pe8.2)
170: call VecWAXPY(w,two,x,y,ierr)
171: call VecNorm(w,NORM_2,norm,ierr)
172: v = abs(norm-38.0*sqrt(nfloat))
173: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
174: if (rank .eq. 0) write(6,190) v
175: 190 format ('VecWAXPY ',1pe8.2)
177: call VecPointwiseMult(w,y,x,ierr)
178: call VecNorm(w,NORM_2,norm,ierr)
179: v = abs(norm-36.0*sqrt(nfloat))
180: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
181: if (rank .eq. 0) write(6,200) v
182: 200 format ('VecPointwiseMult ',1pe8.2)
184: call VecPointwiseDivide(w,x,y,ierr)
185: call VecNorm(w,NORM_2,norm,ierr)
186: v = abs(norm-9.0*sqrt(nfloat))
187: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
188: if (rank .eq. 0) write(6,210) v
189: 210 format ('VecPointwiseDivide ',1pe8.2)
192: dots(1) = one
193: dots(2) = three
194: dots(3) = two
195: call VecSet(x,one,ierr)
196: call VecMAXPY(x,ithree,dots,z,ierr)
197: call VecNorm(z(1),NORM_2,norm,ierr)
198: v = abs(norm-sqrt(nfloat))
199: if (v .gt. -1.d-10 .and. v .lt. 1.d-10) v = 0.0
200: call VecNorm(z(2),NORM_2,norm,ierr)
201: v1 = abs(norm-2.0*sqrt(nfloat))
202: if (v1 .gt. -1.d-10 .and. v1 .lt. 1.d-10) v1 = 0.0
203: call VecNorm(z(3),NORM_2,norm,ierr)
204: v2 = abs(norm-3.0*sqrt(nfloat))
205: if (v2 .gt. -1.d-10 .and. v2 .lt. 1.d-10) v2 = 0.0
206: if (rank .eq. 0) write(6,220) v,v1,v2
207: 220 format ('VecMAXPY ',3(1pe8.2))
209: ! Free work space. All PETSc objects should be destroyed when they
210: ! are no longer needed.
212: call VecDestroy(x,ierr)
213: call VecDestroy(y,ierr)
214: call VecDestroy(w,ierr)
215: call VecDestroyVecsF90(ithree,z,ierr)
216: call PetscFinalize(ierr)
218: end