1 | program main |
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2 | |
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3 | !*****************************************************************************80 |
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4 | ! |
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5 | !! MAIN is the main program for QUADPACK_PRB. |
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6 | ! |
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7 | ! Discussion: |
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8 | ! |
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9 | ! QUADPACK_PRB tests the QUADPACK library. |
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10 | ! |
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11 | ! Modified: |
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12 | ! |
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13 | ! 03 February 2007 |
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14 | ! |
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15 | ! Author: |
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16 | ! |
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17 | ! John Burkardt |
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18 | ! |
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19 | implicit none |
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20 | |
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21 | |
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22 | write ( *, '(a)' ) ' ' |
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23 | write ( *, '(a)' ) 'QUADPACK_PRB' |
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24 | write ( *, '(a)' ) ' FORTRAN90 version' |
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25 | write ( *, '(a)' ) ' Test the QUADPACK library.' |
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26 | |
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27 | call test01 ( ) |
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28 | |
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29 | ! |
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30 | ! Terminate. |
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31 | ! |
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32 | write ( *, '(a)' ) ' ' |
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33 | write ( *, '(a)' ) 'QUADPACK_PRB' |
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34 | write ( *, '(a)' ) ' Normal end of execution.' |
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35 | write ( *, '(a)' ) ' ' |
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36 | |
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37 | stop |
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38 | end |
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39 | |
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40 | |
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41 | subroutine test01 ( ) |
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42 | |
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43 | !*****************************************************************************80 |
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44 | ! |
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45 | !! TEST01 tests QAG. |
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46 | ! |
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47 | ! Discussion: |
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48 | ! |
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49 | ! QAG is an adaptive automatic integrator using a Gauss-Kronrod rule. |
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50 | ! |
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51 | ! integrate cos(100*sin(x)) from 0 to pi. |
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52 | ! |
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53 | ! The exact answer is pi * j0(100), or roughly 0.06278740. |
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54 | ! |
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55 | ! KEY chooses the order of the integration rule, from 1 to 6. |
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56 | ! |
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57 | implicit none |
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58 | |
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59 | real, parameter :: a = 0.0E+00 |
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60 | real abserr |
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61 | real b |
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62 | real, parameter :: epsabs = 0.0E+00 |
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63 | real, parameter :: epsrel = 0.001E+00 |
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64 | real, external :: f02 |
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65 | integer ier |
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66 | integer, parameter :: key = 6 |
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67 | integer neval |
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68 | real, parameter :: pi = 3.141592653589793E+00 |
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69 | real result |
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70 | real, parameter :: true = 0.06278740E+00 |
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71 | real, parameter :: limit = 200 |
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72 | |
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73 | |
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74 | b = pi |
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75 | |
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76 | |
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77 | |
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78 | |
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79 | call qag ( f02, a, b, epsabs, epsrel, key, result, abserr, neval, ier) |
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80 | |
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81 | write ( *, '(a)' ) ' ' |
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82 | write ( *, '(a)' ) 'TEST01' |
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83 | write ( *, '(a)' ) ' Test QAG' |
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84 | write ( *, '(a)' ) ' ' |
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85 | write ( *, '(a)' ) ' Integrand is COS(100*SIN(X))' |
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86 | write ( *, '(a,g14.6)' ) ' Integral left endpoint A = ', a |
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87 | write ( *, '(a,g14.6)' ) ' Integral right endpoint B = ', b |
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88 | write ( *, '(a,g14.6)' ) ' Exact integral is ', true |
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89 | write ( *, '(a,g14.6)' ) ' Estimated integral is ', result |
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90 | write ( *, '(a,g14.6)' ) ' Estimated integral error = ', abserr |
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91 | write ( *, '(a,g14.6)' ) ' Exact integral error = ', true - result |
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92 | write ( *, '(a,i8)' ) ' Number of function evaluations, NEVAL = ', neval |
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93 | write ( *, '(a,i8)' ) ' Error return code IER = ', ier |
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94 | |
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95 | return |
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96 | end |
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97 | |
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98 | |
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99 | |
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100 | function f02 ( x ) |
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101 | |
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102 | !*****************************************************************************80 |
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103 | ! F02 is the integrand function COS(100*SIN(X)). |
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104 | !*****************************************************************************80 |
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105 | |
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106 | implicit none |
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107 | real f02 |
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108 | real x |
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109 | |
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110 | f02 = cos ( 100.0E+00 * sin ( x ) ) |
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111 | |
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112 | return |
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113 | end function f02 |
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114 | |
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