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!! spline parameters. |
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!! |
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!! @author Charles F. Vardeman II |
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!! @version $Id: interpolation.F90,v 1.5 2006-04-14 21:59:23 gezelter Exp $ |
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!! @version $Id: interpolation.F90,v 1.6 2006-04-17 21:49:12 gezelter Exp $ |
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< |
module INTERPOLATION |
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> |
module interpolation |
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use definitions |
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use status |
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implicit none |
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character(len = statusMsgSize) :: errMSG |
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type, public :: cubicSpline |
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private |
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logical :: isUniform = .false. |
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integer :: np = 0 |
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real(kind=dp) :: dx_i |
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public :: newSpline |
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public :: deleteSpline |
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public :: lookup_spline |
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public :: lookup_uniform_spline |
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public :: lookup_nonuniform_spline |
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public :: lookupSpline |
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> |
public :: lookupUniformSpline |
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> |
public :: lookupNonuniformSpline |
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> |
public :: lookupUniformSpline1d |
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contains |
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end subroutine deleteSpline |
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subroutine lookup_nonuniform_spline(cs, xval, yval) |
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> |
subroutine lookupNonuniformSpline(cs, xval, yval) |
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!************************************************************************* |
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! |
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! lookup_nonuniform_spline evaluates a piecewise cubic Hermite interpolant. |
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! lookupNonuniformSpline evaluates a piecewise cubic Hermite interpolant. |
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! |
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! Discussion: |
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! |
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yval = cs%c(1,j) + dx * ( cs%c(2,j) + dx * ( cs%c(3,j) + dx * cs%c(4,j) ) ) |
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return |
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< |
end subroutine lookup_nonuniform_spline |
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> |
end subroutine lookupNonuniformSpline |
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|
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< |
subroutine lookup_uniform_spline(cs, xval, yval) |
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> |
subroutine lookupUniformSpline(cs, xval, yval) |
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!************************************************************************* |
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! |
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< |
! lookup_uniform_spline evaluates a piecewise cubic Hermite interpolant. |
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> |
! lookupUniformSpline evaluates a piecewise cubic Hermite interpolant. |
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! |
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! Discussion: |
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! |
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type (cubicSpline), intent(in) :: cs |
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real( kind = DP ), intent(in) :: xval |
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real( kind = DP ), intent(out) :: yval |
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< |
real( kind = DP ) :: dx |
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> |
real( kind = DP ) :: a, b, c, d, dx |
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integer :: i, j |
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! |
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! Find the interval J = [ cs%x(J), cs%x(J+1) ] that contains |
| 332 |
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dx = xval - cs%x(j) |
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< |
yval = cs%c(1,j) + dx * ( cs%c(2,j) + dx * ( cs%c(3,j) + dx * cs%c(4,j) ) ) |
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> |
a = cs%c(1,j) |
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> |
b = cs%c(2,j) |
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> |
c = cs%c(3,j) |
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> |
d = cs%c(4,j) |
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> |
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| 340 |
> |
yval = c + dx * d |
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> |
yval = b + dx * yval |
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> |
yval = a + dx * yval |
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return |
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< |
end subroutine lookup_uniform_spline |
| 345 |
> |
end subroutine lookupUniformSpline |
| 346 |
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< |
subroutine lookup_spline(cs, xval, yval) |
| 347 |
> |
subroutine lookupUniformSpline1d(cs, xval, yval, dydx) |
| 348 |
> |
|
| 349 |
> |
implicit none |
| 350 |
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| 351 |
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type (cubicSpline), intent(in) :: cs |
| 352 |
+ |
real( kind = DP ), intent(in) :: xval |
| 353 |
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real( kind = DP ), intent(out) :: yval, dydx |
| 354 |
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real( kind = DP ) :: a, b, c, d, dx |
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integer :: i, j |
| 356 |
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|
| 357 |
+ |
! Find the interval J = [ cs%x(J), cs%x(J+1) ] that contains |
| 358 |
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! or is nearest to xval. |
| 359 |
+ |
|
| 360 |
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j = MAX(1, MIN(cs%np, idint((xval-cs%x(1)) * cs%dx_i) + 1)) |
| 361 |
+ |
|
| 362 |
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dx = xval - cs%x(j) |
| 363 |
+ |
|
| 364 |
+ |
a = cs%c(1,j) |
| 365 |
+ |
b = cs%c(2,j) |
| 366 |
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c = cs%c(3,j) |
| 367 |
+ |
d = cs%c(4,j) |
| 368 |
+ |
|
| 369 |
+ |
yval = c + dx * d |
| 370 |
+ |
yval = b + dx * yval |
| 371 |
+ |
yval = a + dx * yval |
| 372 |
+ |
|
| 373 |
+ |
dydx = 2.0d0 * c + 3.0d0 * d * dx |
| 374 |
+ |
dydx = b + dx * dydx |
| 375 |
+ |
|
| 376 |
+ |
return |
| 377 |
+ |
end subroutine lookupUniformSpline1d |
| 378 |
+ |
|
| 379 |
+ |
subroutine lookupSpline(cs, xval, yval) |
| 380 |
+ |
|
| 381 |
+ |
type (cubicSpline), intent(in) :: cs |
| 382 |
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real( kind = DP ), intent(inout) :: xval |
| 383 |
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real( kind = DP ), intent(inout) :: yval |
| 384 |
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|
| 385 |
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if (cs%isUniform) then |
| 386 |
< |
call lookup_uniform_spline(cs, xval, yval) |
| 386 |
> |
call lookupUniformSpline(cs, xval, yval) |
| 387 |
|
else |
| 388 |
< |
call lookup_nonuniform_spline(cs, xval, yval) |
| 388 |
> |
call lookupNonuniformSpline(cs, xval, yval) |
| 389 |
|
endif |
| 390 |
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|
| 391 |
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return |
| 392 |
< |
end subroutine lookup_spline |
| 392 |
> |
end subroutine lookupSpline |
| 393 |
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|
| 394 |
< |
end module INTERPOLATION |
| 394 |
> |
end module interpolation |
