Royal Belgian Institute for Aeronomy¶

uf428 - interpolating an altitude¶

subroutine uf428(falt, bi, ai, ifail)¶

Parameters:

falt [real8,in] :: Altitude to be interpolated.
bi [real8,out] :: Magnetic field intensity at the interpolated location.
ai [real8,out] :: Altitude at the interpolated location.
ifail [integer4,out] :: error flag (see Diagnostics)

Description¶

The subroutine uf428() interpolates an altitude (falt) along a field line. To be used, the common block uc170 has to include at least two points and the last Runge-Kutta step had to overreach the altitude falt. The subroutine uf428() combines linear interpolations and Runge-Kutta steps to determine the correct location of the altitude falt.

When the subroutine succeeds, the arguments bi and ai are set to the magnetic field intensity and altitude at the interpolated location, respectively. The index of the common block uc170 corresponding to the interpolated location is stored in the argument ifail.

Note

The subroutine takes into account the step size limit stplst defined in the common block uc190.

Diagnostics¶

-42801, altitude is constant

-42802, too many iterations

-42803, -42804, problem with the Runge Kutta step

-42805, boundary condition on the altitude is not between the altitudes of the last points

> 0, the index in uc170 corresponding to the interpolated location

Common Blocks¶

uc160 - general constants

uc170 - temporary magnetic field line

uc190 - control parameters, set 1

Dependencies¶

Called by¶

uf422 - follow a field line until a boundary condition is reached

Calls¶

uf423 - Runge Kutta step

Reported Bugs¶

None

Examples¶